• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.432-441
• /
• 2017

Grid voltage feedforward is extensively used for controlling grid-connected converters. However, the conventional voltage feedforward control reduces the stability margins of the converter connected to a high-impedance grid. The effect mechanism of voltage feedforward on the grid-connected converter control under high-inductive conditions of the grid impedance is clearly explained in this study using the equivalent transformations of control block diagrams. Results show that the delay produced by the digital control is the root cause of this effect. An improved voltage feedforward strategy, in which a bandpass filter (BPF) is introduced into the feedforward path, is proposed to strengthen the converter's robust stability against grid impedance variations. The selection method of the BPF's bandwidth is also provided considering the tradeoff between the response speed to the grid voltage sag and the system's robust stability. The converter can work stably over a wide range of the grid impedance through the proposed approach. Simulation and experimental results fully verify the effectiveness of the BPF-based voltage feedforward strategy.

• Steel and Composite Structures
• /
• 제26권2호
• /
• pp.197-211
• /
• 2018

The study presents the earthquake performance of the Bosphorus Bridge under multi-point earthquake excitation considering the spatially varying site-specific earthquake motions. The elaborate FE model of the bridge is firstly established depending on the new considerations of the used FEM software specifications, such as cable-sag effect, rigid link and gap elements. The modal analysis showed that singular modes of the deck and the tower were relatively effective in the dynamic behavior of the bridge due to higher total mass participation mass ratio of 80%. The parameters and requirements to be considered in simulation process are determined to generate the spatially varying site-specific ground motions. Total number of twelve simulated ground motions are defined for the multi-support earthquake analysis (Mp-sup). In order to easily implement multi-point earthquake excitation to the bridge, the practice-oriented procedure is summarized. The results demonstrated that the Mp-sup led to high increase in sectional forces of the critical components of the bridge, especially tower base section and tensile force of the main and back stay cables. A close relationship between the dynamic response and the behavior of the bridge under the Mp-sup was also obtained. Consequently, the outcomes from this study underscored the importance of the utilization of the multi-point earthquake analysis and the necessity of considering specifically generated earthquake motions for suspension bridges.

• 한국독어학회지:독어학
• /
• 제2집
• /
• pp.185-206
• /
• 2000

Das Wortspiel $hei{\ss}t$ die spielerische $Ver\"{a}nderung$ eines Wortes zum Zwecke $\"{u}berraschender$ Wirkungen, und die Werbetexter betrachten es monentan als ein beliebtes, wirkungsvolles Ausdrucksmittel $f\"{u}r$ die Werbeanzeigen. (1) Sag mal, wie war eigentlich dein erstes Mal? Und wie oft machst du es in der Woche? Und was sagt deine beste Freundin dazu? -Gesichtsreinigungsmittel Clearasil Complete(Janich, 1999:146) (2) 대장님 힘 내세요! 뒷일은 제가 책임지겠습니다. -아락실 (3) 당신은 철없는 여자. -헤모큐 Das Wortspiel $l\"{a}{\ss}t$ den Referenzbezug ausweiten, vage oder $ungew\"{o}hnlich$ werden. Dadurch werden konventionelle Referenzerwartungen der Rezipienten verletzt und unterbrochen. Wortspiele mit Homonyme, Polyseme, Wortkreuzungen, und Referenzspiele sind sehr $h\"{a}ufig$, und die syntaktische und typographische Spiele dagegen eher selten. Die Wirkung des Wortspiel beruht auf die $Ambiguit\"{a}t$ eines Wortes. Aber zwischen der$Ambiguit\"{a}t$ und der Vagheit gibt es den $un\"{u}bersehbaren$ referenziellen Unterschied. $W\'{a}hrend$ diese, die durch die pragmatische Mehrdeutigkeit oder die Unbestimmtheit charakterisiert ist, mit der in einer $\"{A}u{\ss}erung ausgedr\"{u}ckten$ Vorstellung zu tun hat, handelt es bei jener um die Probleme der linguistischen Kategorien an, die unter lexikalischem, semantischem, und syntaktischem Aspekt mehrfach zu spezifizieren sind. Daher $k\"{o}nnen$ den wortspielerischen $Ausdr\"{u}cken$ mehere Interpretationsmoglichkeiten zugeordnet werden. Durch Wortspiele wird die Eindeutigkeit eines Wortes absichtlich aufgehoben, so $da{\ss}$ mehere denotativen Bedeutungen aktiviert werden. Dabei liegt eine semantische Konzentration oder ein semantisches Spannungsverhaltnis vor, Diesbezuglich $erf\"{u}llt$ das Wortspiel zugleich die Funktion, Aufmerksamkeit des Rezipienten auf den geworbenen Inhalt zu wecken, und $f\"{o}rdert$ das Interesse am Werbetext.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제20권1호
• /
• pp.13-17
• /
• 2010

Ten numbers of plants, based on their medicinal value, were used to test their efficacy against virosis (caused by cytoplassmic polyhedrosis virus) in tasar silkworm, Antheraea mylitta Drury. in indoor rearing conditions. The aqueous extracts of leaf of Azadirichita indica (neem), Acharanthus aspera, Psoralea corylifolia, Asparagus racemosus, Adhatoda zelanica (Basak), Andrographis paniculata (Kalmegh), Moringa oilephera (sahjan), whole plant of Phyllanthus urinaria (Bhuiamla), Centella asiatica (Veng sag) and Curcuma longa (Haldi powder) in different concentrations were used for containment of virosis in silkworm larvae. The tasar silkworm larvae were orally inoculated with PIBs ($1\times10^6$) of AmCPV in $2^{nd}$ instar and treated with plant extracts in each instar ($2^{rd}$ instar onwards). The mortality due to virosis was recorded during larval period. The plant extracts, irrespective of their concentrations, were found effective in suppressing the virosis where P. urinaria reduced the virosis to 56.90% followed by A. paniculata (53.82%) and least in C. asiatica (5.15%). The lowest pooled larva mortality 36.99% was recorded in the treatment of P. urinaria. Comparatively higher larva mortality 39.91% was observed with the treatment of A. paniculata. The highest larva mortality in treatment was with C. asiatica (81.99%). In treated control larva mortality was 86.50%.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• 제21권4호
• /
• pp.271-277
• /
• 2018

Purpose: Familial Mediterranean fever (FMF) is an auto inflammatory disease characterized by periodic fever, synovitis and serositis. Patients may be admitted to gastroenterology units due to gastrointestinal symptoms. In this study; we aimed to analyze endoscopic findings and diagnostic utility of endoscopic procedure in children with FMF. Methods: Patient with FMF that was performed endoscopy for the gastrointestinal symptoms were included to the study (39 of 164 patients, 53 procedure). A control group was randomly designed as age and gender matched four endoscopic procedures per one endoscopic procedure of patients with FMF (n=212). Results: No different was found between the patients and control group in esophagogastroscopy findings. However, the diagnosis of gastrointestinal pathology was made by esophagogastroscopy in 46.2% patients. Colonoscopic examination revealed that the frequency of inflammatory bowel disease (IBD) was higher in undiagnosed patients compared to both the control group (50.0% vs. 6.9%, p<0.05, odds ratio [OR]:13.4 and 95% confidence inteval [95% CI]: 2.1-84.3) and the patients under colchicine treatment (50.0% vs. 8.3%, p<0.05, OR: 11 and 95% CI: 0.8-147.8). Colonoscopic procedure that was made after the diagnosis was found to provide contribution by 16.7% in determining the etiology of the additional symptoms. Conclusion: Patients with FMF may be admitted to pediatric gastroenterology outpatient clinic prior to diagnosis or during the follow-up period. The frequency of IBD is high in undiagnosed patients with FMF. Endoscopic procedures may be helpful in these patients for the diagnosis accompanying mucosal lesions.

• 한국식품과학회지
• /
• 제22권1호
• /
• pp.38-43
• /
• 1990

녹두전분의 농도(5-8%, 건량기준)와 가열온도$(80-95^{\circ}C$)가 전분의 리올로지에 미치는 영향을 조사하였다. 녹두전분은 농도에 관계없이 아밀로그래프의 최고점도를 보이지 않았고 가열 중 점도는 계속 증가하였다. 전분호화액은 항복응력을 가진 의가소성 유체의 성질을 보였고, 점조도지수는 농도와 가열온도가 증가할수록 증가하였으나, 유동지수는 반대로 감소하였다. 전분 겔을 $4^{\circ}C$에 저장하는 동안 겔의 수축정도는 농도와 가열온도가 증가할수록 감소하였다. 아밀로그래프를 이용하여 $95^{\circ}C$에서 15분간 호화시켜 만든 농도 7과 8%의 겔의 초기경도는 6% 겔보다 2배 이상 높았으나, $4^{\circ}C$에서의 노화속도는 농도와 가열온도에 크게 영향을 받지 않았다.

• 한국광학회지
• /
• 제25권5호
• /
• pp.273-278
• /
• 2014

일련의 국부영역으로부터 이차미분값을 획득하여 전체 형상을 복원하는 측정법을 제안하였다. 측정시 기울기가 제거된 국부형상에 대해 곡률과 이차미분이 동일시 되는 점을 이용하여, 3개의 이차미분값으로부터 직교하는 2방향을 따라 3차원형상을 복원할 수 있는 알고리즘을 구현하였다. 임의로 발생시킨 Zernike다항식의 계수로 자유곡면형상을 생성시키고, 구현된 알고리즘을 적용함으로써 검증과정을 수행하였다. 적용한 결과 최대 0.8 mm Sag를 갖는 직경 200 mm영역의 자유곡면형상에 대해 RMS 19 nm 형상복원오차를 갖고 복원됨을 확인하였다. 측정오차에 대한 복원오차 민감도를 진단하기 위해 SNR(Signal-to-Noise Ratio) 16의 가우시언 랜덤 노이즈를 부여한 후, 복원되는 형상의 오차를 진단한 결과, 197 nm의 형상복원오차가 발생함을 확인하였다.

• 한국공간구조학회논문집
• /
• 제17권2호
• /
• pp.21-32
• /
• 2017

The objective of this study is to analysis the mechanical characteristics on the geometric nonlinear behavior of radial cable roof systems for long span retractable cable roof structures. The retractable roof is designed as a full control system to overcome extreme outdoor environments such as extreme hot or cold weather, strong wind or sunlight, and the cable roof greatly can reduce roof weight compared to other rigid structural system. A retractable cable roof system is a type of structures in which the part of entire roof can be opened and closed. The radial cable roof is an effective structural system for large span retractable roofs, the outer perimeter of the roof is a fixed membrane roof and the middle part is a roof that can be opened and closed. The double arrangement cables of a radial cable truss roof system with reverse curvature works more effectively as a load bearing cables, the cable system can carry vertical load in up and downward direction. In this paper, to analyze the mechanical characteristics of a radial cable roof system with central posts, the authors will investigate the tensile forces of bearing cables, stabilized cables, ring cables, and the deflection of roof according to the height of the post or hub that affects the sag ratio of cable truss. The tensile forces of the cables and the deflection of the roof are compared for the cases when the retractable roof is closed and opened.

• 의학교육논단
• /
• 제9권2호
• /
• pp.29-40
• /
• 2007

Purpose: This study analysed the intention of medical students career choice, educational programmes, and mentoring and counseling system for career planning at Yonsei medical school in Korea. Methods: The data were collected based on four separate graduation questionnaires at Yonsei medical school in the years of 2005, 2006, 2007, and 2008. The number of the survey was 130 in 2005, 130 in 2006, 153 in 2007, and that of the latest was 120 in 2008. We analysed the career intention on medical specialties and activities, and perceptions of important factors in choosing medical specialty. Results : The results which can be drawn from this study are these: firstly. students had more intention for choosing clinical medicine as university faculty than any other activities. While male students preferred to major in surgery, neurosurgery, orthopedic surgery, urology, otorhinolaryngology, female students in internal medicine, neurology, anesthesiology and pain medicine, diagnostic radiology, laboratory medicine. Secondly, students perceived that the most important factor which can influence on choosing a medical specialty was individual factor such as one's interests and concerns, values, and aptitudes. In stead, they relatively less perceived mentor and role model's effects on choosing a medical specialty compared to those of the United States of America. Third, the career planning at Yonsei medical school was evaluated well, especially educational programmes for career planning such as self assessment programme, elective(specialized) courses, and conversation with a senior programme. Conclusions: Unexpectedly, there are high demands for career planning by medical students. Therefore, we will reorganize systematic devices for career planning such as mentoring and counseling system at medical school.

• 한국도로학회논문집
• /
• 제10권2호
• /
• pp.125-133
• /
• 2008

차량의 주행속도는 설계일관성을 평가하는 주요한 척도로 활용되며 그 중 곡선반경은 여러 연구에서 공통적으로 제시한 주된 요인으로 나타났다. 이에 본 연구에서는 복합선형에서 설계속도별 적정 평면곡선반경 범위기준을 정립하고 운전자의 인지 행태를 나타낼 수 있는 인지반경을 정립하여 입체선형에서 적합한 평면곡선반경을 제시하고자 한다. 첫째, 본 연구에서는 저속차량의 방해요소를 최소화하기 위하여 입체선형을 고려한 도로의 임의지점에서 횡방향 미끄럼 마찰계수와 주행방향 미끄럼 마찰계수를 동시에 고려하여 설계속도와 종단경사별 평면곡선반경을 제시하였다. 둘째, 본 연구에서는 곡선부 인지반경을 통하여 평면 곡선부와 편평한 종단경사가 조합된 경우, 평면 곡선부와 종단곡선부가 조합된 경우를 비교한 후, 곡선부 인지반경을 산정하여 설계속도별 적정 평면곡선반경과 인지반경 비율을 제시하였다.