• 한국정보처리학회논문지
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• 제5권11호
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• pp.2954-2972
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• 1998

광대역 종합정보 통신망에서 주문형 비디오 서비스 등의 멀티미디어 서비스가 본격적으로 도입됨에 따라 압축된 비디오의 전송이 전체 통신망 트래픽의 상당 부분을 차지할 것으로 기대된다. 가변 비트율로 부호화된 비디오가 통계적 이득과 일정한 비디오 품질을 제공할 수 있는 장점 때문에 많이 사용이 될 것이다. 비디오 트래픽을 전송하기 위해서는 음성 및 데이터 보다 많은 대역폭을 요구하기 때문에 ATM 통신망에서의 적절한 자원 할당 기법의 설계를 위하여 비디오 소스의 특성화와 트래픽 모델링은 아주 중요하다. 그리고 셀 손실, 지연 및 지터 등과 같은 성능 척도를 분석하기 위하여도 적절한 통계적 소스 모델이 필요하다. 본 논문에서는 MPEG 비디오 소스에 대한 특성화와 트래픽 모델링에 대하여 분석 기술하였다. 모델들을 크게 두 가지 즉, 통계적 모델과 결정적 모델로 분류하였다. 통계적 모델에서는 AR(autoregnessive), Markov, Markov와 AR의 복합, TES, 그리고 자기유사 모델로 분류하였다. 결정적 모델에서는 $({\sigma},\;{\rho}$, 매개변수화된 모델, D-BND, Empirical Envelopes 모델로 분류하였다. 각 모델들에 대한 특성, 장점 및 단점을 분석하고, 각 모델의 복잡도에 대하여 비교 분석하였다.

• Journal of Power Electronics
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• 제15권3호
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• pp.753-762
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• 2015

This paper presents a nonlinear sliding mode control (SMC) scheme with a variable damping ratio for interior permanent magnet synchronous motors (IPMSMs). First, a nonlinear sliding surface whose parameters change continuously with time is designed. Actually, the proposed SMC has the ability to reduce the settling time without an overshoot by giving a low damping ratio at the initial time and a high damping ratio as the output reaches the desired setpoint. At the same time, it enables a fast convergence in finite time and eliminates the singularity problem with the upper bound of an uncertain term, which cannot be measured in practice, by using a simple adaptation law. To improve the efficiency of a system in the constant torque region, the control system incorporates the maximum torque per ampere (MTPA) algorithm. The stability of the nonlinear sliding surface is guaranteed by Lyapunov stability theory. Moreover, a simple sliding mode observer is used to estimate the load torque and system uncertainties. The effectiveness of the proposed nonlinear SMC scheme is verified using comparative experimental results of the linear SMC scheme when the speed reference and load torque change under system uncertainties. From these experimental results, the proposed nonlinear SMC method reveals a faster transient response, smaller steady-state speed error, and less sensitivity to system uncertainties than the linear SMC method.

• 대한구순구개열학회지
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• 제15권1호
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• pp.21-28
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• 2012

Unilateral cleft lip is not a simple and independent problem in all aspects. nasal deformity results from the cleft lip, maxillary hypoplasia, and abnormal muscular pull on the nasal structures, including abnormal muscular tension on the alar base and abnormal position of the orbicularis oris muscle. Its gross and histopathologic characteristics include widening of the alar base, a midline deviation of the columella and septum to the noncleft side, dorsal displacement of the dome, lateral rotation of medial crura, buckling of the alar cartilage, and underdevelopment of the pyriform aperture. Since Dr. Millard first presented his method for repair of the unilateral cleft lip and nasal deformity in 1955, no other technique has gained as much popularity as the rotation-advancement principle. Principles established more than 50 years ago and techniques are evolving continuously. Unlike earlier procedures, this repair gives the surgeon the opportunity to manipulate the individual cleft elements through various modifications while maintaining Millard's original surgical and anatomical goals. Although this strategy is applied worldwide, successful execution is variable and highly operator dependent. Millard and many other surgeons have made technical variations to adjust the procedure to each specific patient, to address some of its faults, and to gain new advantages. We will review the Mulliken's modifications that Dr. Millard made to his original rotation-advancement principle and inform cases applied modifying the rotation-advancement principle.

• 한국전자파학회논문지
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• 제20권2호
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• pp.167-173
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• 2009

본 논문에서는 단일 급전 능동 소자와 4개의 기생 소자로 구성된 5.8 GHz ISM 대역에서 동작하는 전자적인 빔 조향 배열 안테나를 제안하였다. 빔 조향은 고가의 위상 변위기를 이용하지 않고, 기생 소자의 부하에 연결된 가변 리액턴스 제어 회로의 리액턴스를 제어하여 얻을 수 있다. 제안한 안테나는 빔 조향 각도에 따라 ISM 대역 내에서 -10 dB 이하의 반사 손실을 가지면서도 E-평면과 H-평면으로 각각 ${\pm}30^{\circ}$의 빔 스캔을 실현하였다. 스캔 범위에서 이득은 E-평면에서 $6.18{\sim}7.53\;dBi$, H-평면에서 $7.022{\sim}7.779\;dBi$를 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제25권12호
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• pp.1734-1741
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• 2012

This trial was performed to study the effects of replacing soybean meal (SBM) with fermented rapeseed meal (RSM) on growth performance, serum biochemistry variable and intestinal morphology of broilers. A total of 640 d-old Arbor Acres broiler chicks were randomly allocated to 4 dietary treatments, 4 pens per treatment and 40 birds per pen for a 6-wk feeding trial. In the four treatment groups, fermented RSM replaced soybean meal at 0, 5, 10, and 15%, respectively. On 21 d and 42 d, two birds from each pen were randomly selected and slaughtered. Blood samples and sections of duodenum, jejunum, and ileum were collected for measurement of serum biochemical variables and intestinal morphology, respectively. Results showed that body weight gain (BWG) and feed conversion (FC) were significantly (p<0.01) poorer for birds fed the 15% fermented RSM diet than those fed with 0, 5 and 10% fermented RSM diets during all periods. Compared with 0 and 5% fermented RSM groups, IgG content in the serum of birds in 10 and 15% fermented RSM groups was improved (p<0.01) urea nitrogen content of serum was reduced (p<0.01) during both growing and finishing periods. However, IgM, phosphorus and calcium levels increased (p<0.05) only during the growing period. Increased (p<0.05) villus height was observed in the duodenum and jejunum of broilers fed the diet with 10% fermented RSM. In addition, villus height to crypt depth ratio in the jejunum was significantly higher (p<0.01) for birds fed the diet with 10% fermented RSM than for those fed diets with 0, 5 and 15% fermented RSM. The present results suggest that RSM fermented with Lactobacillus fermentum and Bacillus subtilis is a promising alternative protein source and that it could be safely used replace up to 10% SBM in broiler diets.

• 가정과삶의질연구
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• 제23권5호
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• pp.133-143
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• 2005

The purpose of this study was to gain understanding about residential satisfaction and preference of the members of the future elderly generation who have an intention to develop senior congregate housing. The data for this study were collected from 600 participants who were in their 40s to 60s, residing in Seoul, and who have an intention to develop senior congregate housing. The data collection spanned from December 1st to 20th, 2004. The results of this study were as follows: Firstly, the respondents who had a higher level of education, higher income, and a high-ranking job showed relatively higher residential satisfaction with their present house. Similar satisfaction level came between their present house and expecting ones in their later life. Financial responsibility was the most serious expected problem when they continue living in the present house in the later life. It means that the economic ability is the primary factor that determines whether they will have a stable life later. Secondly, as for the preference for the senior housing developer type, the group who preferred collectively developed senior congregate housing far outnumbered the other who preferred independent developer type. Also, the group who preferred collective developer type had higher economic ability than that of the other. These results indicate that above all, economic competence is the must significant variable, which should be considered in the future life and residential planning for the elderly. Korean senior congregate housing models should be developed based upon elaborate research. It is also necessary to develop different types of housing, such as a more practical type and a high quality type, as well as to respond to different kinds of developmental objectives, such as marketability and public benefit.

• 한국의류산업학회지
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• 제9권1호
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• pp.6-14
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• 2007

The purpose of this study was to delve into what type of expression mode of fashion design could suit the life style of digital nomads, as the appearance of nomadic life style was concurrent with people's modified way of thinking and sociocultural changes in today's digital society. It's basically meant to define the roles of fashion design, which was discussed as a way of improving the quality of life as a sort of 'culture,' and to suggest some of the right directions for fashion design in the future. The culture of today's digital era is marked by a pursuit of high mobility and high speed, and by nomadic disposition that is built on flexible thinking. The kind of design that lets people carry nomadic things with them and thereby improve their mobility can satisfy their needs for mobility, and body-friendly design that functions as a device of information in itself can meet their needs for mobility as well. The leading example of the latter is a wearable computer, and wearable scientific technology will be taken to another level, thanks to the advance in digital technology. In the future, that will be more accessible to people in general, and subminiature digital equipment will gain popularity in fashion industry as part of textiles and clothing or as an accessory. And specific kinds of design will be widespread, including variable design, multi-functional design and modular design. The first serves as a tool to protect the human body and to facilitate the adaptability of it to the given circumstances, and the second is characterized by a superb physical and psychological protectability. The third lets wearers bring design to completion at their own option, owing to an increase in the number of open-minded people and the development of interactive media. All these types of design could be called a wearer-friendly, human-oriented design that is specifically appropriate for the digital age. Wearers can actively be involved in design process as productive consumers, which is expected to help increase opener practices in fashion design sector.

• 대한기계학회논문집A
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• 제33권6호
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• pp.607-613
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• 2009

In this paper, we made a simple paper feeding system which is one of MTS (media transport system) and controllers. The plant has a flexible paper and two driving rollers and two driven rollers. The control system has two conventional PID controllers. Skew angle and feeding speed of MTS deteriorate the quality of feeding system. In order to control a feeding speed and skew of feeding paper, we control rotational velocity of two driving rollers. Therefore, this controller has two inputs and two outputs as MIMO (multi-input and multi-output) system. The control inputs were the feeding speed and the skew displacement of the paper. The control outputs were the rotational velocity to each driving roller. To find appropriate PID gains of two controllers, we proposed an optimization technique. We assume the system variables and performance of a whole system as follows. PID gains of two controllers for skew and feeding speed are system variables. System performance is both skew and feeding speed. We simulates to making mathematical correlation using global Kriging interpolation. To find appropriate value of system variables, optimization method is simulation in sequence as following method. First, the optimization solver simulates with DOE (design of experiment) tables to find correlation equation of both system variable and performances. Then, the solver guesses the appropriate values and simulates if the system variables are appropriate or not. If the result of validation doesn't satisfy the convergence and iteration tolerance, the solver makes a new Kriging models and iterates this sequence until satisfy the tolerances.

• 인터넷정보학회논문지
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• 제21권3호
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• pp.11-19
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• 2020

본 논문에서는 TEA, XTEA 및 XXTEA 암호 알고리즘을 통합한 병합 TEA 블록 암호 프로세서를 설계한다. TEA 암호 알고리즘이 처음 설계된 이후, 보안 결함을 보완하기 위해 XTEA와 XXTEA 암호 알고리즘이 설계되었다. 3가지 유형의 암호 알고리즘은 128비트의 매스터 키를 사용하며, 설계된 암호 프로세서는 TEA와 XTEA 암호 알고리즘은 64비트 단위로, XXTEA 암호 알고리즘은 32비트의 배수로 최대 256비트까지 가변 길이 메시지 블록에 대한 암·복호화를 수행하도록 구현하였다. 64비트 메시지 블록에 대한 최대 처리율은 137Mbps이며, 256비트 메시지에 대한 최대 처리율은 369Mbps이다. 본 논문에서 설계된 병합 TEA 블록 암호 IP는 경량 암호인 LEA 암호와 비교하여 면적 측면에서는 16%의 이득이 있다. 본 논문에서 설계된 암호 프로세서 IP는 스마트 카드, 인터넷뱅킹, 전자상거래 등과 같은 모바일 분야의 보안 모듈로 응용이 가능할 것으로 사료된다.

• Journal of Power Electronics
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• 제14권2호
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• pp.271-281
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• 2014

Fluctuating wind conditions necessitate the use of a variable speed wind turbine (VSWT) with a AC/DC/AC converter scheme in order to harvest the maximum power from the wind and to decouple the synchronous generator voltage and frequency from the grid voltage and frequency. In this paper, a combination of a three phase diode bridge rectifier (DBR) and a modified topology of the diode clamped multilevel inverter (DCMLI) has been considered as an AC/DC/AC converter. A control strategy has been proposed for the DCMLI to achieve the objective of grid interface of a wind power system together with local load compensation. A novel fixed frequency current control method is proposed for the DCMLI based on the level shifted multi carrier PWM for achieving the required control objectives with equal and uniform switching frequency operation for better control and thermal management with the modified DCMLI. The condition of the controller gain is derived to ensure the operation of the DCMLI at the fixed frequency of the carrier. The converter current injected into the distribution grid is controlled in accordance with the wind power availability. In addition, load compensation is performed as an added facility in order to free the source currents being fed from the grid of harmonic distortion, unbalance and a low power factor even though the load may be unbalanced, non-linear and of a poor power factor. The results are validated using PSCAD/EMTDC simulation studies.