• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.63-72
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• 2006

The purpose of this raper is to address the negative impedance instability in DC/DC converters. We present the negative impedance instability of PWM DC/DC converters loaded by constant power loads (CPLs). An approach to design digital controllers for DC/DC converters Is presented. The proposed method, called Power Alignment control technique, is applied to DC/DC step-down choppers operating in continuous conduction or discontinuous conduction modes with CPLs. This approach uses two predefined state variables instead of conventional pulse width modulation (PWM) to regulate the output voltage. A comparator compares actual output voltage with the reference and then switches between the appropriate states. It needs few logic gates and comparators to be implemented thus, making it extremely simple and easy to develop using a low-cost application specific integrated circuit (ASIC) for converters with CPLs. Furthermore, stability of the proposed controllers using the small signal analysis as well as the second theorem of Lyapunov is verified. Finally, simulation and analytical results are presented to describe and verify the proposed technique.

• BMB Reports
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• 제39권3호
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• pp.329-334
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• 2006

RNAi (RNA interference) has become a popular means of knocking down a specific gene in vivo. The most common approach involves the use of chemically synthesized short interfering RNAs (siRNAs), which are relatively easy and fast to use, but which are costly and have only transient effects. These limitations can be overcome by using short hairpin RNA (shRNA) expression vectors. However, current methods of generating shRNA expression vectors require either the synthesis of long (50-70 nt) costly oligonucleotides or multi-step processes. To overcome this drawback, we have developed a one-step short-oligonucleotides-based method with preparation costs of only 15% of those of the conventional methods used to obtain essentially the same DNA fragment encoding shRNA. Sequences containing 19 bases homologous to target genes were synthesized as 17- and 31-nt DNA oligonucleotides and used to construct shRNA expression vectors. Using these plasmids, we were able to effectively silence target genes. Because our method relies on the onestep ligation of short oligonucleotides, it is simple, less error-prone, and economical.

• 한국군사과학기술학회지
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• 제27권1호
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• pp.43-50
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• 2024

Large planar military antenna boasts a range of electrical components, including TRA(Transmit-Receive Assembly), signal processors, etc. which engage in computations and calculations. These processes generate a significant amount of heat, leading to unforeseen consequences for the equipment. To mitigate these adverse effects, it's imperative to implement a cooling system that can effectively reduce heat-related issues. Given the antenna's intricate nature and the multitude of components it houses, a two-step estimation process is necessary. The first step involves a comprehensive model calculation to determine the total flow characteristics, while the second step entails a thermal analysis of individual TRA set. In this study, we depicted an antenna set using simplified 3D models of its components, considering their material and thermal properties. The sequential analysis process facilitated the calculation of branched flow rates, providing insights into the individual TRA. This approach also allowed us to design a cooling system for the TRA set, assessing its thermal stability in high-temperature environments. To ensure the optimal performance of TRA, breaking down the analysis into stages based on the cooling system's structure can assist operators in predicting numerical results more effectively.

• 정보처리학회논문지A
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• 제11A권1호
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• pp.97-108
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• 2004

본 논문은 자바 프로그램에서 논리적인 오류를 발견하기 위해 알고리즈믹 디버깅 기술의 이용을 제안한다. 알고리즈믹 디버깅 기술은 원시프로그램으로부터 실행 트리를 생성하고, 실행 트리로부터 프로그램 내에 포함된 논리적인 오류를 하향식 방법으로 발견하는 반자동화 디버깅기술이다. 따라서 알고리즈믹 디버깅 기술은 다양한 프로그래밍 언어에 알맞은 실행 트리를 생성하는 것이 중요하다. 주 논문에서는 자바 프로그램으로부터 실행 트리를 생성하는 방법을 제안하고 예제론 통해서 자바 프로그램을 위한 알고리즈믹 디버깅 기술을 확인한다. 이 접근은 전통적인 순차적 디버깅 기술보다 사용자와 디버깅 시스템 사이에서 상호작용의 수를 줄일 수 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.114-114
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• 2020

Water contamination in a water distribution network (WDN) is harmful since it directly induces the consumer's health problem and suspends water service in a wide area. Actions need to be taken rapidly to countermeasure a contamination event. A contaminant source ident ification (CSI) is an important initial step to mitigate the harmful event. Here, a CSI approach focused on determining the contaminant intrusion possible location and time (PLoT) is introduced. One of the methods to discover the PLoT is an inverse calculation to connect all the paths leading to the report specification of a sensor. A filtering procedure is then applied to narrow down the PLoT using the results from individual sensors. First, we spatially reduce the suspect intrusion points by locating the highly suspicious nodes that have similar intrusion time. Then, we narrow the possible intrusion time by matching the suspicious intrusion time to the reported information. Finally, a likelihood-score is estimated for each suspect. Another important aspect that needs to be considered in CSI is that there are inherent uncertainties, such as the variations in user demand and inaccuracy of sensor data. The uncertainties can lead to overlooking the real intrusion point and time. To reflect the uncertainties in the CSI process, the Monte-Carlo Simulation (MCS) is conducted to explore the ranges of PLoT. By analyzing all the accumulated scores through the random sets, a spread of contaminant intrusion PLoT can then be identified in the network.

• Nutrition Research and Practice
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• 제3권3호
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• pp.226-233
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• 2009

Traditional nutrition education has not been shown to consistently produce behavior change. While it has been suggested that using emotion-based messages may be a better way to influence nutrition behavior change, this has not been well tested. Producing emotion-based messages is a multi-step process that begins with exploring subconscious barriers to behavior change rather than the more obvious and typically reported barriers. The purpose of this research was to uncover the emotional reasons, sometimes referred to as emotional pulse points, for mothers' choosing or not choosing to have more family meals. This would then serve as the first step to developing emotion-based messages promoting the benefits of family meals. Five focus group interviews were conducted with 51 low-income Black (n=28) and white (n=23) mothers. Metaphorical techniques were used to determine underlying feelings toward family and family meals. Discussions were video-taped, transcribed, and manually analyzed using a content-driven, immersion/crystallization approach to qualitative data analysis. Four themes emerged around the definition of family: acceptance, sharing, chaos, and protective/loyal. Some mothers felt mealtime was merely obligatory, and described it as stressful. Some reported a preference for attending to their own needs instead of sitting down with their children, while others felt that mealtime should be used to interact with and educate children and felt guilty when they were not able to provide family meals. Three themes emerged around feelings towards having or not having family meals: unimportant, important, and guilty. When explored further, mothers indicated that using the feeling of guilt to encourage family meals might be effective. Data obtained are being used to develop innovative, emotion-based messages that will be tested for effectiveness in promoting family meals.

• 건축역사연구
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• 제16권2호
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• pp.79-98
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• 2007

The building site was presumed as the Howonjeokwon or the Dasiwonji established at the traffic route among western inland areas in old Pyeonghaegun. The groundwork was composed inclination terrace of two steps. The upper step was the territory of the main house of ceremony symbolic+lodging function and the down step was divided in the territory of both Ikrang-chae of boarding and lodging management function and the territory of Haengrang-chae pavilion of rest reception management. The building composition by each territory formed space differentiation with the line of flow according to the thorough rule of court rank. The arrangement composition set the strong center axis in tandem, and it was the building arrangement interpreting the territory and the rule of court rank by function as the relationship of master and servant and was the building type emphasizing on the whole unity with the geometric symmetry structure. The Dasiwonji and the Hyeeumwonji had the common point which is the traffic architecture of semi governmental management reinforcing the boarding lodging function in the place which a visitor stayed. The Haeeumwonji and Dasiwonji had the difference in the size, but was the same in the composition system of construction. The external space and the system of the line of flow decided from the functional territory separation and the hierarchical rank as thorough as the geometric arrangement focusing on the whole unity. Namely, it was the strict and unusual system of the line of flow depended on the thorough rule of court rank than the efficient approach or arrangement of the line of flow. After being established to be the Howonjeokwon at the end of Koryeo, it disappeared at the time of the invasion of Japanese pirates when it was the time of the King Woo in Koryeo. It is presumed that it was continued until both wars, Imjin Byeongja, ago after changing its name to the Dasiwon, being restored to the small size at the end of Koryeo at the early of Choseon.

• Journal of Oral Medicine and Pain
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• 제30권3호
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• pp.301-317
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• 2005

전 세계적으로 구강암의 빈도는 점점 증가 추세이며, 특히 한국인의 있어 혀(tongue)는 구강암이 가장 호발하는 장소이다. 구강암은 발암 단계에서부터 과증식 병소(hyperplastic lesion), 이형성(dysplasia) 및 상피내암(carcinoma in situ) 을 거쳐 악성 암종으로 발전하는 다단계 발암과정을 보이며, 분자 생물학적 변이가 구강암을 진행시킴이 널리 알려져 있다. 또한, 구강암은 일반적으로 암세포의 증식 및 고사(apoptosis)의 억제가 중요한 역할을 하고 있다 알려져 있다. 그리고, Bcl-2 family 는 세포 고사에 주요한 역할을 하고 있음이 알려져 있다. 그러나, 이들과 관련한 구강암 발생과정의 변화에 대해서는 널리 연구된 바가 없다. 본 연구는 백서에서 발암 물질인 4-NQO로 구강암을 유도시키고, 구강암 발생 다단계별로 Bcl-2 family의 mRNA 변화를 RT-PCR을 이용해 살펴보았다. Bcl-2 family는 크게 3군, 즉 1) anti-apoptotic, 2) pro-apoptotic, 그리고 3) BH3 only protein으로 분류할 수 있으며, 본 연구에서 anti-apoptotic molecules인 Bcl-w는 모든 군에서 발현이 감소되었으며, Bcl-2는 발현이 증가 되었다. pro-apoptotic molecules에서는 Bad가 제 3군 (편평세포암종)에서 발현이 증가 되었고, 나머지는 감소하였다. BH-3 only protein에서는 Bmf가 제 2군에서, BBC3가 제 3군에서 발현이 증가하였고, 나머지는 모든 군에서 감소하였다. 결론적으로, 4-NQO로 유도된 백서의 발암단계에서, Bcl-2 family의 mRNA 양상은 다양하게 관찰되었으나, Bad 및 BBC3 mRNA가 제 3군에서, Bmf mRNA가 제 2군에서의 발현이 특별함을 알 수 있어, 다단계 발암과정에서의 구강암을 진단하는데 유용하리라 사료된다.

• 대한물리치료과학회지
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• 제15권2호
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• pp.87-95
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• 2008

Background: Hemiplegic patients usually have difficulty maintaining balance. Balance training is a major component of there habilitation program for patients with neurological impairment. The purpose of this study was to investigate the effects of PLS(Posterior Leaf Spring), FES(Functional Electrical stimulation), treadmill training, and neurodevelopmental treatment on the improvement of balance in patients with hemiplegia. Methods: We looked into published studies from Dankook University’s electronic library databases of RISS4U, KMbase, NCBI, and MEDLIS concerning the effectiveness of any form of intervention leading to improvement of balance. All types of studies relevant to the topic that were published in English during the time period of 1986 to 2005 were included. Results: 1. There were significant differences in standing balance, dynamic activity balance, and gait speed between barefoot subjects and subjects who wore SPAFO and HPAFO(p<.05). 2. The changes in ROM and FRT related to sex, age, height, and weight part of the diagnosis, as well as experience relapse, was of meaningless value. Changes in ROM related to the duration of pain and experiences of falling down were also meaningless. However, FRT showed significant static differences(p<.05). 3. The body-weight-support treadmill training scoring of standing balance, step length, and a timed 10m walking test showed definite improvement. 4. The proprioceptive control approach improved dynamic balance in patients with hemiplegia. Conclusion: Consequently, further study is needed to verify methods when physical therapists are researching balance ability in hemiplegic patient.

• 대한토목학회논문집
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• 제13권4호
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• pp.15-25
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• 1993

복합재료를 효과적으로 사용하기 위하여 복합재료 구조물의 설계기준 개발을 위한 연구가 진행되고 있다. 금속 셀의 좌굴에 대한 설계시에는 초기 결함의 영향과 탄성임계좌굴응력을 근거로 한 녹다운계수(Knock-down factor)를 정의하는 것이 중요한 과정이나 복합재료 쉘의 좌굴에 대한 설계시에는 초기 결함에 대한 민감도가 거의 연구되어 있지 않은 실정이다. 복합재료 쉘의 좌굴거동에 영향을 주는 설계변수는 많기 때문에, 쉘의 설계시 이 변수들로 인한 초기 결함 민감도를 분석하기 위하여 많은 실험을 필요로 하고 있으며 실험 이외의 다른 방법으로서는 이미 검증된 수치모델을 사용하는 것이다. 본 논문에서는 복합재료 쉘요소를 개발하는데 사용된 이론을 요약, 정리 하였으며 수치예제를 통하여 본 연구에서 제안한 쉘요소의 정확성을 검증하였다. 그리고 축방향으로 압축을 받는 GFRP 곡선형 판넬의 설계시 고려해야 하는 각 변수들을 다양하게 변화시키면서 좌굴거동에 미치는 영향을 유한요소 모델링에 의해 고찰하였다. 방법으로서 초기 결합 및 두께의 진폭을 고려한 비선형 해석과 고유치 해석을 수행하였으며 이 결과를 이용하여 녹다운 계수를 산출하였다.