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In this study, we investigated the effect of high temperature on the mechanical behavior of Hwangdeung granite in Korea. Uniaxial compression and Brazilian tests were performed under temperatures ranging from 20 °C to 250 °C. The development of the thermally induced microcracks was observed utilizing a scanning electron microscope (SEM). The target temperature was chosen for rock engineering projects, such as high-level radioactive waste disposal, enhanced geothermal energy, and thermal energy storage. Considering the long-term strength and fracture process associated with crack development, we examined the temperature dependence of crack initiation and propagation thresholds and conventional strength and deformation parameters, as well as the stress-strain relation under high temperature. Compressive strength, tensile strength, and Young's modulus decreased with increasing temperature, particularly at temperatures above 100 °C, and Poisson's ratio decreased linearly. The changes in the tensile strength and elastic constants were more pronounced than those in uniaxial compressive strength. The stress-strain curves revealed that the thermal effect on deformation, rather than strength, was evident. Microscopic observations of the heated rock samples have revealed that high temperature promoted the interaction and networking of pre-existing and thermally induced cracks, resulting in microstructural damage before loading. We determined the crack closure stress, crack initiation stress, and crack damage stress under the respective temperatures by analyzing the stress-strain curves. An increase in temperature increased the crack closure stress and reduced the crack initiation stress, resulting in a decreased elastic range; the former increased by 12.1 MPa as the temperature increased from 20 °C to 250 °C, and the latter significantly reduced by 25.1 MPa. This finding suggests that the mechanical behavior of rocks or rock masses under high-temperature conditions, particularly at low-stress levels, is uncertain and cannot be approximated with standard material properties. No systemic relation was detected between temperature and crack damage stress; however, the volumetric strain at the crack damage stress increased consistently with temperature. [ABSTRACT FROM AUTHOR]

This article proposes a new control method for the synchronous rectifier (SR) of phase-shifted full-bridge (PSFB) converter to improve its efficiency in light-load condition. In general, the PSFB converter operates in the discontinuous conduction mode (DCM) in light-load condition to reduce the effective duty-ratio and core loss. However, the conventional control methods in the DCM cause undesirable conduction loss in SR because the output inductor current flows through the body-diode instead of the channel of SR. To figure it out, the proposed control method modulates the turn-on time of SR to eliminate the body-diode conduction. Moreover, it can be easily implemented without any auxiliary circuits. Therefore, it can improve the efficiency in light-load condition while keeping the advantages of DCM. The operating principle of PSFB converter in the DCM is first described. Thereafter, the proposed control method for SR is theoretically analyzed. Finally, its practical effectiveness is verified by experimental tests on the hardware implementation. [ABSTRACT FROM AUTHOR]

This article proposes a novel sawtooth-carrier based pulsewidth-modulation (SCPWM) method for quasi-Z-source inverter (qZSI) with the zero-voltage-switching (ZVS) operation to reduce the total harmonic distortion (THD) and inductor current ripple. The conventional variable-duty pulsewidth-modulation (VDPWM) method has been being used for qZSIs because it causes the low switching loss. However, this method has the limitation not only to improve the THD of output current but also to reduce the size of inductor when it is applied to the qZSI. To figure it out, the proposed SCPWM method uses the sawtooth-carrier signal while keeping the benefit from the use of variable duty. In particular, the ZVS operation occurs whenever the edge of sawtooth-carrier signal is located in the time interval of shoot-through state. This allows to increase the carrier frequency of qZSI without any additional switching loss. Thus, both the THD of output current and the inductor current ripple can be reduced while keeping the high efficiency of system. The operating principle of the proposed SCPWM method is first explained in detail. Thereafter, its performance is mathematically analyzed and compared with that of conventional VDPWM method. Finally, its practical effectiveness is verified by the hardware experimental test. [ABSTRACT FROM AUTHOR]

The output voltage of renewable energy sources is influenced by environmental conditions. To compensate for the variations of voltage, a buck–boost power conditioning system can be used. This article presents a full-bridge single-inductor-based buck–boost inverter. Its output voltage can be greater or lower than the input voltage depending on the controllable duty ratio. This inverter features bidirectional and reactive power flow operations with no high-frequency common-mode voltage. The unique feature of the proposed inverter is using a single inductor in the power train, which enhances the power density. Moreover, only two switches can operate at high frequency. This enables the inverter to be made with the high efficiency and simple circuit configuration. Based on the proposed full-bridge inverter, a novel cascaded buck–boost inverter is also presented. It retains all the benefits of the proposed full-bridge inverter. The theoretical analysis of the proposed full-bridge inverter is first explained in detail. It is then extended to a cascaded inverter. Thereafter, the practical effectiveness of the proposed inverters is verified with the experimental tests by implementing the hardware prototypes of 110 Vrms, 60 Hz, and 500 W for full-bridge single-inductor-based buck–boost inverter, and 220 Vrms, 60 Hz, and 1000 W for the cascaded inverter. [ABSTRACT FROM AUTHOR]

The use of potent therapies inhibiting critical oncogenic pathways active in epithelial cancers has led to multiple resistance mechanisms, including the development of highly aggressive, small cell neuroendocrine carcinoma (SCNC). SCNC patients have a dismal prognosis due in part to a limited understanding of the molecular mechanisms driving this malignancy and the lack of effective treatments. Here, we demonstrate that a common set of defined oncogenic drivers reproducibly reprograms normal human prostate and lung epithelial cells to small cell prostate cancer (SCPC) and small cell lung cancer (SCLC), respectively. We identify shared active transcription factor binding regions in the reprogrammed prostate and lung SCNCs by integrative analyses of epigenetic and transcriptional landscapes. These results suggest that neuroendocrine cancers arising from distinct epithelial tissues may share common vulnerabilities that could be exploited for the development of drugs targeting SCNCs. [ABSTRACT FROM AUTHOR]

Recently, microgrids have faced a great challenge for the stable operation of converter-dominant system with very high renewable penetration. The converter-based-generator reduces inertia constant. In this case, very small power imbalance can cause large frequency variation. Therefore, the accurate load sharing between generators is important for the stable operation. This paper proposes the virtual multi-slack (VMS) droop control based on the power sensitivity analysis. In other words, one physical slack generator directly controls the magnitude and phase angle of its bus voltage. At the same time, the other generators indirectly control the magnitudes and phase angles of their bus voltages by using the VMS droop control. This results in the proper load sharing between the generators in the stand-alone microgrid. That is, all nonslack generators operate as virtual slacks so that they solve the power imbalances together with one physical slack generator. The proposed VMS control is realized with the multi-slack power flow analysis, which enables adaptive droop based power allocation between the generators. Then, its effectiveness is verified with several case studies on the practical stand-alone microgrid in South Korea by using the electromagnetic transient program. [ABSTRACT FROM PUBLISHER]

This paper describes the development of a new buck cascaded buck–boost power factor correction (PFC) converter of 2 kW with a soft-switching technique. For its wide range of input voltage, it operates in both buck and boost modes. The parameters are properly selected to endure voltage and current stress in all operating ranges. In addition, the electromagnetic interference (EMI) filter is used to reduce the EMI noise and guarantee continuous input current in buck operation. Moreover, the zero-voltage-transient pulse-width-modulation (ZVT-PWM) method is applied to improve the overall efficiency of the converter. The performance of the proposed PFC converter with the widest range of input voltage is evaluated by the hardware experimental test including harmonics analysis based on the International Electrotechnical Commission standard in all operating ranges. Also, the variations of power factor are theoretically analyzed in both buck and boost modes to determine the widest input range of the proposed PFC converter of 2 kW with an EMI filter. These are strongly required to commercialize it in practice. Finally, the efficiency of proposed PFC converter is compared with that of a conventional buck cascaded buck–boost PFC converter under various conditions. [ABSTRACT FROM PUBLISHER]

We numerically model the thermal-hydrological-mechanical (THM) processes within the rock mass surrounding a cavern used for thermal energy storage (TES). We consider a cylindrical rock cavern with a height of 50 m and a radius of 10 m storing thermal energy of 350 °C as a conceptual TES model, and simulate its operation for thirty years. At first, the insulator performance are not considered for the purpose of investigating the possible coupled THM behavior of the surrounding rock mass; then, the effects of an insulator are examined for different insulator thicknesses. The key concerns are hydro-thermal multiphase flow and heat transport in the rock mass around the thermal storage cavern, the effect of evaporation of rock mass, thermal impact on near the ground surface and the mechanical behavior of the surrounding rock mass. It is shown that the rock temperature around the cavern rapidly increases in the early stage and, consequently, evaporation of groundwater occurs, raising the fluid pressure. However, evaporation and multiphase flow does not have a significant effect on the heat transfer and mechanical behavior in spite of the high-temperature (350 °C) heat source. The simulations showed that large-scale heat flow around a cavern is expected to be conduction-dominated for a reasonable value of rock mass permeability. Thermal expansion as a result of the heating of the rock mass from the storage cavern leads to a ground surface uplift on the order of a few centimeters, and to the development of tensile stress above the storage cavern, increasing the potentials for shear and tensile failures after a few years of the operation. Finally, the analysis shows that high tangential stress in proximity of the storage cavern can some shear failure and local damage, although large rock wall failure could likely be controlled with appropriate insulators and reinforcement. [ABSTRACT FROM AUTHOR]

Background and purpose Patients with human papillomavirus related (HPV+) head and neck cancers (HNCs) demonstrate improved clinical outcomes compared to traditional HPV negative (HPV−) HNC patients. We have recently shown that HPV+ HNC cells are more sensitive to radiation than HPV− HNC cells. However, roles of HPV oncogenes in regulating the response of DNA damage repair remain unknown. Material and methods Using immortalized normal oral epithelial cell lines, HPV+ HNC derived cell lines, and HPV16 E7-transgenic mice we assessed the repair of DNA damage using γ-H2AX foci, single and split dose clonogenic survival assays, and immunoblot. The ability of E7 to modulate expression of proteins associated with DNA repair pathways was assessed by immunoblot. Results HPV16 E7 increased retention of γ-H2AX nuclear foci and significantly decreased sublethal DNA damage repair. While phospho-ATM, phospho-ATR, Ku70, and Ku80 expressions were not altered by E7, Rad51 was induced by E7. Correspondingly, HPV+ HNC cell lines showed retention of Rad51 after γ-radiation. Conclusions Our findings provide further understanding as to how HPV16 E7 manipulates cellular DNA damage responses that may underlie its oncogenic potential and influence the altered sensitivity to radiation seen in HPV+ HNC as compared to HPV− HNC. [ABSTRACT FROM AUTHOR]

HPV oncogenes and ERα are required for cervical carcinogenesis. Transcriptional regulation by ERα is mediated by ERE-dependent and ERE-independent mechanism. Our current study demonstrates that ERE-dependent mechanism of ERα is required for cervical carcinogenesis in HPV transgenic mouse model.Cervical cancer is caused by human papillomavirus (HPV) in collaboration with other non-viral factors. The uterine cervix is hormone responsive and female hormones have been implicated in the pathogenesis of the disease. HPV transgenic mice expressing HPV16 oncogenes E6 (K14E6) and/or E7 (K14E7) have been employed to study a mechanism of estrogen and estrogen receptor α (ERα) in cervical carcinogenesis. A chronic exposure to physiological levels of exogenous estrogen leads to cervical cancer in the HPV transgenic mice, which depends on ERα. The receptor is composed of multiple functional domains including a DNA-binding domain (DBD), which mediates its binding to estrogen-responsive elements (EREs) on target genes. A transcriptional control of genes by ERα is mediated by either DBD-dependent (classical) or DBD-independent (non-classical) pathway. Although molecular mechanisms of ERα in cancer have been characterized extensively, studies investigating importance of each pathway for carcinogenesis are scarce. In this study, we employ knock-in mice expressing an ERα DBD mutant (E207A/G208A) that is defective specifically for ERE binding. We demonstrate that the ERα DBD mutant fails to support estrogen-induced epithelial cell proliferation and carcinogenesis in the cervix of K14E7 transgenic mice. We also demonstrate that cervical diseases are absent in K14E7 mice when one ERα DBD mutant allele and one wild-type allele are present. We conclude that the ERα classical pathway is required for cervical carcinogenesis in a mouse model. [ABSTRACT FROM AUTHOR]

The islanding detection is one of the most important issues for grid-connection of the distributed generation (DG) systems. Several recent researches have developed two types of islanding detection methods (IDMs) with high-performance. One is the power and voltage (P-V) characteristic of load based IDM, and the other is the inverter's switching frequency based IDM. Although the above IDMs have no non-detection zone (NDZ) theoretically, their usefulness mainly depends on the control performance of the inverter in practice. In other words, the inverter must achieve the decoupled real and reactive control and successful operation of phase-locked loop (PLL). To deal with these problems, this paper describes the design of inverter controller to improve both system stability and islanding detection performance with the NDZ. The proposed controller uses the magnitude and phase of measured voltage directly instead of using the direct and quadrature axes voltages and currents. Additionally, it does not need an instant phase of point of common coupling (PCC) voltage, which is required in the conventional controller, and therefore makes it possible for the PLL independent control. Several case studies are carried out to verify that the proposed controller has better performance than the conventional controller. [ABSTRACT FROM PUBLISHER]

A new constitutive model to describe the shear behavior of rock joints under constant normal stiffness (CNS) and constant normal load (CNL) conditions is proposed. The model was developed using an empirical approach based on the results of a total of 362 direct shear tests on tensile fractured rock joints and replicas of tensile joints and on a new quantitative roughness parameter. This parameter, the active roughness coefficient C, is derived from the features of the effective roughness mobilized at the contact areas during shearing. The model involves a shear strength criterion and the relations between stresses and displacements in the normal and shear directions, where the effects of the boundary conditions and joint properties are considered by the shape indices C and C. The model can be used to predict the shear behavior under CNS as well as CNL conditions. The shear behavior obtained from the experimental results is generally in good agreement with that estimated by the proposed model, and the effects of joint roughness, initial normal stress, and normal stiffness are reasonably reflected in the model. [ABSTRACT FROM AUTHOR]

This paper describes a method for implementing a gradient-based nonlinear optimization technique for optimal tuning of nonlinear power system controllers such as a flexible ac transmission system (FACTS) via a combination of hardware and software in the real-time digital simulator (RTDS). The RTDS offers fundamental advantages over other commercial software tools because it is a fully digital power system simulator that operates in real time. Therefore, nonlinear optimal parameters can be effectively determined under similar environments to actual physical systems by this real-time implementation. In this paper, the Broyden–Fletcher–Goldfarb–Shanno optimization algorithm, which has a quadratic convergence property, is implemented in order to design the nonlinear controllers in power systems. Its effectiveness is demonstrated with two design examples intended to improve low-frequency oscillation damping in power systems. After illustrating an example to optimize the nonlinear parameters of the power system stabilizer, this paper introduces the optimal design of an external controller for the series capacitive reactance compensator, which is one of the FACTS devices, in real-time simulation. [ABSTRACT FROM AUTHOR]

The selection of placement and size for multiple distributed generators based on renewable energies becomes an important issue in operating modern power systems safely and reliably. This paper extends the previous study in our earlier paper by treating the problems for their optimal locations and sizes in more realistic way based on the power loss sensitivities and Kalman filter algorithm, respectively. In particular, the proposed method is implemented by the simulation on a part of practical distribution network of 60 MVA scale, which is located at the Do-gok area in Seoul, Korea. The new factor, called as the optimal locator index, is developed to determine the optimal locations in a systematic and effective manner by the power loss sensitivities. Also, the Kalman filter algorithm is applied to determine the optimal sizes by choosing the step size of 10 KW, which is a much smaller increment than the 10-MW step used in our earlier paper, without requiring high computational efforts. This selected step size of 10 KW is realistic and suitable to apply in practical test systems. [ABSTRACT FROM AUTHOR]

Abstract: A numerical method to determine the contact areas of a rock joint under normal and shear loads is proposed. The method requires only three-dimensional surface coordinates at the initial stage before shearing, while some disparate materials are inserted between the joint surfaces or particular equipments are adopted for measurement of the contact areas during the test in other conventional methods. The joint surface is modeled as a group of triangular planes, and the contact condition of each plane is examined by calculating the relative displacements of both surfaces from their initial locations. To verify the method, a direct shear test on a rock joint was simulated using a bonded particle model in a discrete element code. The locations of the contact areas observed in the simulation showed good agreement with those determined using the proposed method. To characterize the roughness of the joint surface including the contact area, the concept of ‘active and inactive micro-slope angle’ was defined based on the apparent inclination of the triangular element to the shear direction. To apply these techniques, the experimental results of shear tests on replicas of rock joints were analyzed for the location, size and micro-slope angle of contact areas according to the following shearing stages: pre-peak, peak, post-peak and residual. The locations of the contact areas were closely correlated with the distribution of the micro-slope angle, which indicates that the joint roughness should be qualified with respect to the shear direction and the corresponding contact area. Additionally, the proposed method was applied to estimation of the distribution of aperture size within a rock joint. [Copyright &y& Elsevier]

Abstract: This paper presents the design of a NAND flash based solid state disk (SSD), which can support various storage access patterns commonly observed in a PC environment. It is based on a hybrid model of high-performance SLC (single-level cell) NAND and low cost MLC (multi-level cell) NAND flash memories. Typically, SLC NAND has a higher transfer rate and greater cell endurance than MLC NAND flash memory. MLC NAND, on the other hand, benefits from lower price and higher capacity. In order to achieve higher performance than traditional SSDs, an interleaving technique that places NAND flash chips in parallel is essential. However, using the traditional FTL (flash translation layer) on an SSD with only MLC NAND chips is inefficient because the size of a logical block becomes large as the mapping address unit grows. In this paper, we proposed a HFTL (hybrid flash translation layer) which makes use of chained-blocks, combining SLC NAND and MLC NAND flash memories in parallel. Experimental results show that for most of the traces studied, the HFTL in an SSD configuration composed of 80% MLC NAND and 20% SLC NAND memories can improve performance compared to other solid state disk configurations, composed of either SLC NAND or MLC NAND flash memory alone. [Copyright &y& Elsevier]

Abstract: In order to guarantee both performance and programmability demands in 3D graphics applications, vector and multithreaded SIMD architectures have been employed in recent graphics processing units. This paper introduces a novel instruction-systolic array architecture, which transfers an instruction stream in a pipelined fashion to efficiently share the expensive functional resources of a graphics processor. Specifically, cache misses and dynamic branches can cause additional latencies and complicated management in these parallel architectures. To address this problem, we combine a systolic execution scheme with on-demand warp activation that handles cache miss latency and branch divergence efficiently without significantly increasing hardware resources, either in terms of logic or register space. Simulation indicates that the proposed architecture offers 25% better performance than a traditional SIMD architecture with the same resources, and requires significantly fewer resources to match the performance of a typical modern vector multi-threaded GPU architecture. [Copyright &y& Elsevier]

This paper describes the Hessian matrix estimation of nonsmooth nonlinear parameters by the identifier based on a feedforward neural network (FFNN) embedded in a hybrid system, which is modeled by the differential–algebraic–impulsive–switched (DAIS) structure. After identifying full dynamics of the hybrid system, the FFNN is used to estimate second-order derivatives of an objective function \bf J with respect to the nonlinear parameters from the gradient information, which are trajectory sensitivities. Then, the estimated Hessian matrix is applied to the optimal tuning of a saturation limiter used in a practical engineering system. [ABSTRACT FROM PUBLISHER]

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Some non-anti-arrhythmic drugs delay cardiac repolarization, which can be measured as an increase in the QT interval. Delays in cardiac repolarization create an electrophysiological environment that favours the development of cardiac arrhythmias, which may lead to torsade de pointes, which can be fatal. As part of the clinical development of eltrombopag, a thorough QTc study was conducted to evaluate the effects of eltrombopag on cardiac repolarization at both therapeutic and supratherapeutic doses and to characterize the relationship between plasma eltrombopag concentrations and change in QTc. WHAT THIS STUDY ADDS This study found no clinically significant QT prolongation for eltrombopag when administered as 50 mg or 150 mg every day for 5 days. There were no safety or tolerability signals of clinical concern. A small incidence of ventricular premature beats was observed, but this was consistent with previously reported incidences in healthy volunteers without apparent heart disease. AIM To evaluate the effect of eltrombopag on cardiac repolarization and to characterize the relationship between plasma eltrombopag concentrations and change in QTc. METHODS This was a double-blind, placebo- and active-controlled, randomized, balanced four-period, crossover study in healthy men and women. Subjects were randomized to receive eltrombopag 50 mg and 150 mg, moxifloxacin 400 mg (positive control) and placebo in one of four sequences. RESULTS Eighty-seven subjects entered the study and 48 completed. There was no prolongation of QTc (Fridericia) following eltrombopag treatment, as the upper limit of the 90% confidence interval (CI) for the time-matched change from baseline in QTcF between drug and placebo (ddQTcF) did not exceed 10 ms for eltrombopag at either dose. Maximum observed mean treatment difference was 2.29 ms (90% CI 0.34, 4.24) for eltrombopag 150 mg at 1 h post-dose and 11.64 ms (90% CI 9.64, 13.64) for moxifloxacin 400 mg at 4 h. Eltrombopag Cmax and AUC(0,24 h) increased in a dose proportional manner between 50 mg and 150 mg after 5 days' dosing. Proportions of subjects with adverse events were similar across treatments (52–66% of subjects). Most withdrawals (26/39 subjects) were due to elevated platelets. Three subjects were withdrawn for ventricular premature beats (one following each active treatment) reported as related to the study drug. CONCLUSIONS No clinically significant QTc prolongation was observed for eltrombopag at therapeutic and supratherapeutic doses. [ABSTRACT FROM AUTHOR]

Abstract: Rock joints were numerically simulated, and an extensive series of direct shear tests were carried out using the code PFC3D. The feasibility of reproducing a rock joint using the contact bond model was demonstrated, and the effects of the geometrical features and the micro-properties of a joint on its shear behavior were examined. Asperity failure was observed from the micro-cracks and contact force distribution, as well as the stresses and displacements in shear and normal directions. A rough joint with a joint roughness coefficient (JRC) value ranging from 10 to 20 was produced in an intact sample by defining the joint-contacts along a predefined joint surface. To simulate a decrease in joint wall strength (JCS) caused by weathering and alterations, the bond strength between particles involved in the joint-contacts was reduced by up to 70%. The shear behavior and failure progress at a given stress corresponded well to those observed in laboratory tests. The friction coefficient was the most important factor governing the shear strength and dilation angle. The variation in joint roughness and contact bond strength had a larger effect on the cohesion than peak friction angle. In addition, a new approach to represent JRC and JCS values of a joint was proposed for practical use. A numerical 3D-profile scanning technique was developed to evaluate the actual JRC of the simulated joint, and the relationship between the JCS and the contact bond strength was investigated. [Copyright &y& Elsevier]

Abstract: This paper describes the nonlinear parameter optimization of power system stabilizer (PSS) by using the reduced multivariate polynomial (RMP) algorithm with the one-shot property. The RMP model estimates the second-order partial derivatives of the Hessian matrix after identifying the trajectory sensitivities, which can be computed from the hybrid system modeling with a set of differential-algebraic-impulsive-switched (DAIS) structure for a power system. Then, any nonlinear controller in the power system can be optimized by achieving a desired performance measure, mathematically represented by an objective function (OF). In this paper, the output saturation limiter of the PSS, which is used to improve low-frequency oscillation damping performance during a large disturbance, is optimally tuned exploiting the Hessian estimated by the RMP model. Its performances are evaluated with several case studies on both single-machine infinite bus (SMIB) and multi-machine power system (MMPS) by time-domain simulation. In particular, all nonlinear parameters of multiple PSSs on IEEE benchmark two-area four-machine power system are optimized to be robust against various disturbances by using the weighted sum of the OFs. [Copyright &y& Elsevier]

One of the most frequently used methods to model the autocovariance function of a second-order stationary time series is to use the parametric framework of autoregressive and moving average models developed by Box and Jenkins. However, such parametric models, though very flexible, may not always be adequate to model autocovariance functions with sharp changes. Furthermore, if the data do not follow the parametric model and are censored at a certain value, the estimation results may not be reliable. We develop a Gaussian imputation method to estimate an autocovariance structure via nonparametric estimation of the autocovariance function in order to address both censoring and incorrect model specification. We demonstrate the effectiveness of the technique in terms of bias and efficiency with simulations under various rates of censoring and underlying models. We describe its application to a time series of silicon concentrations in the Arctic. [ABSTRACT FROM AUTHOR]

This paper focuses on the systematic optimal tuning of the power system stabilizer (PSS), which can improve, the system damping performance immediately following a large disturbance. As the PSS consists of both linear parameters (such as the gain and time constant) and nonsmooth nonlinear parameters (such as saturation limits of the PSS), two methods are applied for the optimal tuning of all parameters. One is to use the optimization technique based on the Hessian matrix estimated by the feedforward neural network, which identifies the first-order derivatives obtained by the trajectory sensitivities, for the nonlinear parameters. Moreover, the other is to use the eigenvalue analysis for the linear parameters. The performances of parameters optimized by the proposed method are evaluated by the case studies based on time-domain simulation and real-time hardware implementation. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the design of an infinite horizon nonlinear optimal neurocontroller that replaces the conventional automatic voltage regulator and the turbine governor (CONVC) for the control of a synchronous generator connected to an electric power grid. The neurocontroller design uses the novel optimization neuro-dynamic programming algorithm based on dual heuristic programming (DHP), which has the most robust control capability among the adaptive critic designs family. The radial basis function neural network (RBFNN) is used as the function approximator to implement the DHP technique. The DHP based optimal neurocontroller (DHPNC) using the RBFNN shows improved dynamic damping compared to the CONVC even when a power system stabilizer is added. Also, the DHPNC provides a robust feedback loop in real-time operation without the need for continual on-line training, thus reducing any risk of possible instability associated with the neural network based controllers. [Copyright &y& Elsevier]

Abstract: This paper proposes a data cache with small space for low power, but high performance on multimedia applications. The basic architecture is a split-cache consisting of a direct-mapped cache with small block size (DMC) and a fully-associative buffer with large block size (FAB). To overcome the disadvantage caused by small cache areas, two hardware mechanisms are enhanced considering the operational behaviors of multimedia applications: an adaptive multi-block prefetching to initiate various fetch sizes for FAB and an efficient block filtering to remove the data likely to be rarely reused for DMC. The simulations on MediaBench show that the proposed 5kB cache can achieve up to 57% and 50% of power saving while providing almost equal and better performance compared with the 16kB 4-way set associative cache and 17kB stream caches, respectively. [Copyright &y& Elsevier]

nalyse de séries chronologiques censurées au moyen de modèles autorégressifs à moyenne mobile Les auteurs s'intéressent à des séries chronologiques dont certaines observations sont censurées lorsqu'elles dépassent un certain seuil. Règle générale, les praticiens ne tiennent pas compte des cas de censure, ce qui induit souvent un biais d'estimation. Les auteurs présentent une façon élégante de traiter des données autocorrélées censurées au moyen d'une classe de modèles autorégressifs à moyenne mobile (ARMA). En particulier, ils proposent une méthode d'imputation bien adaptée à l'ajustement de modèles ARMA en présence de censure. Ils démontrent la bonne performance de leur technique aux plans du biais, de l'efficacité et de la perte d'information. Ils montrent aussi comment elle peut être adaptée au contexte spécifique de données météorologiques temporelles sur la hauteur du plafond nuageux, dont l'évaluation est limitée par la capacité de l'instrument de mesure. [ABSTRACT FROM AUTHOR]

Abstract: This research is to design a low power set-associative cache for embedded processors without additional delay or performance degradation. For this goal, deterministic way selection logic with power-aware replacement policy is designed to enable only one way of set-associative cache as in the direct-mapped cache. Delay analysis shows that the cache access time is almost the same as that of conventional set associative cache with additional way selection logic. Proposed architecture exploits the trade-offs between power and performance to achieve power reduction with the least performance loss. As the result of those approaches, simulation shows that the proposed architecture can reduce unit accessing power consumption by 59% over conventional set-associative caches with average 0.06% of negligible performance loss. [Copyright &y& Elsevier]

Abstract: Study Objective: The aim of this study was to compare the volume and the pH level of preoperative gastric contents and serum gastrin concentrations between pregnant and nonpregnant women. Design: This prospective controlled study was conducted in a single blind manner. Patients: One hundred pregnant women scheduled for elective cesarean delivery (pregnant group) and 100 nonpregnant women who underwent gynecologic surgery (nonpregnant group) were enrolled. Interventions: Gastric content was aspirated gently with 14-F multiorificed nasogastric tube before the induction of anesthesia. Measurements: The volume and the pH level of the aspirated gastric contents were measured, and serum gastrin concentration was measured by the double antibody gastrin method. Main Results: The gastric volume in the pregnant group was greater than in the nonpregnant group (0.49 ± 0.4 vs 0.24 ± 0.2 mL/kg, P < .05). The gastric pH level in the pregnant group was lower than in the nonpregnant group (2.4 ± 1.4 vs 3.0 ± 1.9, P < .05). The number of patients at risk was 45 (45.5%) in the pregnant group and 16 (16.7%) in the nonpregnant group (P < .05). The serum gastrin levels of the 2 groups were not significantly different (32.1 ± 12.3 vs 28.2 ± 8.3 pg/mL). The preoperative anxiety level of the pregnant group was higher than in the nonpregnant group (4.4 ± 2.1 vs 3.8 ± 2.2, P < .05). Conclusions: We confirmed that pregnant women have much greater and more acidic gastric contents than the nonpregnant patients preoperatively, and it is not because of serum gastrin concentration. [Copyright &y& Elsevier]

Abstract: In this paper, the dual heuristic programming (DHP) optimization algorithm is applied for the design of two LOCAL nonlinear optimal neuro-controllers on a practical multi-machine power system. One neuro-controller is designed to replace the conventional linear controllers, which are the automatic voltage regulator (AVR) and speed-governor (GOV), for a synchronous generator. The other is a new external neuro-controller for the series capacitive reactance compensator (SCRC), flexible ac transmission systems (FACTS) device. The PSCAD/EMTDC® simulation results show that interactions of two DHP neuro-controllers with different control objectives improve the system performance more effectively compared to when each one operates without the presence of the other one. [Copyright &y& Elsevier]

The controllable capacitive reactance can be used as the input variable for the external controller of a series capacitive reactance compensator (SCRC) to improve the damping of low, frequency oscillations of the rotor angle and active power in a power system. Conventional linear PI controllers are tuned for best performance at one specific operating point of the nonlinear power system. At other operating point its performance degrades. Nonlinear optimal neuro-controllers are able to overcome this degradation. In this paper, the dual heuristic dynamic programming (PUP) optimization algorithm is applied to design an external nonlinear optimal neuro-controller for the SCRC. Simulation studies using PSCAD/EMTDC® software are presented. [ABSTRACT FROM AUTHOR]

In this paper, the proportional-integral (PI) based conventional internal controller (CONVC) of a power electronic based series compensator in an electric power system, is replaced by a nonlinear optimal controller based on the dual heuristic programming (DHP) optimization algorithm. The performance of the CONVC is compared with that of the DHP controller with respect to damping low frequency oscillations. Simulation results using the PSCAD/EMTDC software package are presented. [Copyright &y& Elsevier]

The smart inverter (SI) is an emerging technology, which enables the effective integration of distributed energy resources (DERs). Nevertheless, the operation by the only single SI function is not sufficient to deal with various conditions in a distribution system. In other words, all DERs are required to rapidly update the proper mode of SI functions depending on the system conditions. In this article, we propose the new active distribution management system (ADMS) for photovoltaic (PV)/energy storage system (ESS) integrated system based on the SI functions. It effectively regulates the system voltage, and it solves the line congestion problem in a distribution system by adaptively controlling the mode of SI functions. This method enables DER to effectively regulate its generation without the additional controllers. The effectiveness of the proposed ADMS is verified by several case studies on a practical distribution system in South Korea with the real measurements of generation from PV and load consumption based on the electromagnetic transient program. Also, the PV/ESS integrated system prototype of 100 kW is implemented for the experimental verification of the proposed ADMS. [ABSTRACT FROM AUTHOR]

Background: Since severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) was first reported in Wuhan, China, in December 2019, it has spread rapidly, and many coronavirus disease (COVID‐19) cases have occurred in Gwangju, South Korea. Viral mutations following the COVID‐19 epidemic have increased interest in the characteristics of epidemics in this region, and pathogen genetic analysis is required for infection control and prevention. Methods: In this study, SARS‐CoV‐2 whole‐genome analysis was performed on samples from patients with COVID‐19 in Gwangju from 2020 to 2022 to identify the trends in COVID‐19 prevalence and to analyze the phylogenetic relationships of dominant variants. B.41 and B.1.497 prevailed in 2020, the early stage of the COVID‐19 outbreak; then, B.1.619.1 mainly occurred until June 2021. B.1.617.2, classified as sublineages AY.69 and AY.122, occurred continuously from July to December 2021. Since strict measures to strengthen national quarantine management had been implemented in South Korea until this time, the analysis of mutations was also able to infer the epidemiological relationship between infection transmission routes. Since the first identification of the Omicron variant in late December 2021, the spread of infection has been very rapid, and weekly whole‐genome analysis of specimens has enabled us to monitor new Omicron sublineages occurring in Gwangju. Conclusions: Our study suggests that conducting regional surveillance in addition to nation‐level genomic surveillance will enable more rapid and detailed variant surveillance, which will be helpful in the overall prevention and management of infectious diseases. [ABSTRACT FROM AUTHOR]

The symmetry reduction of molecular shape of cationic chromophores as a design strategy to develop organic terahertz (THz) generators is used. Electron donating group (EDG) with an asymmetric shape is introduced into two types of cationic styryl‐quinolinium chromophores, leading to the development of several novel non‐centrosymmetric crystals with high macroscopic optical nonlinearity. In contrast, when an EDG with a symmetric shape is introduced, centrosymmetric crystal structure is obtained in all investigated crystals. For THz wave generation, crystals based on asymmetrically shaped EDG exhibit several optimal crystal characteristics, including a plate‐shape morphology, a large size, and an in‐plane polar axis. Furthermore, over the entire range of molecular phonon vibrations, 0.5–4 THz, the steric hindrance group in the asymmetrically shaped EDG has a strong influence on the suppression of THz phonon vibrations, leading to a low THz absorption coefficient. The crystals based on asymmetrically shaped EDG generate an ≈40 times stronger THz electric field than the inorganic ZnTe crystal and very broad THz spectra, extending up to 16 THz. Thus, the symmetry reduction of the molecular shape of cationic chromophores through the introduction of an asymmetrically shaped EDG is an effective design approach for the development of novel organic THz crystals. [ABSTRACT FROM AUTHOR]

The present study is aimed at developing a numerical model to reproduce coupled hydro-mechanical processes associated with fault reactivation by fluid injection in low permeability rock, as part of the DECOVALEX-2019 project Task B. We proposed a modeling approach for simulating the processes using the TOUGH-FLAC simulator, and modeled a fault reactivation experiment conducted at Mont Terri Rock Laboratory in Switzerland. The first step of the study involved benchmark calculations considering a simplified fault plane and geometry. Fluid flow along a fault was modeled using elements of aperture-sized thickness on the basis of Darcy's law and the cubic law in TOUGH2, whereas the mechanical behavior of a single fault was represented by zero-thickness interface elements in FLAC3D upon which a slip and/or separation is allowed. A methodology to connect a TOUGH2 volume element to a FLAC3D interface element was developed for handling the hydro-mechanical interactions on the fault during fluid injection. Two different fault models for describing the evolutions of hydraulic aperture by elastic fracture opening and failure-induced aperture increase were considered in the benchmark calculations. In the coupling process, the changes in geometrical features and hydrological properties induced by mechanical deformation were continuously updated. The transient responses of the fault and host rock to stepwise pressurization were examined during the simulation. The hydro-mechanical behavior, including the injection flow rate, pressure distribution around the borehole, stress conditions, and displacements in normal and shear directions were monitored in the surrounding rock and along the fault. The results of benchmark calculations suggest that the developed model reasonably represents the hydro-mechanical behavior of a fault and the surrounding rock. This modeling approach was applied to the fault reactivation experiment of the Mont Terri Rock Laboratory. In this interpretive modeling, a parametric study was conducted to examine the effects of input parameters regarding in situ stress and fault properties on the hydro-mechanical responses of the fault to water injection. Then, an optimal parameter set to reproduce the field experiment results was chosen by trial-and-error. The injection flow rate and pressure response during fault reactivation closely matched those obtained at the site, which indicates the capability of the model to appropriately capture the progressive pathway evolution during fault reactivation tests at the site. The anchor displacements were overestimated by the model, but a fair agreement was obtained in terms of the order of magnitude and the variation tendency. • We propose a modeling approach for fault activation using TOUGH-FLAC simulator. • Dual simulation of fault elements overcomes inherent problems from each method. • The model reasonably reproduces fault failure process and pathway evolution. [ABSTRACT FROM AUTHOR]

As renewable energy penetrates the power system, system operators are required to curtail output power from generation units to balance the power supply and demand. However, large curtailment from wind power plants (WPPs) may instantly cause excessive output power decrement, causing system frequency to drop significantly before reaching its nominal value. In order to solve this problem, this paper proposes a cooperative control framework to determine the operation of WPPs in two control methods, which are the stepwise inertial control (SIC) method and the curtailed control method. The proposed framework first determines the WPPs to operate in the curtailed control method to provide the required power curtailment. Next, it determines the WPPs to operate in the SIC method considering their releasable kinetic energy to provide an effective inertial response and compensate for the sudden excessive output power decrement caused by other WPPs operated in the curtailed control method. Therefore, each WPP is operated in one of two control methods to provide required power curtailment while reducing the sudden excessive output power decrement. To verify the effectiveness of the proposed cooperative control framework, several case studies are carried out on the practical South Korea electric power system. [ABSTRACT FROM AUTHOR]

The fire growth rate index (FIGRA), which is the ratio of the maximum value of the heat release rate (Qmax) and the time (tmax) to reach the maximum heat release rate, is a general method to evaluate a material in the fire-retardant performance in fire technology. The object of this study aims to predict FIGRA of the polyethylene foam pipe insulation in accordance with the scale factor (Sf), the volume fraction of the pipe insulation (VF) and the ignition heat source (Qig). The compartments made of fireboard have been mock-up with 1/3, 1/4, and 1/5 reduced scales of the compartment as specified in ISO 20632. The heat release rate data of the pipe insulation with the variation of Sf, VF, and Qig are measured from 33 experiments to correlate with FIGRA. Based on a critical analysis of the heat transfer phenomenon from previous research literature, the predictions of Qmax and tmax are presented. It is noticeable that the fire-retardant grade of the polyethylene foam pipe insulation could have Grade B, C, and D in accordance with the test conditions within ±15% deviation of the predicted FIGRA. In case of establishing the database of various types of insulation, the prediction models could apply to evaluate the fire-retardant performance. [ABSTRACT FROM AUTHOR]

This study investigated the prevalence of Orientia tsutsugamushi, Anaplasma phagocytophilum, and Leptospira interrogans in wild rodents through molecular detection using organ samples and through serological assay using blood samples of mice collected from two distinct sites in Gwangju Metropolitan City, Republic of Korea (ROK). A total of 47 wild rodents, identified as Apodemus agrarius (A. agrarius), were captured from June to August 2016. The seroprevalence of antibodies against bacterial pathogens in A. agrarius sera was analyzed; 17.4% (8/46) were identified as O. tsutsugamushi through indirect immunofluorescence assay and 2.2% (1/46) were identified as Leptospira species through passive hemagglutination assay. Using polymerase chain reaction, the spleen, kidney and blood samples were investigated for the presence of O. tsutsugamushi, A. phagocytophilum, and L. interrogans. Out of the 47 A. agrarius, 19.1% (9/47) were positive for A. phagocytophilum and 6.4% (3/47) were positive for L. interrogans, while none were positive for O. tsutsugamushi. Four out of 46 (8.7%) blood samples, six out of 45 (13.3%) spleen samples, and one out of 47 (2.1%) kidney samples were positive for A. phagocytophilum. Three out of 47 (6.4%) kidney samples were positive for L. interrogans. The sequencing results of PCR positive samples demonstrated > 99% similarity with A. phagocytophilum and L. interrogans sequences. A. phagocytophilum was mostly detected in the spleen, whereas L. interrogans was mostly detected in the kidneys. Notably, A. phagocytophilum and L. interrogans were detected in A. agrarius living in close proximity to humans in the metropolitan suburban areas. The results of this study indicate that rodent-borne bacteria may be present in wild rodents in the metropolitan suburban areas of ROK. [ABSTRACT FROM AUTHOR]

In South Korea, the stand-alone microgrid on an island has synchronous diesel generators and multiple distributed generations (DG) based on renewable energy, and energy storage systems (ESS). According to the active policy of government to develop eco-friendly microgrids with zero carbon emission, many diesel generators in stand-alone microgrids are being replaced by the DGs. It brings challenges on the operation and control of multiple DGs because this causes the lack of inertia, which is originally provided from the diesel generators. [ABSTRACT FROM AUTHOR]

This paper proposes the new clamping angle control (CAC) pulse width modulation (PWM) method to restore its maximum linear modulation range of voltage source inverters (VSIs) reduced by the duty ratio limitation in hardware implementation, which makes the VSIs to operate nonlinearly in the high modulation range. The deadtime and the bootstrap gate driver circuit mainly cause this duty ratio limitation in practice. In particular, the bootstrap gate driver circuit is used in many industrial applications by avoiding the additional power supply to apply the gate-source voltage of power switches, and therefore making the VSIs to be small size with the low cost. First, the proposed CACPWM method is theoretically analyzed. Then, it is applied in the high modulation range to overcome the limitation of the duty ratio due to the use of the bootstrap gate driver circuit. Thereafter, its practical effectiveness is verified by both simulation and experimental tests. Also, the resulting harmonic distortions are compared with those by the conventional PWM methods. [ABSTRACT FROM AUTHOR]

The inertia-free stand-alone (IFSA) microgrid is the new small power grid without synchronous generators equipped in conventional power systems. In other words, this system has the only converter-based generators (CBGs) based on energy storage devices and renewable energies. Therefore, it requires a new CBG control to provide strong voltage reference for the CBGs connected to the point of common coupling (PCC). This is because the IFSA microgrid is subject to a weak system such that it cannot maintain its rated frequency and/or bus voltage with the conventional real and reactive power controllers, which usually get their references from the PCC. This paper proposes the innovative conceptual approach for distributed coordination in the IFSA microgrid by applying the synchronized global positioning system time to the CBGs. Moreover, it is verified that the proposed physical structure of the IFSA microgrid makes it possible for all CBGs to share the real and reactive powers effectively. As the result, the proposed CBG control can provide the robustness, which is strongly required in the IFSA microgrid, based on timely outage management and restoration process. Several case studies are carried out with the microgrid of 36 MW to verify the effectiveness of the proposed CBG controller. The simulation and hardware-in-the loop tests are carried out using the power system computer-aided design/electromagnetic transient design and control (PSCAD/EMTDC) and the real-time digital power system simulator (RTDS), respectively. [ABSTRACT FROM AUTHOR]

The kinetic energy stored in the rotating mass of wind turbine generators can provide the effective power quality solution to the inertia-free stand-alone (IFSA) microgrid by improving its stability. In conventional power systems, the power released from the inertia of synchronous generators regulates the system frequency. However, the frequency does not vary much even when a large disturbance or a load change occurs in the IFSA microgrid with only converter-based generators. This paper proposes a new inertia control method for a type-4 permanent magnet synchronous generator wind turbine system in the IFSA microgrid by utilizing the measurement of the dc-link voltage of the converter and its derivatives, not by the system frequency. Several case studies are carried out to evaluate the performance of the proposed inertia control in the IFSA microgrid with electromagnetic transients program-based simulation. Also, its effectiveness is verified with the experimental results from the hardware-in-the-loop test implemented by the controller interface with the digital signal processor, which is connected to the real-time digital simulator. [ABSTRACT FROM AUTHOR]

Zolbetuximab, a monoclonal antibody targeting claudin-18 isoform 2 (CLDN18.2), has shown efficacy in patients with CLDN18.2-positive, human epidermal growth factor receptor 2 (HER2)-negative, locally advanced unresectable or metastatic gastric or gastro-oesophageal junction adenocarcinoma. We report the results of the SPOTLIGHT trial, which investigated the efficacy and safety of first-line zolbetuximab plus mFOLFOX6 (modified folinic acid [or levofolinate], fluorouracil, and oxaliplatin regimen) versus placebo plus mFOLFOX6 in patients with CLDN18.2-positive, HER2-negative, locally advanced unresectable or metastatic gastric or gastro-oesophageal junction adenocarcinoma. SPOTLIGHT is a global, randomised, placebo-controlled, double-blind, phase 3 trial that enrolled patients from 215 centres in 20 countries. Eligible patients were aged 18 years or older with CLDN18.2-positive (defined as ≥75% of tumour cells showing moderate-to-strong membranous CLDN18 staining), HER2-negative (based on local or central evaluation), previously untreated, locally advanced unresectable or metastatic gastric or gastro-oesophageal junction adenocarcinoma, with radiologically evaluable disease (measurable or non-measurable) according to Response Evaluation Criteria in Solid Tumors version 1.1; an Eastern Cooperative Oncology Group performance status score of 0 or 1; and adequate organ function. Patients were randomly assigned (1:1) via interactive response technology and stratified according to region, number of organs with metastases, and previous gastrectomy. Patients received zolbetuximab (800 mg/m2 loading dose followed by 600 mg/m2 every 3 weeks) plus mFOLFOX6 (every 2 weeks) or placebo plus mFOLFOX6. The primary endpoint was progression-free survival assessed by independent review committee in all randomly assigned patients. Safety was assessed in all treated patients. The study is registered with ClinicalTrials.gov , NCT03504397 , and is closed to new participants. Between June 21, 2018, and April 1, 2022, 565 patients were randomly assigned to receive either zolbetuximab plus mFOLFOX6 (283 patients; the zolbetuximab group) or placebo plus mFOLFOX6 (282 patients; the placebo group). At least one dose of treatment was administered to 279 (99%) of 283 patients in the zolbetuximab group and 278 (99%) of 282 patients in the placebo group. In the zolbetuximab group, 176 (62%) patients were male and 107 (38%) were female. In the placebo group, 175 (62%) patients were male and 107 (38%) were female. The median follow-up duration for progression-free survival was 12·94 months in the zolbetuximab group versus 12·65 months in the placebo group. Zolbetuximab treatment showed a significant reduction in the risk of disease progression or death compared with placebo (hazard ratio [HR] 0·75, 95% CI 0·60–0·94; p=0·0066). The median progression-free survival was 10·61 months (95% CI 8·90–12·48) in the zolbetuximab group versus 8·67 months (8·21–10·28) in the placebo group. Zolbetuximab treatment also showed a significant reduction in the risk of death versus placebo (HR 0·75, 95% CI 0·60–0·94; p=0·0053). Treatment-emergent grade 3 or worse adverse events occurred in 242 (87%) of 279 patients in the zolbetuximab group versus 216 (78%) of 278 patients in the placebo group. The most common grade 3 or worse adverse events were nausea, vomiting, and decreased appetite. Treatment-related deaths occurred in five (2%) patients in the zolbetuximab group versus four (1%) patients in the placebo group. No new safety signals were identified. Targeting CLDN18.2 with zolbetuximab significantly prolonged progression-free survival and overall survival when combined with mFOLFOX6 versus placebo plus mFOLFOX6 in patients with CLDN18.2-positive, HER2-negative, locally advanced unresectable or metastatic gastric or gastro-oesophageal junction adenocarcinoma. Zolbetuximab plus mFOLFOX6 might represent a new first-line treatment in these patients. Astellas Pharma, Inc. [ABSTRACT FROM AUTHOR]

Fanconi anemia (FA) patients are highly susceptible to solid tumors at multiple anatomical sites including head and neck region. A subset of head and neck cancers (HNCs) is associated with ‘high-risk’ HPVs, particularly HPV16. However, the correlation between HPV oncogenes and cancers in FA patients is still unclear. We previously learned that FA deficiency in mice predisposes HPV16 E7 transgenic mice to HNCs. To address HPV16 E6’s oncogenic potential under FA deficiency in HNCs, we utilized HPV16 E6-transgenic mice (K14E6) and HPV16 E6/E7-bi-transgenic mice (K14E6E7) on genetic backgrounds sufficient or deficient for one of the fanc genes, fancD2 and monitored their susceptibility to HNCs. K14E6 mice failed to develop tumor. However, E6 and fancD2-deficiency accelerated E7-driven tumor development in K14E6E7 mice. The increased tumor incidence was more correlated with E7-driven DNA damage than proliferation. We also found that deficiency of pocket proteins, pRb, p107, and p130 that are well-established targets of E7, could recapitulate E7’s induction of DNA damage. Our findings support the hypothesis that E7 induces HPV-associated HNCs by promoting DNA damage through the inactivation of pocket proteins, which explains why a deficiency in DNA damage repair would increase susceptibility to E7-driven cancer. Our results further demonstrate the unexpected finding that FA deficiency does not predispose E6 transgenic mice to HNCs, indicating a specificity in the synergy between FA deficiency and HPV oncogenes in causing HNCs. [ABSTRACT FROM AUTHOR]

This paper proposes a computationally effective method for optimal operation of multiple distributed generations (DGs) in dc distribution systems to improve their efficiency. There have been many research works to select the optimal sizes of multiple DGs. However, these optimal sizes are valid only in the particular operating point. For optimal operations of power systems, the DG sizes must be determined all the time according to the various load conditions. The proposed method can maintain the distribution system operating in its optimal condition with only single optimization process, without regard to load variations. Therefore, it can moderate the serious problems, derived from inaccurate load forecasting. To verify the performance of the proposed method, the dc system is first implemented with the real distribution system of Do-gok area in Seoul, Korea. Then, the real hourly-load data, acquired from SCADA system in Korea, are used to simulate the practical load variations. [ABSTRACT FROM PUBLISHER]

To enhance performance of flash memory-based solid state disk (SSD), large logically chained blocks can be assembled by binding adjacent flash blocks across several flash memory chips. However, flash memory does not allow in-place overwriting and thus the operations that merge writes on these blocks suffer a visible decrease in performance. Furthermore, when small random writes are spread over the disk address space, performance tends to be degraded significantly. We thus present a technique to manage random writes efficiently to achieve stable SSD performance. In this paper, we propose a pattern adaptive SSD structure, which classifies access patterns as either random or sequential. The structure primarily consists of a write cache and a flash translation layer that separates groups of writes by access pattern (S-FTL). Separately managing the two types of write patterns enables greater parallelism and reduces the cost of large block management, thus enhancing the performance of the proposed SSD. Simulation experiments show that the proposed pattern adaptive structure can provide 39 percent decrease in extra flash block erase overhead on the average, and write performance can be improved by around 60 percent, compared with a basic FTL applied to existing parallel SSD structures. [ABSTRACT FROM AUTHOR]

Like conventional two-switch leg converters, the three-switch leg converters also have short-circuit risks and a dangerous shoot-through current is generated if switches of the same leg are turned on simultaneously. In this article, a new dual-buck structure is proposed for three-switch leg converters. The proposed structure is reliable because of no shoot-through concerns and high quality of output waveforms can be obtained due to the reduction in pulsewidth modulation deadtime. Unlike the conventional dual-buck three-switch leg that uses many passive components such as four current limiting inductors and three external diodes, the new dual-buck three-switch leg uses only one current limiting inductor with two external diodes. To verify the performance, the proposed three-switch legs are used in single-phase dual-output inverter and detailed theoretical analysis, simulation, and experiments are performed. Both continuous and discontinuous modulation schemes are applied and it has been figured out that discontinuous modulation scheme can improve the dc-link voltage utilization in the common-frequency mode of operation. [ABSTRACT FROM AUTHOR]

We developed a geothermal monitoring system with an open-source Internet of Things (IoT) system. The study's objective is to achieve an economical alternative solution to the expensive commercial data loggers, local PC-based control, data storage limitation, the number of sensor connections, and secure data transmission over the Internet in a decentralized renewable energy system. The developed system consists of hardware and software customized with open-source support that helps resolve the conventional limitations that the commercial system inherently has. We have applied the system to a geothermal energy system deployed at a residential care facility for the elderly in Chuncheon, South Korea. The proposed system enabled us to acquire the data of temperature and fluid flow in real-time and for a prolonged period (i.e., years) at an affordable price compared to installing a conventional data-acquisition system. The real-time multi-year-long data helped confirm seasonality in heating and cooling. We can also apply the same proposed system to the other renewable energy systems monitoring temperature, pressure, wind speed, displacement, noise, seismicity, etc. • Development of a geothermal monitoring system with an open-source IoT system. • The system was applied to a geothermal system deployed at a residential care facility. • The real-time multi-year-long data helped confirm seasonality in heating and cooling. • We can also apply the same proposed system to the other renewable energy. [ABSTRACT FROM AUTHOR]

Background: Hemorrhagic fever with renal syndrome (HFRS) caused by hantaviruses is a frequently reported acute hemorrhagic fever in South Korea. These viruses are transmitted by various rodent species such as Apodemus agrarius. Methodology/Principal findings: To investigate hantavirus infection and seroprevalence in rodents, wild rodents were captured from two districts in the suburbs of Gwangju Metropolitan City from January 2016 to December 2018. Nested reverse-transcription polymerase chain reaction (RT-PCR) targeting the hantavirus-specific L segment and indirect immunofluorescence antibody (IFA) assay using Hantaan virus antigen slides were performed. A total of 585 wild rodents were captured—512 A. agrarius, 49 Crocidura lasiura, and 24 Myodes regulus. Nested RT-PCR was performed to examine the rate of hantavirus infection in wild rodents, and 1.88% (11/585) of all rodents, 1.17% (6/512) of A. agrarius, 6.12% (3/49) of C. lasiura, and 8.33% (2/24) of M. regulus tested positive. The nucleotide sequence analysis of the eleven PCR-positive products revealed that six PCR products showed over 85% sequence similarity with the Jeju virus, four showed over 99.7% similarity with the Hantaan virus, and one showed over 95.3% homology with the Imjin virus. Moreover, IgG antibodies against the Hantaan virus were detected in 6.15% (36/585) of all rodents, 6.8% (35/512) of A. agrarius, and 4.17% (1/24) of M. regulus. IgG antibodies were not detected in C. lasiura. Conclusions/Significance: Hantaviruses were detected in all three wild rodent species of A. agrarius, C. lasiura, and M. regulus captured in the suburbs of Gwangju Metropolitan City, South Korea, and it was demonstrated that they were various strains of hantaviruses such as the Hantaan, Jeju, and Imjin viruses. Author summary: Hantaviruses (family Hantaviridae, genus Hantavirus) are rodent viruses that can cause two fatal human diseases—hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. These viruses are transmitted by various rodent species such as Apodemus agrarius. In the present study, wild rodents captured in the suburbs of Gwangju Metropolitan City were analyzed by nested reverse-transcription polymerase chain reaction targeting the hantavirus-specific L segment and indirect immunofluorescence antibody assay using Hantaan virus antigen slides. A total of 585 wild rodents were captured and 1.88% (11/585) of all rodents, 1.17% (6/512) of A. agrarius, 6.12% (3/49) of Crocidura lasiura, and 8.33% (2/24) of Myodes regulus were PCR-positive. Of the eleven PCR-positive wild rodents, six PCR products showed over 85% sequence similarity with the Jeju virus, four showed over 99.7% similarity with the Hantaan virus, and one showed over 95.3% homology with the Imjin virus. Moreover, IgG antibodies against the Hantaan virus were detected in 6.15% (36/585) of all rodents, 6.8% (35/512) of A. agrarius, and 4.17% (1/24) of M. regulus. IgG antibodies were not detected in C. lasiura. When we examined the detection rate of hantavirus genes in different seasons, hantaviruses were most commonly detected in fall (seven cases [5.69%]) and winter (four cases [2.76%]). No hantaviruses were detected in spring or summer. However, the seasonal prevalence of IgG antibodies was higher in spring and summer (12 [7.32%] and 11 [7.10%] cases, respectively) than in fall and winter (seven [5.69%] and six [4.14%] cases, respectively). This study was performed on a monthly basis throughout a three-year period, and thus, it provides reliable data that may provide insight into preventive measures against HFRS. Our results suggest that various types of hantaviruses, including Hantaan, Jeju, and Imjin viruses, are distributed throughout Gwangju Metropolitan City, South Korea. Data regarding the rate of Hantaan virus infection in rodents in Gwangju and knowledge of the hantavirus seroprevalence, species, and genotypes circulating in these domestic rodent species will provide useful information for developing vaccines and diagnostic testing using sequence data. These will help increase preparedness for the emergence of new species. [ABSTRACT FROM AUTHOR]

This paper describes a power management method in a feeder with distributed generations (DGs) and energy storage devices. To ensure stability, reliability, and safety of the system, the proposed power management method deals with the DGs in two groups, which are utility and independent power producer (IPP). When the feeder is islanded from grid, the utility-owned DG receives fault signal from the protection relay. Thereafter, it is allowed to operate itself when the feeder is islanded because it is directly controlled by the utility. In contrast, the IPP-owned DG should be stopped to avoid several problems, which can be caused by the islanding operation. Then, the proposed power management method operates the above DGs to maximize the efficiency with no serious impact to grid. To do so, the inverter controller of DG is designed to implement it in a part of practical distribution system, which is located at the Do-gok area in Seoul, Korea. Several case studies are carried out to verify the effectiveness of proposed method. [ABSTRACT FROM PUBLISHER]