• Title/Summary/Keyword: self-operated

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Self Organization of Sensor Networks for Energy-Efficient Border Coverage

  • Watfa, Mohamed K.;Commuri, Sesh
    • Journal of Communications and Networks
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    • v.11 no.1
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    • pp.57-71
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    • 2009
  • Networking together hundreds or thousands of cheap sensor nodes allows users to accurately monitor a remote environment by intelligently combining the data from the individual nodes. As sensor nodes are typically battery operated, it is important to efficiently use the limited energy of the nodes to extend the lifetime of the wireless sensor network (WSN). One of the fundamental issues in WSNs is the coverage problem. In this paper, the border coverage problem in WSNs is rigorously analyzed. Most existing results related to the coverage problem in wireless sensor networks focused on planar networks; however, three dimensional (3D) modeling of the sensor network would reflect more accurately real-life situations. Unlike previous works in this area, we provide distributed algorithms that allow the selection and activation of an optimal border cover for both 2D and 3D regions of interest. We also provide self-healing algorithms as an optimization to our border coverage algorithms which allow the sensor network to adaptively reconfigure and repair itself in order to improve its own performance. Border coverage is crucial for optimizing sensor placement for intrusion detection and a number of other practical applications.

A Concept Study on Efficient Domestic Development of 120mm Self-propelled Mortar System (120mm 자주박격포의 효율적인 국내 연구개발 개념)

  • Kim, Seok;Kim, Ki-Hoon;Kim, Seong-Young
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.2
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    • pp.133-138
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    • 2009
  • A mortar system is able to be fired more rapidly and concentratedly than other field gun systems. A mortar system can be easily manufactured because of its simple structure. It has also been supporting for the fire power of infantry because it can be carried conveniently. But a mortar system has demerits that are the limited firing range, poor accuracy and uncomfortable operability. Korean army plan to be operated rapidly and enlarge battle field in the near future. So weapon systems of Korean army must have longer firing range, automatic laying function and precision firing capability. This study suggests efficient developing concept of 120mm self-propelled mortar system through surveying the technical readiness level of current R&D and manufacturing ability.

A Study on Problem-based Learning Model of Orthopedic Manual Physical Therapy (정형도수물리치료의 문제중심학습 모형에 관한 고찰)

  • Kim, Ho-Bong;Bang, Sang-Bun
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.18 no.2
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    • pp.31-39
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    • 2012
  • Background: The purpose of this study was to develop a problem-based learning model for orthopedic manual physical therapy. A problem-based learning (PBL) model for orthopedic manual physical therapy developed from PBL module of Jeju C university (Halla-Newcastle PBL Center). A summary of this study is as follows: 1) PBL model is comprised of a class of 30 students, operated small group as of 4~5 students. 2) PBL is suggested a scenario of clinical case, induced variety reaction through group discussion and presentation. 3) PBL is occurred wide variety learning through group work activity and self-directed learning. 4) The tutor as a facilitator is played a guide for group discussion, work activity and team learning. 5) The evaluation for PBL is performed such as student self-evaluation, group activity evaluation, individual presentation, and practice. This model is considered wide variety learning through team learning and self-directed learning by clinical reasoning and problem solving for musculoskeletal clinical case. We suggest problem based learning for the education of orthopedic manual physical therapy in which the learners are very interested in and has the effective outcome.

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Fabrication of All-Nb Josephson Junction Array Using the Self-Aligning and Reactive ion Etching Technique (Self-Aligning 기술과 반응성 이온 식각 기술로 제작된 Nb 조셉슨 접합 어레이의 특성)

  • Hong, Hyun-Kwon;Kim, Kyu-Tea;Park, Se-Il;Lee, Kie-Young
    • Progress in Superconductivity
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    • v.3 no.1
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    • pp.49-55
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    • 2001
  • Josephson junction arrays were fabricated by DC magnetron sputtering, self-aligning and reactive ion etching technique. The Al native oxide, formed by thermal oxidation, was used as the tunneling barrier of Nb/$Al-A1_2$$O_3$Nb trilayer. The arrays have 2,000 Josephson junctions with the area of $14\mu\textrm{m}$ $\times$ $46\mu\textrm{m}$. The gap voltages were in the range of 2.5 ~2.6 mV and the spread of critical current was $\pm$11~14%. When operated at 70~94 ㎓, the arrays generated zero-crossing steps up to 2.1~2.4 V. To improve transmission of microwave power and prevent diffusion of oxygen into Nb ground-plane while depositing $SiO_2$dielectric, we applied a plasma nitridation process to the Nb ground-plane. The microwave power was well propagated in Josephson junction arrays with nitridation. The difference in microwave transmission 7an be interpreted by the surface impedance change depending on nitridation.

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산화아연 압전 나노전력발전소자 기반 에너지 하베스팅

  • Kim, Sang-U
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.49-49
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    • 2010
  • Nanopiezotronics is an emerging area of nanotechnology with a variety of applications that include piezoelectric field-effect transistors and diodes, self-powered nanogenerators and biosystems, and wireless nano/biosensors. By exploiting coupled piezoelectric and semiconducting characteristics, it is possible for nanowires, nanobelts, or nanorods to generate rectifying current and potential under external mechanical energies such as body movement (handling, winding, pushing, and bending) and muscle stretching, vibrations (acoustic and ultrasonic waves), and hydraulic forces (body fluid and blood flow). Fully transparent, flexible (TF) nanogenerators that are operated by external mechanical forces will be presented. By controlling the density of the seed layer for ZnO nanorod growth, transparent ZnO nanorod arrays were grown on ITO/PES films, and a TF conductive electrode was stacked on the ZnO nanorods. The resulting integrated TF nanodevice (having transparency exceeding 70 %) generated a noticeable current when it was pushed by application of an external load. The output current density was clearly dependent on the force applied. Furthermore, the output current density depended strongly on the morphology and the work function of the top electrode. ZnO nanorod-based nanogenerators with a PdAu, ITO, CNT, and graphene top electrodes gave output current densities of approximately $1-10\;uA/cm^2$ at a load of 0.9 kgf. Our results suggest that our TF nanogenerators are suitable for self-powered TF device applications such as flexible self-powered touch sensors, wearable artificial skins, fully rollable display mobile devices, and battery supplements for wearable cellular phones.

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Fabrication and charateristics of the foot-spa driving circuit using ultrasonic vibrator (초음파 진동자를 이용한 족욕기용 구동회로 제작 및 특성)

  • Jang, Eun-Sung;Kim, Hyeung-Kyu;Lee, Sang-Ho;Yoo, Ju-Hyun;Hwang, Lak-Hoon;Jeong, Hoy-Seung;Chung, Kwang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.705-709
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    • 2004
  • In this study, the foot-spa driving circuit using ultrasonic vibrator was manufactured The used ultrasonic vibrator was PSN-PMN-PZT ceramic with the radius of $25{\Phi}$ and the thickness of 2, 2.5, 3, 3.5 and 4mm, respectively. Resonent frequency for driving ultrasonic vibrator at the fabricated circuit was generated using the self exciting and the external exciting methods. Fabricated foot-spa showed the best condition at the resonent frequency of 1.130MHz and the ceramic thickness of 2.0mm. That is, when the foot-spa was operated for 360 min. at $0.5\ell$ water, temperature increase of water was $14^{\circ}C$ at the self exciting method and $16^{\circ}C$ at the external exciting methods, respectively.

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A Study on the Relationship between the Breast Self-Examination and the severity of breast cancer (유방암 자가검진 유무와 질병의 중증도와의 관계연구)

  • Lee, Yun-Jung;Uhm, Dong-Choon
    • The Korean Journal of Rehabilitation Nursing
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    • v.2 no.2
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    • pp.225-233
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    • 1999
  • The purpose of this study is to determine the need of education about BSE for the medical members, to survey about the performance and the knowledge of BSE in patients who operated on subtotal and total mastectomy and to compare the regularity of BSE with the severity of breast cancer. The subjects were 163 patients with operated on mastectomy who participated were interviewed in the S university Hospital. The collected data were analyzed by descriptive statistics and t-test, One-way ANOVA and Pearson Correlation with SPSSWIN program. Results were obtained as follows: 1. There was no statistical difference between in the regular group of the mammography and the regular BSE group(F=0.558, P=0.458). 2. There was statistical difference between the method of detection and the severity of the breast cancer(F=3.359, P=0.011). 3. There was statistical difference between regularity of the BSE and the severity of breast cancer(F=3.301, P=0.019). 4. There was showed higher severity of the breast cancer in the elderly patients(r=0.172, P=0.019). 5. There was showed higher severity of the breast cancer in the lower educational level(r=-0.170, P=0.033). According to this study need to the development of the educational program about the BSE and the future research about the regular BSE of the high risk group in the breast cancer.

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Perceived Performance of HACCP for School Foodservice Managers in Daejeon (대전지역 학교급식 영양사의 HACCP 직무관련 수행도 평가)

  • Kim, Young-Ok;Kwon, Sun-Ja;Ly, Sun-Yung
    • Korean Journal of Human Ecology
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    • v.18 no.1
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    • pp.223-236
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    • 2009
  • The purpose of this study was to improve the sanitary management of school foodservice. A survey questionnaire was administered to 153 dietitians from elementary, middle and high schools in the Daejeon area. The questions were categorized into four fields: 'General characteristics', 'Facility and equipment set up at the schools studied', 'Performance of CCP(criticai control point)s' and 'Reasons of barriers to HACCP(hazard analysis of critical control points) implementation'. The results were as follows. Most of the subjects were the dietitians of elementary school(56.9%), were university graduates(51.0%) and were in their thirties(58.2%). The average length of their career had been 5.8 years. The average ratio of students per dietitian was 1,163. The average ratio of students per full-time employee was 124. The ratio of self-operated management was 90.2 %. The CCP7(assembling and serving) received the highest performance score, while the performance score of CCP2(management of potentially hazardous foods) was the lowest. Eighty-four percent of the surveyed school foodservices did not have pre-preparation rooms. The school foodservice operations were not well equipped with hot/cold holding equipments. Self-operated management scored higher on almost all sections(CCP1-CCP7). Contracted management scored highest on CCP8. The higher the age and career of the subject were, the higher were all the CCP performance scores. The reasons of barriers to HACCP implementation were lack of understanding of standards CCP1 and CCP2, workers' lack of cooking knowledge, and lack of information about school foodservice.

Development and Performance Test of SOFC Co-generation System for RPG (SOFC를 이용한 가정용 열병합 발전시스템 개발 및 성능시험)

  • Lee, Tae-hee;Choi, Jin-Hyeok;Park, Tae-Sung;Choi, Ho-Yun;Yoo, Young-Sung
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.361-364
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    • 2009
  • KEPRI has studied planar type SOFC stacks using anode-supported single cells and kW class co-generation systems for residential power generation. A 1kW class SOFC system consisted of a hot box part, a cold BOP part and a water reservoir. A hot box part contains a SOFC stack made up of 48 cells with $10{\times}10cm^2$ area and ferritic stainless steel interconnectors, a fuel reformer, a catalytic combustor and heat exchangers. Thermal management and insulation system were especially designed for self-sustainable operation. A cold BOP part was composed of blowers, pumps, a water trap and system control units. When a 1kW class SOFC system was operated at $750^{\circ}C$ with hydrogen, the stack power was 1.2kW at 30 A and 1.6kW at 50A. Turning off an electric furnace, the SOFC system was operated using hydrogen and city gas without any external heat source. Under self-sustainable operation conditions, the stack power was about 1.3kW with hydrogen and 1.2kW with city gas respectively. The system also recuperated heat of about 1.1kW by making hot water. Recently KEPRI developed stacks using $15{\times}15cm^2$ cells and tested them. KEPRI will develop a 5 kW class CHP system using $15{\times}15cm^2$ stacks by 2010.

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Task Analysis on Foodservice , Clinical Nutrition Service in Hospital Dietetic Departments (병원 영양부서의 급식 및 임상영양 서비스의 중점관리 요인)

  • Hong, Wan-Su;Kim, Hye-Jin;Jang, Eun-Jae
    • Journal of the Korean Dietetic Association
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    • v.6 no.2
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    • pp.148-160
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    • 2000
  • The purpose of this research was to analyze the tasks on foodservice ․ clinical nutrition service in hospital dietetic departments. A survey of 30 hospital food and nutrition service departments was undertaken and detailed informations were collected from each, including surveys of 176 dietitians and 30 foodservice managers. Statistical data analysis was completed using the SAS/win 6.11 package for descriptive analysis and t-test. The results of this study can be summarized as follows : Regarding dietitian's training period, 38.6% dietitians answered that they spent 1~2 years in mastering food service management. 28.4% dietitians replied that they needed 2~3 years in learning clinical nutrition management. It was shown that 48.9% dietitians were engaged in food service management, while 26.7% were engaged in clinical nutrition and 26.7% were engaged in both. The 13 elements of food service management showed low performance level. These elements were food temperature, food intake, menu selection, contaminated substances and serving mistake and reliance on hospital food. These should be controlled with caution. The average score of dietitian's life satisfaction within the work place was 3.42 out of 5. The most dissatisfactory element was physical environment of the workplace. 5 elements for improving nutrition service activities showed low performance level with high importance score. Problem analysis showed low difference score between importance and performance level. Hospitals under contract foodservice management received higher points on clinical nutrition performance(P<.05) than hospitals under self-operated foodservice management.

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