• 제목/요약/키워드: resistance management

검색결과 994건 처리시간 0.026초

육각 나선형 박막 인덕터의 주파수 특성에 관한 연구 (Study on Frequency Characteristics of Hexagonal Spiral Thin-film Inductor)

  • 김재욱;김희철
    • 한국정보전자통신기술학회논문지
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    • 제10권5호
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    • pp.402-408
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    • 2017
  • 본 논문에서는 무선 신호전송을 위한 비접촉 방식의 AC 커플링 기반 육각 나선형 박막 인덕터의 주파수 특성을 분석하였다. 사각 나선형 인덕터와 육각 나선형 인덕터에 대하여 권선수 변화, 도체 선 폭 및 선 간격을 변화에 따른 주파수 특성을 비교 분석하였다. 육각 나선형 인덕터는 사각 나선형 인덕터와 비교하여 동일한 인덕턴스를 갖기 위하여 더 많은 권선수를 갖게 되지만 전체적인 도선의 길이는 짧아지게 된다. 이는 자기인덕턴스는 감소하고 상호인덕턴스가 증가하여 전체적인 인덕턴스는 같은 값을 가질 수 있다. 또한 전체적인 도선의 길이가 짧아지고 자기저항이 감소하므로 품질계수와 자기공진주파수의 성능을 확보할 수 있다. 제안된 육각 나선형 박막 인덕터는 2GHz에서 3.54nH의 인덕턴스와 5.0GHz에서 최댓값 14.00의 품질계수를 가지며, 약 11.3GHz에서 자기공진주파수를 가진다.

Role of Neoadjuvant Chemotherapy in the Management of Advanced Ovarian Cancer

  • Zhao, Dan;Wu, Ling-Ying;Wang, Xiao-Bing;Li, Xiao-Guang
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권6호
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    • pp.2369-2373
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    • 2015
  • Objective: To analyze efficacy of neoadjuvant chemotherapy for advanced ovarian cancer. Materials and Methods: A total of 107 patients with advanced ovarian cancer undergoing cytoreductive surgery were divided into a neoadjuvant chemotherapy group (n=61) and a primary debulking group (n=46) and retrospectively analyzed. Platinum-based adjuvant chemotherapy was applied to both groups after cytoreductive surgery ande overall and progression-free survival times were calculated. Results: No significant difference was observed in duration of hospitalization ($20.8{\pm}6.1$ vs. $20.2{\pm}5.4$ days, p>0.05). The operation time of neoadjuvant chemotherapy group was shorter than the initial surgery group ($3.1{\pm}0.7$ vs. $3.4{\pm}0.8$ h, p<0.05). There were no significant differences in median overall survival time between neoadjuvant chemotherapy group and surgery group (42 vs. 55 months, p>0.05). Similarly, there was no difference in median progression-free survival between neoadjuvant chemotherapy group and surgery group (16 vs. 17 months, p>0.05). The surgical residual tumor size demonstrated no significant difference between initial surgery and neoadjuvant chemotherapy groups (p>0.05). Multivariate analysis showed that more than 3 cycles of regimen with neoadjuvant chemotherapy was associated with more resistance to chemotherapy compared with patients without receiving neoadjuvant chemotherapy (OR: 5.962, 95%CI: 1.184-30.030, p<0.05). Conclusions:Neoadjuvant chemotherapy can shorten the operation time. However, it does not improve survival rates of advanced ovarian cancer patients.

플래시 메모리 기반의 DBMS를 위한 동적 블록 할당에 기반한 효율적인 로깅 방법 (An Efficient Logging Scheme based on Dynamic Block Allocation for Flash Memory-based DBMS)

  • 하지훈;이기용;김명호
    • 한국정보과학회논문지:데이타베이스
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    • 제36권5호
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    • pp.374-385
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    • 2009
  • 플래시 메모리는 비휘발성이면서도 작고 가벼우며, 전력 소모가 적고 충격에 강하다는 장점 등으로 인해 휴대 기기를 포함한 다양한 기기의 저장매체로 사용되고 있다. 그러나 플래시 메모리는 하드디스크와는 달리 제자리 갱신이 불가능하고, 읽기 연산에 비해 쓰기 및 지우기 연산이 매우 느리기 때문에, 기존의 하드 디스크를 기반으로 설계된 데이터베이스 시스템은 플래시 메모리 상에서 최적의 성능을 내기 어렵다. 플래시 메모리 상에서 데이터베이스의 성능을 극대화하기 위해, 어떤 데이터에 변경이 발생하면 원래 위치의 데이터를 덮어쓰는 대신, 해당 데이터의 변경 사항에 대한 로그만을 다른 위치에 기록하는 방식들이 제안되었다. 본 논문에서는 플래시 메모리 기반의 데이터베이스 시스템을 위한 효율적인 로깅 방법을 제안한다. 제안하는 방법은 기존 방법들과 달리, 로그만을 저장하는 로그 블록들을 별도로 두고 데이터의 변경에 따라 발생하는 로그를 로그 블록들에 고르게 분포시킨다. 이를 통해 제안하는 방법은 페이지 쓰기 및 블록 지우기 연산의 횟수를 크게 감소시킬 수 있다. 합성 데이터와 TPC-C 벤치마크 데이터를 사용한 실험을 통해, 제안하는 방법은 기존의 방법에 비해 좋은 성능을 나타냄을 보였다.

Milk casein과 수용성 폴리우레탄 resin을 이용한 산업 안전 방재용 하이브리드 film의 합성 및 기계적 물성에 관한 연구 (Study on Mechanical Properties of Hybrid Resins by Milk Casein and Waterborne Polyurethane for Safety Management of Industrial Disaster)

  • 이주엽;김기준
    • 한국응용과학기술학회지
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    • 제29권2호
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    • pp.356-363
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    • 2012
  • 본 연구에서는 밀크 카제인과 WPU를 이용한 하이브리드 수지를 합성하였다. 합성한 하이브리드 수지를 피혁(Full-Grain) 표면에 코팅을 하여 카제인이 하이브리드수지에 어떤 영향을 주는지에 대해 분석 하였다. 내용제성 테스트 데이터에 의하면 WPU 와 하이브리드 수지 양쪽 모두 높은 물성치를 나타내었다. 인장 강도 측정치에서는 WPU 단독 결과(2.130 $kg_f/mm^2$)가 가장 낮은 수치를 나타내었으며, WPC-3(WPU 91: casein resin 9)의 경우가 가장 높은 인장력(2.191 $kg_f/mm^2$)을 나타내었다. 또한 내마모도 측정에서는 WPC-3(50.090 mg.loss)가 좋은 물성값을 나타내었다. 연실률의 경우 WPU(637 %) 단독 코팅물의 분석값이 가장 높은 637%로 알 수 있었다.

Effects of Pinitol Supplementation and Strength Training on Anaerobic Performance and Status of Energy Substrates in Healthy Young Men

  • Lee, Dae-Taek;Lee, Woon-Yong
    • Nutritional Sciences
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    • 제8권3호
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    • pp.189-195
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    • 2005
  • To assess the effect of pinitol supplementation and strength training for two weeks on the anaerobic capacity during and after exercise, and improvement of glucose metabolism during the recovery period of muscular fatigue with repeated acute bouts of cycling exercise, a total of 24 healthy young men were recruited and randomly and equally divided into three groups; pinitol supplementation group (PSG), placebo group (PLG), and control group (CON). Using a randomized double-blinded design, subjects in PSG were provided pinitol supplement, consumed orally 1.2 g/day, and participated in the resistance exercise program and cycling exercise for two weeks. Subjects in PLG underwent the same protocol as those in PSG but consumed the same amount of placebo. No supplementation and exercise program was given to CON. Before and after the intervention, all subjects were tested for their anaerobic capacities evaluated by Wingate test twice separated by 30 min. During the test, peak anaerobic power (PP), mean anaerobic power, total work, and fatigue index were evaluated During resting and recovery, blood samples were drawn and plasma pinitol, myo-inositol, chiro-inositol, insulin, free fatty acid, glucose, and lactate levels were analyzed After two weeks, PP and relative PP of the second biking were improved from the first biking in PSG only (p<0.05). No changes were found in all other variables of Wingate test in all groups. No statistical differences between groups and pre- and post-intervention were observed in concentrations of pinitol, myo-inositol, and chiro-inositol, but pinitol concentration was higher during recovery compared to the baseline in all groups and testings (p<0.05). Lactate level during recovery was higher than the resting level, but no other blood parameters were significantly changed. In conclusion, two weeks of pinitol supplementation in conjunction with short duration of anaerobic training in healthy young men did not induce any obvious benefits in terms of anaerobic capacity and energy metabolism Individual and/or population susceptibility may be one factor responsible for adopting pinitol supplementation.

SWOT 분석에 기반한 한국형 MOOCs 설계요소 연구 (A SWOT Analysis of Design Elements of Korean MOOCs)

  • 임걸;김미화
    • 디지털융복합연구
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    • 제12권6호
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    • pp.615-624
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    • 2014
  • 최근 MOOCs(Massive Open Online Courses)는 강의공개운동의 양적, 질적 팽창을 주도하며 고등교육 혁신의 새로운 대안으로 자리잡고 있다. KOCW를 통하여 강의공개의 이상을 실천하고 있는 우리나라에서도 MOOCs 발전에 따른 KOCW의 진화가 기대되고 있다. 그러나 미국을 기반으로 성장하고 있는 MOOCs가 국내 여건이 고려되지 않은 상태로 이식되거나 국내 대학강의 공개가 OCW 환경에서 더 이상 진화하지 못할 경우, 그 과정에서 갈등과 저항이 발생할 가능성이 있으며, 교육의 대중화 및 개별화 등의 이상 구현의 기회를 제공하는 MOOC의 장점을 수용할 수 없게 된다. 따라서 최신의 MOOCs 경향을 수용하는 과정에 있어 국내 환경이 고려된 분야별 대응 및 발전전략을 수립하는 것은 고등교육 발전에 영향을 미칠 수 있는 중요한 연구이다. 이를 위해 본 연구에서는 SWOT 분석을 통해 우리나라의 배경을 살펴보고, 이 결과에 근거하여 한국형 MOOCs 개발시 요구되는 설계요소들을 연구하였다.

동결/해동 조건에서 기체확산층이 고분자전해질연료전지의 내구성에 미치는 영향에 관한 연구 (Investigation of Gas Diffusion Layer Effects on the Freeze/Thaw Condition Durability in PEFCs)

  • 임수진;박구곤;박진수;손영준;임성대;양태현;김창수
    • 한국수소및신에너지학회논문집
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    • 제20권4호
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    • pp.309-316
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    • 2009
  • The effect of gas diffusion layers (GDLs) on the freeze/thaw condition durability in polymer electrolyte fuel cells (PEFCs) were investigated. For this purpose, three kinds of GDLs, such as, felt, paper and cloth types with different basic properties have been first prepared, then the changes in the properties and performance of cells was observed during the freeze/thaw cycles ranging from -30 to $70^{\circ}C$. The performance evaluations were conducted by using the single cells consisting of different GDLs. The performance degradation and the cell resistance increase could be directly correlated. The physical destruction of electrode was shown by SEM analysis. The mechanically supporting ability on the interface between the cell components can help enhancing the durability of PEFCs in the freeze/thaw condition.

노인의 의.식.주생활 및 심리적 적응을 위한 이상적 모델개발 연구 -양로원을 중심으로- (The Development of a Retirement Home Model with Emphasis on Clothing, Nutrition, Housing, and Psychological Dimension)

  • 윤복자
    • 대한가정학회지
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    • 제27권4호
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    • pp.167-191
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    • 1989
  • The present study was conducted to devlop and appropriate retirement home model for the elderly in terms of clothing and textiles; nutrition, health, and foodservice; housing and environment; and psychological adaptation. Specifically, the purposes of the study were: 1) to provide basic guidelines for clothing by comparing the clothing behavior of the elderly living in the retirement home and those living in their own homes with family, 2) to provide basic guidelines for balanced diet and effective foodservice, 3) to develop an ideal life space and facilities, and 4) to assess the psychological characteristics of the elderly. Questionnaires, observation, experimental method, and survey of literature were used for the study. Clothing behavior showed that the elderly were much concerned about clothing, and they preferred comfortable as well as fashionable designs. The elderly in the retirement homes complained of a lack of quantity and variety in clothing. They preferred natural fiber rather than blended fabrics. Flame resistance, thermal insulation, and flexibility of textile fabrics were found to be prime considerations in manufacturing and selecting clothing materials for the elderly. The health status of the surveyed elderly was generally good, but some poor eating habits were observed. Dietary nutrients intakes were generally sufficient, but several nutrients intakes were insufficient. The level of equipment in the kitchens of the institutions was low. Furthermore, the employment rate of dietitians in institutional settings was extremely low. This resulted in a lack of systematic foodservice management. Residents in the institution were generally satisfied with present life space and facilities but this was mainly because of abandonment, adaptation, and past experience. Optimal allocation of residents per bedroom and an adequate design for storage, bathroom, utility room, and dining room were recommended. The comparison of psychological status of the elderly living at home was more stable than those living in an institution. The emotional state of the elderly living in the institution was characterized by loneliness; they did not have close interpersonal relationships or future plans. An appropriate model for the elderly was developed on the basis of these findings.

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항타 말뚝에서 항타관리시스템(Pile Installation Recorder-Driven Pile)의 적용성에 관한 연구 (Study on Application of PIR-D(Pile Installation Recorder-Driven Pile) in Driven Pile)

  • 박봉근;박민철;최용규
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2004년도 춘계학술발표회
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    • pp.28-35
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    • 2004
  • Driven pile has the excellent bearing characteristics and good economics, so it is known as the comparative piling method. To use the advantages of driven pile fully, it is necessary to perform the proper construction management. Engineers must drive pile to the proper bearing layer with proper blow energy and measure the blow count and penetration per certain depth to analyze the bearing capacity and driveability. In conventional method, these parameters have been measured manually so it was difficult to get good accuracy. After PIR-D(Pile Installation Recorder-Driven Pile) was attached to the driving equipment, the hammer efficiency, blow count and penetration in blow/10cm were measured automatically. In this paper, to givethe rational judgement criteria of bearing layer, driveability, blow/10cm according to pile depth during pile driving, the some relationship between the driving resistance and ground layer distribution was analyzed. The ground investigation during piles (PHC ${\Phi}450,\;{\Phi}400\;&\;Steel\;Pile\;{\Phi}609{\ast}16t$) installation in the marine clay layer in Incheon, the sandy soil layer in Yongin and the tuff layer in Pusan was done. And measuring hammer efficiency not doing recently, we could compare hammer efficiency(Eh) by PIR-D and energy transfer ratio(ETR) by Pile Dynamic Analyzer(PDA).

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매트릭스 두께가 MCFC 장기 성능에 미치는 영향 (The effect of the matrix thickness on the long term performance of MCFC)

  • 김윤영;한종희;윤성필;남석우;임태훈
    • 한국수소및신에너지학회논문집
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    • 제16권2호
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    • pp.170-179
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    • 2005
  • Electrolyte loss is considered as one of the major obstacles limiting the life time of molten carbonate fuel cells (MCFCs). Unit cells with an effective area of 100 $cm^2$ were prepared and were operated to determine the optimum matrix thickness which contains the maximum amount of electrolyte without serious preformance loss caused by high resistance. Matrices with different thickness, 1.45, 1.8, and 2.3 mm, were used in unit cells and those cells were operared about 5000, 10000, and 4000 hrs. The unit cell used 1.8 mm thick matrix showed 0.85 V (at 150 mA/$cm^2$) as the intial performance and this cell voltage is not lower than the cell voltage obtained in the cell with 1 mm thick matrix. This cell was operated for 10000 hrs. The cell used 1.45 mm thick matrices showed 16.6 % in the electrolyte loss after 5000 hr operation. In the case of the cell with 2.3 mm thick matrix, the initial cell voltage was below 0.80 V (at 150 mA/$cm^2$). For thermal cycle test, the gas crossover amount of unit cell used 1.8 mm thick matrix was much less than that of the cell with 1.0 mm thick matrix.