19 results on '"Che-Min Lin"'
Search Results
2. Ethnic disparity in prevalence and associated risk factors of myopia in adolescents
- Author
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Che-Min Lin, Tzu-Heng Weng, Shih-Min Lin, and Shang-Yi Chiang
- Subjects
Male ,Adolescent ,National Health and Nutrition Examination Survey ,Population ,Ethnic group ,Lower risk ,White People ,Odds ,Risk Factors ,Mexican Americans ,Myopia ,Prevalence ,Humans ,Medicine ,Risk factor ,education ,lcsh:R5-920 ,education.field_of_study ,business.industry ,Hispanic or Latino ,General Medicine ,Odds ratio ,Nutrition Surveys ,United States ,Confidence interval ,Black or African American ,Logistic Models ,Socioeconomic Factors ,Multivariate Analysis ,Female ,lcsh:Medicine (General) ,business ,Demography - Abstract
Background/Purpose: To examine ethnic disparity in prevalence and associated factors of myopia in adolescents using the Unites States National Health and Nutrition Examination Survey (NHANES) dataset. Methods: Participants who were aged 12–19 years were included from NHANES (1999–2008). Logistic regression analyses were applied to identify risk factors associated with myopia after stratification by race. Results: A total of 9,960 participants were included in the prevalence analysis, and 6,571 in the risk factor analysis. Other race (excluded Mexican American, other Hispanic, non-Hispanic white, non-Hispanic black) participants had the highest frequency of myopia (42.77%). Multivariate analyses of the whole population suggested that the odds of myopia were significantly lower in participants with household smokers (odds ratio [OR] = 0.79, 95% confidence interval [CI]: 0.66–0.97), and significantly greater in Mexican American race (OR = 1.28, 95% CI: 1.01–1.62), other Hispanic (OR = 1.79, 95% CI: 1.10–2.92) and in participants with senior high school graduate education (OR = 1.79, 95% CI: 1.01–3.18), watched 2 hours of television daily (OR = 1.27, 95% CI: 1.02–1.59), used the computer for 1 hour daily (OR = 1.276, 95% CI: 1.02–1.57). When examined by race/ethnicity, 1 hour of computer use increased the odds of myopia in the non-Hispanic White group, in Mexican Americans a higher family poverty income ratio and 2 hours of television time was associated with myopia, and in the Other Hispanic group, a higher family poverty income ratio was associated with myopia, while males and those with a higher sugar had a lower risk of myopia. Conclusion: Risk factors for myopia vary with race/ethnicity. Keywords: Adolescent, Myopia, Racial disparity, Risk factor, NHANES
- Published
- 2020
3. Standby Power Management of a Smart Home Appliance by Using Energy Saving System With Active Loading Feature Identification
- Author
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Che-Min Lin and Ming-Tang Chen
- Subjects
business.industry ,Computer science ,020206 networking & telecommunications ,02 engineering and technology ,Energy consumption ,Reliability engineering ,Energy conservation ,Electric energy ,Identification (information) ,Home automation ,0202 electrical engineering, electronic engineering, information engineering ,Media Technology ,Electrical and Electronic Engineering ,business ,Standby power ,Energy (signal processing) - Abstract
Recently, energy conservation has been concerned, and there are several aspects to improve the energy consumption issues. Therefore, many research results were proposed to mitigate the related problems, one of these is to eliminate the extra standby power of household appliances. This paper employed an effective method to identify load characteristics of appliances in different operation states by support vector machines, and a smart home electric energy saving system was built up to implement the method. Furthermore, a virtual living room was simulated in the laboratory as an experimental object, and a prototype system was built up. The performance test results are proposed to validate the feasibility of the proposed system.
- Published
- 2019
4. Electrically tunable bandgaps for g-ZnO/ZnX (X = S, Se, Te) 2D semiconductor bilayers
- Author
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Li-Wei Tu, Yu-Hsuan Yu, Chun-Fu Chang, Chi-Chung Kei, Tsan-Chuen Leung, Chien-Wei Chen, Yu-yuan Zheng, Hye-Won Seo, Sung-Wei Yeh, Bor Yann Liaw, Kuan-Tsae Huang, Wanchen Hsieh, P.V. Wadekar, Quark Y. Chen, Kung-Shiuh Huang, Chun-Jung Su, Che-Min Lin, Wei-Kan Chu, Di Chen, Ching-Wen Chang, Yu-Chiao Lin, and Chih-Hsiung Liao
- Subjects
010302 applied physics ,Materials science ,Condensed matter physics ,Condensed Matter::Other ,business.industry ,Orbital hybridisation ,Band gap ,Stacking ,Heterojunction ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Surfaces, Coatings and Films ,Condensed Matter::Materials Science ,Dipole ,Semiconductor ,0103 physical sciences ,Quadrupole ,0210 nano-technology ,Valence electron ,business ,Instrumentation - Abstract
Novel physical properties not seen in their individual layers are obtained from stacked layers of materials. In this report, using the first-principles calculations, we study the electronic band structures of heterostructures composed of graphitic (graphene-like) bilayers of g-ZnO/ZnX (X = S, Se, and Te) semiconductors. The g-ZnO layer is largely planar, but the ZnX layer is somewhat corrugated. Our calculations reveal on the stable formations of a type-II band alignment in bilayers with an AB stacking order of OZnO-ZnZnX and ZnZnO-XZnX. The optical bandgaps are much lowered as compared to the monolayers of ZnO and ZnX constituents, with the conduction band contributed by g-ZnO and valence band by ZnX. There is a quadratic dependence of the bandgap on the external electric biases applied in perpendicular to the interface. This nonlinearity manifests an superposed effect of an interlayer orbital hybridization and associated charge transferring, along with the coexistence of an electric dipole and a quadrupole. There is an overall charge transfer of valence electrons from the ZnX layer to the g-ZnO layer, leading to a pair of highly charge polarized surfaces along with a large built-in potential. The already lowered bandgaps further change with the external bias. This tunability of Eg for g-ZnO/ZnX bilayer heterostructures holds promises for optoelectronic applications covering a wider spectral range of the solar spectrum.
- Published
- 2021
5. Characteristics of Optic Disc and Visual Field Changes in Patients with Thyroid-Associated Orbitopathy and Open-Angle Glaucoma
- Author
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Ke-Hung Chien, Chih-Kang Hsu, Yi-Hao Chen, Da-Wen Lu, Hsin-Yu Yao, Hsu-Chieh Chang, and Che-Min Lin
- Subjects
medicine.medical_specialty ,genetic structures ,Open angle glaucoma ,Nerve fiber layer ,open-angle glaucoma ,Glaucoma ,Article ,Optical coherence tomography ,Ophthalmology ,medicine ,hyperthyroidism ,medicine.diagnostic_test ,business.industry ,Blind spot ,Thyroid ,thyroid eye disease ,General Medicine ,medicine.disease ,eye diseases ,Visual field ,medicine.anatomical_structure ,thyroid-associated orbitopathy ,Medicine ,sense organs ,business ,Optic disc - Abstract
This study aimed to characterize the changes in the visual field (VF) patterns and disc morphology of patients with thyroid-associated orbitopathy (TAO) and open-angle glaucoma (OAG). A retrospective review of the medical records at the Tri-Service General Hospital in Taiwan identified 396 eyes of 198 patients with thyroid-associated glaucoma. A final follow-up of VF examination in 140 eyes revealed 114 eyes with VF defects, indicating disease progression. The characteristics of and changes in disc morphology, optical coherence tomography findings, and VF defects were statistically analyzed. The most common VF defects at the initial diagnosis and the end of the follow-up period were inferior partial arcuate (17%) and paracentral (15%) defects, respectively. The most common VF defect in patients with unspecific disc signs was an unspecific scotoma (13%). The most common optic disc feature was disc cupping (51%), followed by parapapillary atrophy (48%). The most frequent location of nerve fiber layer thinning was the inferotemporal region (48%). VF defects showed a significantly more pronounced progression in the non-nerve fiber bundle group than in the nerve fiber bundle group (p <, 0.001). This study details the characteristics and progression of disc morphology and VF defects in patients with TAO and OAG.
- Published
- 2021
6. Masseter Muscle Volume Changes Evaluated by 3-Dimensional Computed Tomography After Repeated Botulinum Toxin A Injections in Patients With Square Facial Morphology
- Author
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Philip Kuo Ting Chen, Jyh-Ping Chen, Che Min Lin, Christopher Glenn Wallace, Chun Shin Chang, Susie Lin, Lun-Jou Lo, Zung Chung Chen, Yen Chang Hsiao, Yu Ray Chen, and Gavin Chun-Wui Kang
- Subjects
Adult ,Esthetics ,3 dimensional computed tomography ,030230 surgery ,Injections, Intralesional ,Injections, Intramuscular ,Sampling Studies ,Statistics, Nonparametric ,Botulinum toxin a ,Masseter muscle ,03 medical and health sciences ,0302 clinical medicine ,Imaging, Three-Dimensional ,Medicine ,Neurotoxin ,Humans ,In patient ,Botulinum Toxins, Type A ,Contouring ,business.industry ,Masseter Muscle ,Hypertrophy ,Organ Size ,Middle Aged ,Treatment Outcome ,030220 oncology & carcinogenesis ,Surgery ,Female ,Tomography ,business ,Nuclear medicine ,Tomography, X-Ray Computed ,Volume (compression) - Abstract
Botulinum neurotoxin A (BoNT-A) is a minimally invasive and technically straightforward treatment of masseter muscle (MM) volume reduction and facial contouring, but the literature on its long-term effect on MM volume remains unclear.This study aimed to assess quantitatively for progressive volume changes of lower facial contour after 3 BoNT-A injections in patients with bilateral MM hypertrophy causing square facial morphology using 3-dimensional computed tomographic scans.Ten female patients with square facial morphology due to bilateral MM hypertrophy were recruited to, and 6 completed, this clinical study. Each received 24 U of BoNT-A into the inferior portion of each MM on both sides, repeated 6 monthly to complete 3 treatments. Masseter muscle volume changes were assessed using 3-dimensional computed tomography at pretreatment (before injections) and posttreatment (1 year after the third injection).Mean MM volume significantly reduced from 26.39 ± 4.18 cm before treatment to 23.26 ± 4.31 cm 1 year after treatment (P = 0.002).Three consecutive 6-monthly BoNT-A injections into the MMs reduced their volume by 12% when assessed 1 year after completion of treatment.
- Published
- 2018
7. Development of a smart home energy saving system combining multiple smart devices
- Author
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Ming-Tang Chen and Che-Min Lin
- Subjects
Engineering ,Smart system ,business.industry ,Smart meter ,Control unit ,020206 networking & telecommunications ,SDS Protocol ,02 engineering and technology ,Power (physics) ,Home automation ,Power consumption ,Embedded system ,0202 electrical engineering, electronic engineering, information engineering ,business ,Energy (signal processing) - Abstract
In this paper, a smart home electric energy saving system is built up by combining smart devices (smart meter and smart plug), communication modules, and smart mobile phones. The functions of the smart meter include display and storage of total power consumption, electric energy parameters, and abnormal operation conditions, etc. Besides, user can check power consumption information remotely, and the electric energy saving of appliance is implemented by smart plug under the control of smart phone. The smart plug consists of different communication modules, load control unit, and LCD display. Home members can use smart phone to check the power consuming information via internetwork, and the control of electric appliance can be implemented by the App on the smart phone through the WiFi interfaces. Moreover, the power information at the smart plug can be transmitted to the smart meter by ZigBee modules. Finally, to confirm the performance of the smart home electric energy saving system, a prototype was built up and tested at lab, and the test results validate the feasibility of the proposed system.
- Published
- 2016
8. Site classification and Vs30 estimation of free-field TSMIP stations using the logging data of EGDT
- Author
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Kai Wen Kuo, Kuo-Liang Wen, Tao Ming Chang, Che Min Lin, Hung Hao Hsieh, and Chun Hsiang Kuo
- Subjects
Estimation ,Engineering ,Earthquake engineering ,business.industry ,Instrumentation ,Logging ,Borehole ,Extrapolation ,Geology ,Geotechnical Engineering and Engineering Geology ,Geodesy ,Free field ,Set (abstract data type) ,Geotechnical engineering ,business - Abstract
The Engineering Geological Database for TSMIP (EGDT), the Taiwan Strong Motion Instrumentation Program, has been under construction by the National Center for Research on Earthquake Engineering and the Central Weather Bureau in Taiwan since 2000. Site characterization, comprising surface investigations and logging measurements, was carried out throughout the project. We provide a set of specifications and a description to help users understand the subject matter of the database. EGDT contains 469 surveyed stations, 439 of which were drilled and the logging measurements completed. Of these, 385 had logging data reaching at least 30 m, and we used these to examine and determine the most accurate extrapolation of Vs30 (the average S-wave velocity of the top 30 m of strata) for the other 54 stations with velocity profiles less than 30 m. The chosen method assumed that the bottom velocity is identical from the actual depth of the hole to a distance of 30 m, that is, the Bottom Constant Velocity (BCV) method. In order to utilize other existing boreholes which have only N values but no velocities in the future, the empirical S-wave velocity equations for seven different regions and the whole of Taiwan were evaluated by a multivariable analysis. Henceforth, for those existing boreholes which have an N profile less than 30 m, the S-wave velocity profile can first be calculated by empirical S-wave velocity equations, and then Vs30 can be estimated by reliable extrapolation. Some other studies of site classifications of TSMIP stations were compared with our results to demonstrate the necessity of reclassification. Ultimately, the Vs30 values of the 439 drilled free-field TSMIP stations were derived and the new site classification was achieved according to the Vs30-based provisions of the National Earthquake Hazards Reduction Program.
- Published
- 2012
9. A Self-Sensing Microgripper Module With Wide Handling Ranges
- Author
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Che-Min Lin, Chao-Chieh Lan, and Chen-Hsien Fan
- Subjects
Engineering ,business.industry ,technology, industry, and agriculture ,Mechanical engineering ,Stiffness ,Shape-memory alloy ,Structural engineering ,SMA ,Computer Science Applications ,body regions ,Control and Systems Engineering ,Grippers ,medicine ,Mechanical advantage ,Electronics ,Electrical and Electronic Engineering ,medicine.symptom ,business ,Robotic arm ,Contraction (operator theory) - Abstract
A compliant two-fingered microgripper is designed, fabricated, and demonstrated. To mimic human finger actuation, the proposed finger is distributively actuated by a shape memory alloy (SMA) wire. An SMA-actuated finger model is presented to predict SMA strain and finger motion given its contraction force. Based on this model, the finger shape and SMA wire dimension are optimally designed. The gripper is shown to have a wide handling range, high mechanical advantage, and sufficient out-of-plane stiffness; thus, it can accommodate objects of various sizes and weights. To control its motion, the SMA contraction force is estimated by using the proposed force to electrical resistance model. Gained from the simple driving electronics and self-sensing of SMA, the fabricated gripper can be made compact and lightweight. Finally, a self-powered gripper module is attached to a robot arm to perform several illustrative manipulations.
- Published
- 2011
10. Machine Learning-Based Configuration Parameter Tuning on Hadoop System
- Author
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Chao-Chun Yeh, Ye-Qi Zhuo, Shih-Wei Liao, Che-Min Lin, and Chi-Ou Chen
- Subjects
Optimization problem ,Computer science ,business.industry ,Process (computing) ,Machine learning ,computer.software_genre ,Software framework ,Task (computing) ,Job performance ,Programming paradigm ,Key (cryptography) ,Artificial intelligence ,Focus (optics) ,business ,computer - Abstract
Apache Hadoop system is a software framework with the capability to process large-scale datasets across a cluster of distributed machines using MapReduce programming model. However, there are two main challenges for system administrators to manage the Hadoop system, (1) system administrators are difficult to tune the parameters appropriately since the behaviors and characteristics of large-scale distributed systems are too complicated, (2) there are dozens of configuration parameters affecting the system performance which makes the configuration parameters tuning task becomes troublesome. In this paper, we focus on optimizing the Hadoop MapReduce job performance by tuning configuration parameters, and then we propose an analytical method to help system administrators choose approximately optimal configuration parameters depending on the characteristics of each application. Our approach has two key phases: prediction and optimization phase. The prediction phase is to estimate the performance of a MapReduce job, whereas the optimization phase is to search the approximately optimal configuration parameters strategically by invoking the predictor repeatedly. In our evaluation results, our work can help system administrators to improve the performance about 2X to 8X better than traditional methods.
- Published
- 2015
11. Design and implementation of a smart home energy saving system by multi-microprocessors
- Author
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Ming-Tang Chen and Che-Min Lin
- Subjects
Power-line communication ,Engineering ,Smart grid ,Electricity meter ,Smart meter ,business.industry ,Energy management ,Embedded system ,Electric energy consumption ,Electric power ,Standby power ,business - Abstract
This paper proposes a home electric energy saving network which consists of a smart meter and a smart plug. The smart meter can not only measure electric power parameters of a load also identify the operation status of a device which is connected to the smart plug. Therefore, the standby power consumption of the device can be reduced to the minimum through the electric energy management algorithm. Besides, real time electric energy consumption and standby power information will be delivered to the assigned user through the communication network of the smart meter; so, the reliability and the effectiveness of home electric energy management can be improved. For the hardware structure, the system includes digital signal processors (DSPs), a power energy IC, a smart plug and a communication module. Regarding software development, the system has the following functions: energy recording, standby power consumption management, electric billing, and power information collection. The system prototype is installed at a personal residence, and the performance is validated by the test results.
- Published
- 2015
12. A case report of Löfgren's syndrome (a variant of sarcoidosis) with atypical manifestations in a Taiwan Chinese man
- Author
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Chia-Hung Li, Ming-Ling Tsai, Chi-Ting Horng, Da-Wen Lu, Che-Min Lin, and Chun-Ling Hung
- Subjects
medicine.medical_specialty ,S syndrome ,Conjunctiva ,Löfgren's syndrome ,Atypical manifestations ,medicine.diagnostic_test ,Systemic steroid ,business.industry ,medicine.disease ,Dermatology ,Dysphagia ,eye diseases ,Surgery ,Ophthalmology ,acute body weight loss ,medicine.anatomical_structure ,Hilar lymph nodes ,ocular redness ,Biopsy ,medicine ,sarcoidosis ,sense organs ,Sarcoidosis ,medicine.symptom ,business - Abstract
A 28-year-old Chinese man presented with refractory ocular redness in the bilateral eyes. His symptoms co-existed with dysphasia and acute body weight loss. Excisional biopsy of the conjunctiva and hilar lymph nodes was performed and Lofgren's syndrome was confirmed. The patient was treated with systemic steroid and symptoms gradually subsided over the 2-year follow-up period. Ocular redness and dysphagia with acute body weight loss are atypical symptoms of Lofgren's syndrome. Careful survey and prompt treatment is necessary.
- Published
- 2012
13. A Study on the Integration of ISO 27001 & 27011 and the New Personal Information Protection Act in the Telecom Enterprises in Taiwan
- Author
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Che-Min Lin, I-Long Lin, and Che-Jui Sun
- Subjects
business.industry ,Computer science ,Mobile broadband ,Information security ,computer.software_genre ,Security information and event management ,Information security management ,Personal information manager ,Personal information management ,Telecommunications ,business ,computer ,Personally identifiable information ,Information security management system - Abstract
Due to the flourishing development of mobile communications, Internet businesses, and mobile broadband, handheld mobile communications equipment is commonplace and the number of mobile phone users and fixed-line broadband users is growing rapidly every day. As the telecom industry stores massive amounts of users' personal Information, operators need to uphold users' trust in them, so users can enjoy the telecommunication services worry-free! Personal information security is of major concern in society today and also a social responsibility of enterprises. In response to the new Personal Information Protection Act in Taiwan, how carriers with imported information security management system can integrate the new Personal Information Protection Act to achieve their custodial responsibility must be discussed. Through the key management elements of ISO27001 & ISO27011 that correspond to the norms set to the appropriate security maintenance measures in Article 12 of the new Personal Information Protection Act Enforcement Rules in Taiwan, how carriers can strengthen management and educational training in compliance with the Act also requires discussion in Taiwan.
- Published
- 2013
14. A 0.27mm2 13.5dBm 2.4GHz all-digital polar transmitter using 34%-efficiency Class-D DPA in 40nm CMOS
- Author
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Yi-Hsien Cho, Paul Cheng-Po Liang, Meng-Hsiung Hung, Jie-Wei Lai, Xin-Yu Shih, Lan-Chou Cho, Yuan-Hung Chung, Chi-Hsueh Wang, Hung-Sung Li, Sheng-Hong Yan, Kaipon Kao, Robert Bogdan Staszewski, Guang-Kaai Dehng, George Chien, Anson Lin, and Che-Min Lin
- Subjects
Engineering ,business.industry ,Transmitter ,Electrical engineering ,Reconfigurability ,Polar transmitter ,Power (physics) ,law.invention ,Bluetooth ,CMOS ,law ,Electronic engineering ,System on a chip ,business ,Electrical efficiency - Abstract
An all-digital polar transmit (TX) architecture exhibits advantages of low cost, low power, as well as reconfigurability with full usage of digital computational power. The design challenge is the need for continuous innovation to further enhance power efficiency and minimize silicon area while achieving the best-in-class RF performance. The design must also meet the increasing demand of concurrent operation for multi-radio SoC integration. The presented Bluetooth TX demonstrates advancements in this direction with over 30% power and 66% area reduction.
- Published
- 2013
15. Implementation of a internet-based power quality monitoring system by dual microprocessors
- Author
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Sheng-Jen Hsiao, Che-Min Lin, Ming-Tang Chen, Chen-Wen Lu, and Cong-Jun Han
- Subjects
Database server ,Upload ,Digital signal processor ,Engineering ,business.industry ,Server ,Embedded system ,Computer data storage ,Condition monitoring ,The Internet ,business ,Raw data ,Computer hardware - Abstract
In this paper two low-cost microprocessors are employed to build up a internet-based instrument system for remote monitoring of power quality, the instrument system can collect various types of power quality disturbances in interactive or automatic mode. Besides, an SD data storage device is used to save raw data which can be also uploaded to a database server via internet, users can access the server by an ordinary browser to effectively realize the information of power quality conditions at a certain location. The built-up prototype of the system is tested in different ways, and the test results validate the performance and feasibility of the instrument system.
- Published
- 2011
16. Fungal endophthalmitis caused by Trichophyton spp. after cataract surgery
- Author
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Ching-Long Chen, Da-Wen Lu, Shu-I Pao, Jiann-Torng Chen, Che-Min Lin, and Yi-Hao Chen
- Subjects
medicine.medical_specialty ,Visual acuity ,biology ,business.industry ,medicine.medical_treatment ,After cataract ,Phacoemulsification ,Fungal endophthalmitis ,Eye infection ,biology.organism_classification ,Surgery ,Ophthalmology ,Pharmacotherapy ,medicine ,Trichophyton ,medicine.symptom ,business - Published
- 2014
17. A shape memory alloy actuated microgripper with wide handling ranges
- Author
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Chen-Hsien Fan, Chao-Chieh Lan, and Che-Min Lin
- Subjects
Engineering ,business.industry ,Capacitive sensing ,Stiffness ,Shape-memory alloy ,Structural engineering ,SMA ,Force sensor ,Grippers ,Deflection (engineering) ,medicine ,Mechanical advantage ,medicine.symptom ,business - Abstract
A compliant two-fingered microgripper was designed, fabricated, and demonstrated. To accommodate objects of various sizes and weights, the gripper is distributively actuated by shape memory alloy (SMA) wires so that high gripping range to gripper length ratio and mechanical advantage are achieved. A SMA actuated gripper model is presented to predict SMA strain and gripper deflection by using measurements from force sensors. Based on this model, design of finger shape and specification of SMA wire dimension are facilitated. Two grippers with different stiffness are prototyped and their motion characteristics demonstrated. Due to the large stress provided by SMA wires, high gripping force can be obtained. The SMA contraction force to deflect gripper and produce gripping force may be adjusted by changing the input power to SMA wire. We further investigate the feasibility of self-sensing contraction force by using SMA resistance signal. With the capabilities of the gripper shown, we expect that it can be applied for miniature robotic manipulations.
- Published
- 2009
18. Bandwidth Efficient Video Streaming Based Upon Multipath SVC Multicasting
- Author
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Chun-Kai Yang, Che-Min Lin, John K. Zao, Hsin-Min Chen, Chia-Chi Hu, and Wen-Hsiao Peng
- Subjects
Lossless compression ,Multicast ,Computer science ,business.industry ,Real-time computing ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Data_CODINGANDINFORMATIONTHEORY ,Lossy compression ,Scalable Video Coding ,Broadcasting (networking) ,Distortion ,Bit rate ,Bandwidth (computing) ,business ,Decoding methods ,Multipath propagation ,Computer network - Abstract
The scalable video coding (SVC) extension of H.264/AVC was designed to support bandwidth efficient and loss resilient video streaming. Its multilayer predictive encoding enables user devices to adapt their video reception by extracting and decoding selected code layers according to device display capability and network throughput. However, this desirable feature is much harder to realize in practice as the reduction of coding efficiency causes inflation of SVC bitstreams. Consequently, an SVC multicast session among clusters of heterogeneous devices may consume more bandwidth than an AVC simulcasting session. In this paper, we propose a bandwidth efficient scheme for conducting heterogeneous SVC multicasting. The proposed scheme employs a combination of three transport techniques: (1) broadcasting of SVC layers in local service subnets, (2) multipath transport of SVC layers over long- haul networks and (3) aggregation of data flows along transport paths. This scheme is particularly suited for delivering SVC bitstreams to different user devices scattered over geographically dispersed local subnets. Preliminary simulation experiments performed over lossless networks showed that the scheme can introduce from 2:1 to 6:1 reduction of up-stream bandwidth for SVC layer transport. It can also maintain 85% transport efficiency while minimizes PSNR loss of most user devices even under heavy traffic. We expect the proposed scheme will achieve better rate- distortion performance than AVC simulcasting over lossy networks if unequal erasure protection (UEP) will be applied to the lower SVC layers. Further investigation of its potential is currently underway.
- Published
- 2008
19. Trickle: Resilient Real-Time Video Multicasting for Dynamic Peers with Limited or Asymmetric Network Connectivity
- Author
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Che-Min Lin, Wen-Hsiao Peng, Lin-Shung Huang, Fang-po Kuo, John K. Zao, and Yu-hsuang Guo
- Subjects
Multicast ,business.industry ,Computer science ,Distributed computing ,Frame (networking) ,IPTV ,Throughput ,computer.file_format ,Application layer ,Telecommunications link ,Wireless ,business ,BitTorrent ,computer ,Computer network - Abstract
some of the most challenging scenarios for peer-to-peer multimedia applications arise when the applications require real-time interactions among their users. In those cases, the expectation of sub-second responses prohibits the use of popular P2P IPTV software because those programs invariably use large video buffers to amortize the propagation delays of individual frames and thus cause notable and dispersed viewing latencies among their users. The performance of these programs degrade even further if the users are connected to home networks that offer narrow uplink channels or through wireless links that experience frequent throughput fluctuations. In order to overcome these shortcomings, we develop Trickle, a peer-to-peer real-time media streaming system that can transport H.264 video streams with low link stresses (less than 250Kb/s) and stable sub-second frame delays through the use of erasure correction codes along with the clever construction of multiple multicast trees and the recruitment of many peer helpers. This paper presents the first fruits of our work including the principles and mechanisms of Trickle, its simulated performance based on H.264 video traces and its merit comparisons against SplitStream, the first application layer multicasting protocol for video streaming, and CoolStreaming, a news-making P2P IPTV program that works like BitTorrent.
- Published
- 2006
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