• 한국철도학회논문집
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• 제8권4호
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• pp.314-320
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• 2005

This paper is designed to help train dispatcher resolve railway conflicts in rent-time. We developed a mixed integer programming model to optimize the train schedule that determines the best overtaking or crossing positions, The objective of the model is to minimize the maximum lateness of the trains and reduce the total sum of the lateness, while satisfying the field constraints associated with the difference between passenger trains and freight trains, and the limited number of sidings. We applied the model on a portion of a single line track, Joong-Ang Line to ascertain the efficiency of the model, and showed how the model can be used to resolve the railway conflicts. The results indicates that our model can provide useful results in terms of optimal schedule for the test problem. This type of modeling approach would be useful for a train dispatcher to make a real-time railway conflict resolution.

• 전력전자학회논문지
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• 제5권5호
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• pp.508-514
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• 2000

본 논문에서는 역률개선용 단일 스위치 부스트 플라이백 결합형 ZCS quasi-resonant converter(QRC)를 제안한다. 제안된 컨버터는 입력전류를 불연속 모드로 동작시켜 역률을 개선하며 입력전류의 zero-crossing-point에서의 왜곡을 개선함으로써 고조파를 감소시켜 역률을 향상시켰으며 좋은 출력전압의 regulation 성능을 가지고 있다. 그리고 체계적인 설계를 위하여 설계식을 제안하였으며 제안된 설계식을 통하여 프로토타입 컨버터를 설계하였다. 실험결과 효율은 약 86%, 역률은 약 0.985이상을 얻었다. 따라서 본 컨버터는 스위칭 주파수가 수백kHz이상이고 높은 regulation성능을 요구하는 낮은 전압의 소용량 컨버터에 적합하다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.727-729
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• 2002

In this paper, we proposed quad variable rates ADPCM coding method and its implementation on C6000 DSP, which is modified from the standard ADPCM of ITU G.726 for speech quality improvement considering the environmental noise Four coding rates, 16Kbps, 24Kbps, 32Kbps and 40Kbps are used for speech window samples and the rate decision threshold is decided by the environmental noise level. The object of the proposed method is to reduce the coding rate while retaining the speech quality and the speech quality is considerably close to 40Kbps single rate coder with the coding rate close to 16Kbps single rate coder under the environmental noise. The environmental noise level affects the coding rate and the noise level is calculated per every speech window samples. At high noise level, more samples are coded at higher rates to enhance the quality, but at low noise level, only the big speech signals are coded at higher rates and more speech samples are coded at lower coding rates to reduce the coding rates. The influence of the noise on tile speech signal is considerably high for small signals and the small signal has the higher ZCR (zero crossing rate). The method is simulated in PC and to be implemented on C6000 floating point DSP board in real time operations.

• 한국공간구조학회논문집
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• 제1권1호
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• pp.117-124
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• 2001

In Single-layer latticed domes with rectangular network which is composed of ring of circumferential direction and rafter of longitudinal direction, that is, rib domes, if we use the cross-membered junction's method for the advantage in fabrication and construction, the eccentricity is occurred in the nodal point of crossing members. This paper is aimed at investigating the buckling characteristics for the effect of eccentricity according to rise-span ratios and distance of eccentricity. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems. The conclusion were given as follows: 1. The maximum decreasing ratio of buckling strength due to the junction's eccentricity is about 60% in models of this paper. 2. In the increasing ratio of buckling strength for rise-span ratio, that of Type 3 models is larger than that of type 2 models. On the other hand, that of Type 2 mode is larger than that of Type 3 for eccentricity-distance. 3. In the viewpoint of the value of buckling strength, that of Type 2 models is larger than that of type 3 models. The effect of the junction's rigidity on buckling strength is not great for overall models. Therefore if we use the cross-membered junction's method for the advantage in fabrication and construction, the method of Type 2 will have the great advantage of that of Type 3.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.325-333
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• 2003

An analysis of the electronic structure and bonding in the ternary silicide YNiSi₃is made, using extended Huckel tight-binding calculations. The YNiSi₃structure consists of Ni-capped Si₂dimer layers and Si zigzag chains. Significant bonding interactions are present between the silicon atoms in the structure. The oxidation state formalism of $(Y^{3+})(Ni^0)(Si^3)^{3-}$ for YNiSi₃constitutes a good starting point to describe its electronic structure. Si atoms receive electrons from the most electropositive Y in YNiSi₃, and Ni 3d and Si 3p states dominate below the Fermi level. There is an interesting electron balance between the two Si and Ni sublattices. Since the ${\pi}^*$ orbitals in the Si chain and the Ni d and s block levels are almost completely occupied, the charge balance for YNiSi₃can be rewritten as $(Y^{3+})(Ni^{2-})(Si^{2-})(Si-Si)^+$, making the Si₂layers oxidized. These results suggest that the Si zigzag chain contains single bonds and the Si₂double layer possesses single bonds within a dimer with a partial double bond character. Strong Si-Si and Ni-Si bonding interactions are important for giving stability to the structure, while essentially no metal-metal bonding exists at all. The 2D metallic behavior of this compound is due to the Si-Si interaction leading to dispersion of the several Si₂π bands crossing the Fermi level in the plane perpendicular to the crystallographic b axis.

• 한국응용곤충학회지
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• 제36권1호
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• pp.96-104
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• 1997

DNA 다형성을 이용한 누에 유전자 해석기술을 개발하기 위하여 광식성 누에 계통 J111과 비광식성계통 $C_3$의 DNA를 분리하여 유전자 은행을 제작하였다. 누에 유전자 은행은 genomic DNA를 EcoRI로 절단한후 pUC18에 ligation 시켜 DH5$\alpha$ E. coli에 형질전환 시켰다. 형질전환 후 얻어진 colony는 15개 누에 품종의 genomic DNA에 hybridization하였을 때 누에의 품종에 관계없이 highly repetitive, moderately repetitive 및 single 혹은 low copy number 로 구분되었다. RFLP마커에 적합한 single 및 low-copy number band만을 형성하는 colony probe을 신속하게 선발하고자 colony또는 genomic DNA로 hybridization하였다. Single 및 low-copy number의 특성을 가진 219개의 clone을 선발하여 Hind III등 8종의 제한효소별로 처리한 genomic DNA를 이용하여 다형성을 검정하여 J111과 $C_3$ 계통간 다형성을 보인 46개의 clone을 선발하였다. 선발된 clone의 일부를 J111과 $C_3$를 교배하여 얻은 $F_2$의 blot에 hybridization 결과 RFLP clone들이 양친검정에 이용가능하여 누에 RFLP 연관 지도 작성의 기반을 조성하게 되었다.

• 한국산림과학회지
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• 제46권1호
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• pp.53-56
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• 1980

무궁화의 종내(終內) 일대잡종(一代雜種)에서 화색(花色)과 화형(花型)의 분리현상(分離現象)을 조사(調査)할 목적(目的)으로 품종간(品種間) 교배(交配)를 하여 다음과 같은 결과(結果)를 얻었다. 1. 화판(花瓣)의 자주색(紫朱色)은 백색(白色)에 대(對)하여 dominance하고 세포질(細胞質) 유전(遺傳)에 의(依)한 것이라 추측(推測)된다. 2. 화판(花瓣)의 홑과 겹은 Ss, dd인자(因子)에 의(依)하여 발생(發生)한다. 3. 배수체(倍數体)무궁화와의 $F_1$의 화색(花色) 화형(花型)에는 큰 변화(變化)가 없었다. 4. Open-pollination되어 얻은 $F_1$에서 화색(花色)에 많은 변이(變異)가 있었다. 5. 유색(有色)견 화판(花瓣)무궁화와의 $F_1$에서는 화판(花瓣)에 적색(赤色) 반문(斑紋)이 있는 변이개체(變異個体)가 다수(多數) 발생(發生)되었다.

• 대기
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• 제17권4호
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• pp.381-391
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• 2007

The characteristics of flow around a single obstacle with fixed height and varied length and width are numerically investigated using a computational fluid dynamics (CFD) model. As the obstacle length increases, flow distortion near the upwind side of the obstacle increases and the size of the recirculation zone behind the obstacle also increases. As the obstacle width increases, the size of the recirculation zone decreases, despite almost invariable flow distortion near the upwind side of the obstacle. Flow passing through an obstacle is separated, one part going around the obstacle and the other crossing over the obstacle. The size of the recirculation zone is determined by the distance between the obstacle and the point (reattachment point) at which both the flows converge. When the obstacle width is relatively large, flows are reattached at the obstacle surface and their recoveries occur. Resultant shortening of the paths of flows crossing over and going around decreases the size of the recirculation zone. To support this, the extent of flow distortion defined based on the change in wind direction is analyzed. The result shows that flow distortion is largest near the ground surface and decreases with height. An increase in obstacle length increases the frontal area fraction of flow distortion around the obstacle. In the cases of increasing the width, the frontal area fraction near the upwind side of the obstacle does not change much, but near the downwind side, it becomes larger as the width increases. The frontal area fraction is in a better correlation with the size of the recirculation zone than the building aspect ratios, suggesting that the frontal area fraction is a good indicator for explaining the variation in the size of the recirculation zone with the building aspect ratios.

• 대한의용생체공학회:의공학회지
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• 제38권1호
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• pp.32-42
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• 2017

The aim of this study was to evaluate driving performance of Healthy and disabled groups (with or without driver's license) to control steering wheel by using steering assistive devices in the driving simulator. The persons with partial loss of use of all four limbs have problems in operation of the motor vehicle because of functional loss to operate steering wheel. Therefore, if steering assistive devices for grasping the steering wheel are used to control the vehicle on the road in persons with disabilities, the disabled persons can improve mobility in their community life by driving a motor vehicle safely. Ten healthy subjects (with or w/o driver's license) and ten subjects with physical disabilities (with or w/o driver's license) were involved in this study to evaluate driving performance to operate steering wheel by using four types of steering assistive devices (Single-pin, V-grip, Palm-grip, Tri-pin) in driving simulator. STISim Drive 3 software was used to test the steering performance in four scenarios: straight road at low and high speed of vehicle (40 km/h and 80 km/h), curved road at low and high speed of vehicle (40 km/h and 80 km/h). This study used two-way ANOVA in order to compare the effects of two factors (type of steering assistive device and subject group) in the three dependent variables of driving performance (the lateral position of vehicle, standard deviation of lateral position representing the variation of the left and right movement of the vehicle and the number of line crossing). The mean values of the three dependent variables (lateral position, standard deviation of lateral position, the number of line crossing) of steering performance were statistically significantly smaller for the healthy or disabled groups with driver's license than the other groups without driver's license on the curved road at high speed of vehicle compared to low speed of vehicle.

• 전자공학회논문지SC
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• 제48권5호
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• pp.31-36
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• 2011

본 논문에서는 Mel-Frequency Cepstral Coefficient (MFCC), Decorrelated Filter Bank (DFB), Octave-based Spectral Contrast (OSC), Zero-Crossing Rate (ZCR), 그리고 Spectral Contract/Roll-Off를 복합 특징벡터로 결합하여 Support Vector Machine (SVM)을 이용한 음악 장르 분류 시스템을 설계하였다. 기존 방식에서는 전체 학습 데이터에 대한 특징벡터를 정규화를 한 후 SVM 모델을 생성하여 분류를 시행하였다. 본 논문에서는 비교 대상이 되는 한 쌍의 클래스에 대해서 One-Against-One (OAO) SVM으로 모델을 생성할 때 선택된 두 클래스의 특징벡터에 대해서만 정규화를 시행하는 방식을 제안한다. 기존 정규화 방식을 이용하면 단일 특징벡터로 OSC를 사용할 경우에는 60.8%, 복합 특징벡터를 모두 이용하는 경우에는 77.4%의 인식율을 얻을 수 있었다. 또한, 제안된 정규화 방식을 이용하면 OSC와 복합 특징벡터에 대해서 각각 8.2%와 3.3%의 추가적인 성능 향상을 얻을 수 있었다.