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The medical device industry is an industry dealing with multiple types of products covering a wide range of applications. As the safety and effectiveness of medical devices are vital to human health, the products must be managed by strict regulations according to the different risk levels. A total product life cycle regulatory system including product design, manufacture, premarket gate keeping, and postmarket monitoring is a common framework for medical device regulations. However, the variety and innovativeness of medical devices are challenging the current regulatory frameworks. Hence, the competent authorities responsible for medical devices worldwide keep renewing their regulatory systems to ensure the safety and effectiveness of medical devices. This review aims to provide an informative review of the regulatory frameworks of medical devices in the United States, Europe, Canada, and Taiwan, with a particular focus on updated regulatory changes in these countries and the current status of global harmonization on medical devices.

This study examines the influence of corporate control on the appointment and quality characteristics of independent directors. Our findings, based upon a dataset of related appointments within listed companies in Taiwan, suggest that the preferences of firms to voluntarily appoint independent directors has a positive association with the control right of the controlling shareholder, stemming from the cash flow rights, not from the deviation between ownership and control after decomposing the control. Most importantly, we find that the firms with high control right and cash flow rights of the controlling shareholders are likely to voluntarily appoint independent directors with good auditing expertise and reputation.

This study examines the incremental information content of components of earnings by regressing future net income of earnings¡¯ components in a series of multivariate models. We find that the components of operating cash flow and accruals provide more information to effectively predict future profitability, particularly when we dismantles financial measurements into various combinations of operating cash flow and accrual-based components. However, the components of real earnings management provide less information of future profitability. We observe that the more informative the information content of earnings is, the more precise the prediction of future profitability can be.

Objective To describe and compare diffusion tensor imaging (DTI) parameters between patients with subcortical ischemic vascular disease (SIVD) and Alzheimer’s disease (AD) diagnosed using structuralized neuropsychiatric assessments, and investigate potential neuronal substrates related to cognitive performance. Methods Thirty-five patients with SIVD, 40 patients with AD, and 33 cognitively normal control (NC) subjects matched by age and education level were consecutively recruited and underwent cognitive function assessments and DTI examinations. Comparisons among these three subgroups with regards to cognitive performance and DTI parameters including fractional anisotropy (FA) and mean diffusivity (MD) values were performed. Partial correlation analysis after controlling for age and education was used to evaluate associations between cognitive performance and DTI parameters. Results With regards to cognitive performance, the patients with SIVD had lower total scores in frontal assessment battery (FAB) compared to those with AD (p < 0.05) in the context of comparable Mini-Mental Status Examination and Cognitive Abilities Screening Instrument scores. With regards to DTI parameters, there were more regions of significant differences in FA among these three subgroups compared with MD. Compared with NC group, the patients with SIVD had significant global reductions in FA (p < 0.001 ~ 0.05), while significant reductions in FA among the patients with AD were regionally confined within the left superior longitudinal fasciculus, genu and splenium of the corpus callosum, and bilateral forceps major, and the anterior thalamic radiation, uncinate fasciculus, and cingulum of the left side (p < 0.01 ~ 0.05). Analysis of FA values within the left forceps major, left anterior thalamic radiation, and genu of the corpus callosum revealed a 71.8% overall correct classification (p < 0.001) with sensitivity of 69.4%, specificity of 73.8%, positive predictive value of 69.4%, and negative predictive value of 73.8% in discriminating patients with SIVD from those with AD. In combined analysis of the patients with SIVD and AD (n = 75), the total FAB score was positively correlated with FA within the bilateral forceps minor, genu of the corpus callosum, left forceps major, left uncinate fasciculus, and right inferior longitudinal fasciculus (p = 0.001 ~ 0.038), and inversely correlated with MD within the right superior longitudinal fasciculus, genu and body of the corpus callosum, bilateral forceps minor, right uncinate fasciculus, and right inferior longitudinal fasciculus (p = 0.003 ~ 0.040) Conclusions Our findings suggest the effectiveness of DTI measurements in distinguishing patients with early-stage AD from those with SIVD, with discernible changes in spatial distribution and magnitude of significance of the DTI parameters. Strategic FA assessments provided the most robust discriminative power to differentiate SIVD from AD, and FAB may serve as an additional cognitive marker. We also identified the neuronal substrates responsible for FAB performance.

We analyze the announcement price behavior of independent director appointments stemming from monitoring, signaling, advising effects and moderating effects of controlling shareholders. Based upon appointments samples made by firms listed on the Taiwan Stock Exchange, we find that the cumulative abnormal returns (CARs) of the announcement of voluntary independent director appointments are significantly higher than those of the announcement of mandatory appointments. This empirical result indicates that the market may well recognize that voluntary appointments of independent directors could represent a signaling vehicle. Our findings also show that the monitoring and advising effects of independent directors has failed under the presence of controlling shareholders.

In 2002, the Taiwanese government regulated that new companies should appoint independent directors for good corporate governance. The purpose of this article is to compare appointing independent directors' motivation of structural changes in stock behaviour. The empirical results showed that the companies with mandatory or voluntary independent director appointments significantly reduced both stock returns and risks over 2000–2006.

Using data on listed companies in Taiwan from 1998 to 2009, our study investigates how controlling shareholder structure can affect debt maturity structure. The results indicate a significant negative relationship between ownership and debt maturity in the sample companies when control rights are lower than required control shareholdings. Conversely, the results also demonstrate that the separation of control from ownership displays a significant positive impact on debt maturity for controlling shareholder structure when control rights exceed cash-flow rights. Overall, our results show that there is an inverted U-shaped non-linear relationship between control rights and the duration of liabilities in the control structure of ultimate controlling shareholders. Further, the consequence is that we find the required control shareholdings ratio serves as an important criterion in analyzing it, when dividing the control rights structure based on controlling shareholders into different combinations.

We examine the value relevance of voluntary versus mandatory independent director appointments based on market reaction. Our analytical model proposes that the market expects voluntary appointments to bring more positive value than mandatory appointments since voluntary appointments signal the integrity of the firm, and this signaling effect is more obvious for firms in which the market recognizes the existence of severe agency problems. Using a unique empirical setting in Taiwan, we find that voluntary appointments are associated with higher abnormal returns from appointment announcements, particularly for firms with severe agency problems, as indicated by the deviation between ownership and control.

Pi-Calculus is a formal method for describing and analyzing the behavior of large distributed and concurrent systems. Pi-calculus offers a conceptual framework for describing and analyzing the concurrent systems whose configuration may change during the computation. With all the advantages that pi-calculus offers, it does not provide any methods for performance evaluation of the systems described by it; nevertheless performance is a crucial factor that needs to be considered in designing of a multi-process system. Currently, the available tools for pi-calculus are high level language tools that provide facilities for describing and analyzing systems but there is no practical tool on hand for pi-calculus based performance evaluation. In this paper, the performance evaluation is incorporated with pi-calculus by adding performance primitives and associating performance parameters with each action that takes place internally in a system. By using such parameters, the designers can benchmark multi-process systems and compare the performance of different architectures against one another.

In this paper, we propose a new failure-recovery model for workflow management systems (WfMSs). This model is supported with a new language, called the workflow failure-handling (WfFH) language, which allows the workflow designer to write programs so that he can use data-flow analysis technology to guide the failure recovery in workflow execution. With the WfFH language, the computation of the end compensation point and the compensation set for failure recovery can proceed during the workflow process run-time according to the execution results and status of workflow activities. Also, the failure-recovery definitions programmed with the WfFH language can be independent, thereby dramatically reducing the maintenance overhead of workflow processes. A prototype is built in a Java-based object-oriented workflow management system, called JOO-WfMS. We also report our experiences in constructing this prototype.

A three-phase voltage-source inverter for a power quality compensator under the unbalanced mains and nonlinear loads is proposed to provide balanced three-phase source current and improve input power factor. The proposed converter is based on the conventional three-phase voltage-source inverter with three additional ac power switches to achieve three-level pulsewidth modulation. The voltage stress of three ac power switches is clamped to half the dc-link voltage. The balanced reference mains currents are estimated using the dc-bus voltage and load currents. A proportional-integral voltage controller is used in the outer loop to compensate the switching losses of the voltage-source inverter. To perform the integrated power quality compensation, a hysteresis current control scheme is adopted to track the balanced line current command in phase with mains voltage. Three voltage levels are generated on the ac terminal of the proposed inverter. Computer simulation and experimental results are provided to verify the effectiveness of the proposed control scheme.

A three-phase four-wire power factor corrector based on neutral-point-clamped (NPC) topology is adopted to reduce the current harmonics and increase the input power factor. Using the NPC topology, the voltage stress of power switches can be reduced to the half of the dc-link voltage. With the dc-link voltage controller and the phase locked loop circuit, the balanced and sinusoidal line currents can be drawn from the ac supply system under the balance and unbalance mains voltages. The hysteresis current comparators are adopted in the current control loop to track the line current commands. Three voltage levels are generated on the ac terminal to the neutral point. Simulations and experiments are provided to verify the validity and the effectiveness of the proposed control scheme.

Without the security assurance from the underlining operating system, software agents and agencies are constantly under security threats through the operating system. Although the security issues between software agents and agencies have been studied intensively, any formulated counter-measurement of these issues are subject to attacks that are able to exploit the vulnerabilities of the operating system kernel (OS kernel). To protect agents and agencies against such risks, we proposed a novel approach that isolates the OS kernel and limit modifications to the agency system in the physical memory space. Our approach utilizes a hypervisor to create a virtualized environment for the operating system. The agency is then loaded into physical memory and injected into the operating system of the host without any interactions from the OS kernel. All memory access requests are monitored and managed by our approach to prevent unauthorized modification from the OS kernel and maintain the integrity of the agency system. Furthermore, any agent migrated to the host can be encrypted by our approach to prevent any alterations from the OS kernel. The encryption key is safely shared between the agency system and the hypervisor by utilizing part of the memory space of the agency as a communication interface. Consequently, our approach is able to limit the security threats that exploit the vulnerability of the operating system to the agency systems as well as ensure the integrity of both agents and agencies. This study describes the formulation and implementation of the proposed platform that can securely deploy agent agent systems to the host and effectively control access to host devices.

In this paper, we introduce an mobile agent framework with proactive load balancing for ambient intelligence (AmI) environments. One of the main obstacles of AmI is the scalability in which the openness of AmI environment introduces dynamic resource requirements on agencies. To mediate this scalability problem, our framework proposes a load balancing module to proactively analyze the resource consumption of network bandwidth and preferred agencies to suggest the optimal communication method to its user. The framework generally formulates an AmI environment that consists of three main components: (1) mobile devices, (2) hosts or agencies, and (3) directory service center (DSC). A preliminary implementation was conducted with NetLogo and the experimental results show that the proposed approach provides enhanced system performance by minimizing the network utilization to provide users with responsive services., {"references":["F. Bellifemine, G. Caire, T. Trucco, and G. Rimassa, \"Jade Programmer-s\nGuide,\" http://sharon.cselt.it/projects/jade/, 2002.","J. Borchers, M. Ringel, J. Tyler, and A. Fox, \"Stanford Interactive\nWorkspaces: A Framework for Physical and Graphical User Interface Prototyping,\"\nhttp://hci.stanford.edu/research/istuff/iRoom SmartHomes.pdf.","P. Braun and W. R. Rossak, Mobile Agents: Basic Concepts, Mobility\nModels, and the Tracy Toolkit. San Fransisco: Morgan Kaufmann, 2004.","S. Costantini, L. Mostarda, A. Tocchio, and P. Tsintza, \"DALICA:\nAgent- based ambient intelligence for cultural-heritage scenarios,\" IEEE\nIntelligent Systems, vol. 23, no. 2, pp. 3441, Mar. 2008.","Georgia Tech., \"Aware Home Research Initiative Residential\nLaboratory at Georgia Institute Of Technology,\"\nhttp://awarehome.imtc.gatech.edu/research.","Georgia Tech., \"eClass,\" http://www.cc.gatech.edu/fce/eclass/index.html.","H. Hagras, V. Callaghan, M. Colley, G. Clarke, A. Pounds-Cornish,\nand H. Duman, \"Creating an Ambient-Intelligence Environment Using\nEmbedded Agents,\" IEEE Intelligent Systems, Vol. 19, pp. 12-20, Nov.\n2004.","ISTAG,\"Scenarios for Ambient Intelligence in 2010,\"\nhttp://www.cordis.lu/istag.htm.","ISTAG, \"Ambient Intelligence: from vision to reality,\"\nhttp://www.cordis.lu/istag.htm.\n[10] C. Kidd, G. Abowd, C. Atkeson, I. Essa, B. MacIntyre, E. Mynatt,\nand T. Starner, \"The Aware Home: A Living Laboratory for Ubiquitous\nComputing Research,\" in the Proceedings of the Second International\nWorkshop on Cooperative Buildings, 1999, pp. 191-198.\n[11] Y. Lee, E. S.Khorasani, S. Rahimi, B. Gupta, \"A Generic Mobile Agent\nFramework for Ambient Intelligence,\" Proceedings of the 2008 ACM\nSymposium on Applied computing, 2008, pp. 1866-1871.\n[12] MIT, \"MIT Project Oxygen Pervasive Human-Centered Computing,\"\nhttp://www.oxygen.lcs.mit.edu/Overview.html.\n[13] PERSONA, http://www.aal-persona.org/.\n[14] Philips Research, \"Philips Research Technologies,\"\nhttp://www.research.philips.com/technologies/misc/homelab.\n[15] M. A. Perez, L. Susperregi, I. Maurtua, A. Ibarguren, F. Tekniker, and\nB. Sierra, \"Software Agents for Ambient Intelligence based Manufacturing,\"\nIEEE Workshop on Distributed Intelligent Systems: Collective\nIntelligence and Its Application, 2006.\n[16] I. Satoh, \"Software Agents for Ambient Intelligence,\" IEEE International\nConference on Systems man and Cybernetics, 2004.\n[17] SOPRANO, http://www.soprano-ip.org/.\n[18] U. Wilensky, \"Netlogo\". Center for Connected Learning\nand Computer-based Modelling, Northwestern University,\nhttp://ccl.northwestern.edu/netlogo.\n[19] Y. Zhang, Y. Hou, Z. Huang, H. Li, and R. Chen, \"A context-aware\nAmI system based on MAS model,\" IEEE Proceedings of the 2006 International\nConference on Intelligent Information Hiding and Multimedia\nSignal Processing, 2006, pp. 703-706."]}

The purpose of this paper is to introduce an innovative framework for implementation of ambient intelligence (AmI) environments. Compared to the existing state-of-the-art approaches, this framework creates a more decentralized and distributed AmI environment. In addition, the proposed approach is not limited to one specific domain, unlike many others. The openness of the presented architecture allows it to support a variety of devices ranged from small-embedded sensors to complex computing facilities. Finally, given that this approach is formulated based on multi-agent standard concepts, it can be easily implemented as add-on for existing software agent platforms to achieve rapid deployment. Implications for the development of this framework and future directions are discussed.

We propose a new approach towards particle swarm optimization named agent-based PSO. The swarm is elevated to the status of a multi-agent system by giving the particles more autonomy, an asynchronous execution, and superior learning capabilities. The problem space is modeled as an environment which forms clusters of points that are known to be non-optimal and this transforms the environment into a more dynamic and informative resource

An eight-switch three-phase neutral-point switch-clamped rectifier is presented to achieve the high input power factor and draw the sinusoidal currents from the AC mains. In the conventional three-phase neutral-point switch-clamped rectifier, the circuit configuration consists six power switches with voltage stress v/sub dc/ and three ac power switches with voltage stress V/sub dc//2. There are only four power switches with voltage stress of DC bus voltage and two AC power switches with a voltage stress of half the DC bus voltage in the proposed rectifier. The main functions of the proposed control scheme are to achieve unity input power factor, to draw the sinusoidal line currents from the AC source, and to keep the DC link voltage constant. The analysis and mathematical model of the proposed rectifier is derived. Some simulations and experimental results are provided to verify the effectiveness of the proposed control scheme.

This paper introduces a novel AC line conditioner with high input power factor and clean AC output voltages for isolating the linear or nonlinear loads. A four-wire AC/DC rectifier with switch-clamped topology is adopted to draw the balanced sinusoidal line currents from the AC supply system. The hysteresis comparators are used in the inner control loop to track the line current commands with unity power factor. The DC bus voltage controller is adopted in the outer control loop to regulate the DC-link voltage. A voltage compensator is used to reduce the voltage unbalance between the two DC side capacitor voltages. A four-wire three-leg inverter with switch-clamped topology is adopted in the system to provide clean AC output voltages to the critical or sensitive loads. The carrier-based current control scheme is adopted to generate the stable output voltages. There are three voltage levels generated on the phase to neutral voltage of the proposed system. Based on the proposed control scheme, the sinusoidal line currents with nearly unity power factor can be drawn from the AC supply system, and the balanced AC voltages can be provided to the output load. Experimental results show the validity and effectiveness of the proposed control strategy.

This paper presents a three-phase multilevel rectifier with reduced power switches to achieve high power factor, low harmonics and high voltage capability. In the conventional three-phase neutral point clamped rectifiers, twelve power switches are used to draw the sinusoidal line currents with unity power factor. The mains drawback of these systems is the large number of power switches used in the circuits. Only six power switches with voltage rating of half DC-link are adopted in the proposed multilevel rectifier. Based on the proposed control strategy, the input power factor is close to unity and line currents are controlled to be balanced and sinusoidal. Simulation results are provided to verify the effectiveness of the proposed control strategy.

A three-phase four-wire voltage source inverter for power quality compensator under the balanced and unbalanced conditions is proposed to provide balanced three-phase source currents and improve input power factor. The proposed inverter is based on the conventional three-phase voltage source inverter with three additional AC power switches to perform three-level pulse width modulation. The voltage stress of three AC power switches is clamped to half DC-link voltage. The balanced reference line currents are estimated using the DC bus voltage and load currents. A voltage controller is used in the outer loop control to compensate the switching losses of the voltage source inverter. To perform the integrated power quality compensation, hysteresis current control scheme is adopted to track the balanced line current commands in phase with mains voltages. Three voltage levels are generated on the AC terminal of the proposed inverter. Simulation results were provided to verify the effectiveness of the proposed control scheme.

A novel single-phase AC/AC converter with neutral-point diode-clamped scheme is proposed. Three-leg configuration which has a common leg between the AC/DC and DC/AC converters is adopted to reduce the number of switching devices compared with the conventional three-level AC/AC system. The common leg is operated in both rectifier and inverter modes. The rectifier is controlled to have a constant DC-link voltage and unity input power factor. The AC side of the rectifier has three-level PWM waveform to reduce the voltage harmonics compared with that of two-level scheme. The hysteresis current control scheme is used in the inner control loop to track the line current command. A proportional-integral (PI) control is adopted in the outer control loop to maintain the constant DC-link voltage. In the inverter side, a sinusoidal output voltage is generated to provide a stable and clean source voltage to the critical load. The fixed-frequency current controller is adopted to generate the properly PWM waveform. The output voltage is independent of the mains voltage to provide a stable AC power source. The neutral-point diode-clamped circuit configuration is used to reduce the voltage stress of power devices, The system model and control algorithm are described and analyzed. Simulation results were performed to verify the effectiveness of the proposed control strategies.

Covert channel attacks utilise shared resources to indirectly transmit sensitive information to unauthorised parties. Current operating systems (e.g. SELinux) rely on tagging the filesystem with security labels and enforcing security policies at the time of access to a file or resource. However, such mechanisms do not provide strong protection against information laundering via covert channels. Colored Linux, an extension to SELinux, utilises watermarking algorithms to ‘colour’ the contents of each file with their respective security classification, or context, to enhance resistance to information laundering attacks. In this study, the authors propose a mobile agent-based approach to automate the process of detecting and colouring receptive hosts' filesystems and monitoring the coloured filesystem for instances of potential information leakage. Implementation details and execution results are included to illustrate the merits of the proposed approach. The authors have also evaluated the performance of their agent-based system over a single host as well as a local network of machines. Finally, using formal method techniques, the authors have proved correctness properties about the agent-based approach and identified and corrected a flaw in their initial implementation.

A three-phase multilevel rectifier with reduced number of power switches to achieve high-power factor, low harmonics and high-voltage capability is presented. In the conventional three-phase neutral point clamped rectifier, 12 power switches are used to draw the sinusoidal line currents with unity power factor. The main drawback of these systems is the large number of power switches used in the circuits. Only six power switches with voltage rating of half DC-link are adopted in the proposed multilevel rectifier. Based on the proposed control strategy, the input power factor is close to unity and line currents are controlled to be balanced and sinusoidal. Simulation and experimental results are provided to verify the effectiveness of the proposed control strategy based on a laboratory prototype.

A new AC line conditioner with high input power factor and clean AC output voltages for isolating the linear or nonlinear loads is introduced. An AC/DC rectifier with switch-clamped topology is adopted to draw the balanced sinusoidal line current from the AC supply system. A three-leg inverter with switch-clamped topology is adopted in the system to provide clean AC output voltages to the critical or sensitive loads. Experimental results show the validity and effectiveness of the proposed control strategy.