• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권2호
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• pp.206-210
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• 2008

프로그레시브 스트리밍의 가장 큰 특징은 TCP를 통해 전송된 미디어 데이타가 수신 단말기로 다운로드 됨과 동시에 미디어의 재생이 실행되는 것이다. 프로그레시브 스트리밍에서는 TCP의 순서번호(sequence number)나 검사합(checksum) 기능 등을 통하여 손실된 패킷을 검출하여 재전송을 통해 복원이 가능하다. 그러나, 재전송에 소요되는 시간 동안 재생될 수 있는 충분한 량의 미디어 데이타가 수신 단말기 버퍼에 남아 있어야만 미디어의 끊김 없는 서비스가 가능하다. 본 논문에서는 이러한 끊김 없는 서비스가 가능하도록 수신 단말기의 버퍼 고갈 확률을 고려하여 실시간으로 초기 버퍼링 시간을 결정하는 방법을 제안하고 실험을 통해 제안된 방법의 효과를 검증한다.

• Journal of Nutrition and Health
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• 제32권7호
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• pp.767-774
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• 1999

This study was carrid out to examine a part of the mechanism for the etiology of diabetic complications. Thirty normal and forty streptozotocin(STZ)-induced diabetic rats were used as the animal models. Animals were sacrificed at the time points of 3 days, 1, 2, 4 and 6 weeks after STZ-injection and time course in body weight and organ weight, the levels of blood glucose, plasma lipid patterns, and atherogenic index were measured during 6 weeks. The STZ-diabetic animals showed 63% survival rate and fsting blood glucose levels of the diabetic animals measured in the range of 230-410mg/dL during the experimental period. The body weigh of diabetic animals decreased significantly throughout the experimental period and the relative weights of organs to body weight were significantly higher than the normal control ones. The enlargement of the kidney in the diabetic animals was especially remarkable. Plasma triglyceride concentration in diabetic rats substancially increased from the first week of onset of diabetes mellitus and maintained higher levels than the control ones throughout the whole experimental period. The plasma total cholesterol level and atherogenic index in the diabetic rats were significantly higher than the normal ones from the third day after STZ injection and showed a gradual increase with the duration of the disease. Throughout the experiment, the diabetic rats consistently showed a slightly lower HDL-cholesterol level compared to the normal animals. From the results of this study, it appears that the significant changes in blood lipid pattern in STZ-diabetic animals start from the first week after STZ injection.

• 한국컴퓨터산업학회논문지
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• 제3권9호
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• pp.1251-1260
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• 2002

실시간 응용 프로그램은 미디어 데이터간에 만족되어야 할 동기화 제약조건을 가지고 있다. 클라이언트의 버퍼를 버퍼레벨기법의 가상버퍼와 네트워크 상태를 포함한 피드백기법을 제안한다. 가변적 전송 지연 시간을 흡수하면서 피드백 제어에 의한 동기화를 수행한다. 버퍼의 수위가 정상레벨을 유지하는가에 대한 문제는 재생률과 QoS 서비스에 중요한 영향을 주게 된다. 본 논문에서는 이러한 문제를 해결하기 위해서 필터링함수, 제어함수, 네트워크 평가 함수 등을 적용하여 멀티미디어 서버에서 전송 시작시점을 결정하고 미디어의 재생 시 끊어짐이 없는 유연한 재생을 처리하게 된다. 주 미디어인 오디오 프레임이 상위임계레벨에 버퍼의 수위가 존재 할 경우는 점차적으로 재생시간을 줄이고, 오디오 프레임이 하위임계레벨에 버퍼의 수위가 있을 경우는 점차적으로 재생시간을 늘리는 시스템을 제안한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.282-285
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• 2006

This paper analyzed the characteristics of the Lossy JPEG of the meteorological satellite image, and analyzed the quality of the Lossy JPEG compression, which is proper for the LRIT(Low Rate Information Transmission) to be serviced to the SDUS(Small-scale Data Utilization Station) system of the COMS(Communication, Oceans, Meteorological Satellite). Since COMS is to start running after 2008, we collected the data of the MTSAT-1R(Multi-functional Transport Satellite -1R) for analysis, and after forming the original image to be used to LRIT by each channel and time zone of the satellite image data, we set the different quality with the Lossy JPEG compression, and compressed the original data. For the characteristic analysis of the Lossy JPEG, we measured PSNR(Peak Signal to Noise Rate), compression rate and the time spent in compression following each quality of Lossy JPEG compression. As a result of the analysis of the satellite image data of the MTSAT-1R, the ideal quality of the Lossy JPEG compression was found to be 90% in the VIS Channel, 85% in the IR1 Channel, 80% in the IR2 Channel, 90% in the IR3 Channel and 90% in the IR4 Channel.

• 산업경영시스템학회지
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• 제42권4호
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• pp.16-22
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• 2019

After Dantzig and Rasmer introduced Vehicle Routing Problem in 1959, this field has been studied with numerous approaches so far. Classical Vehicle Routing Problem can be described as a problem of multiple number of homogeneous vehicles sharing a same starting node and having their own routes to meet the needs of demand nodes. After satisfying all the needs, they go back to the starting node. In order to apply the real world problem, this problem had been developed with additional constraints and pick up & delivery model is one of them. To enhance the effectiveness of pick up & delivery, hub became a popular concept, which often helps reducing the overall cost and improving the quality of service. Lots of studies have suggested heuristic methods to realize this problem because it often becomes a NP-hard problem. However, because of this characteristic, there are not many studies solving this problem optimally. If the problem can be solved in polynomial time, optimal solution is the best option. Therefore, this study proposes a new mathematical model to solve this problem optimally, verified by a real world problem. The main improvements of this study compared to real world case are firstly, make drivers visit every nodes once except hub, secondly, make drivers visit every nodes at the right time, and thirdly, make drivers start and end their journey at their own homes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.202-205
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• 2005

The purpose of this work is to identify the characteristic of eye movement for visual training of the elderly. This investigation is to examine the relationship between the head and the eye motor system for the localization of visual target direction in three-dimensional space. All experiments were performed in a soundproof chamber. Twenty-one red LEDs (Light-Emitting Diode, Brightness: 20cd/$m^2$) arrayed in three lines on a half circle-surrounding panel are used. LEDs are horizontally 30 degree apart and vertically 20 degree apart from each other. The condition of stimulation is random and anti-saccade. Physiological parameter such as EOG (Electro-Oculography) was measured by BIOPAC system. We measure the mean latency time, which is the time from the start of visual stimulation to the response of the human body. The result shows that the mean latency time is short in the case of the condition of anti-saccade, the fixed head and a quarter visual stimulation. This finding can be used in developing programs for various visual improvements for the elderly by analyzing the characteristic of eye movement.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.399-404
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• 2001

In CNC machining, a 3D(3-dimension) linear segment and a 2D(2-dimension) circular arc are general forms given by CAD/CAM system. Generally, the 2D circular arc machining is processed using dividing into some linear segments. A 3D circular arc also don't exist in the standard form of NC data. This paper present a algorithm and method for real-time machining of a circular arc(not only the 2D one, but also the 3D one). The 3D circular arc machining is based on the 2D circular arc machining. It only needs making a new coordinate system, converting given 3D points(a start point, a end point, and a center point of a 3D circular arc) into points of the new coordinate system, and processing a inverse transformation about a interpolated point. The proposed algorithm was implemented and simulated on PC system. It was confirmed to give a gcod result.

• 대한후두음성언어의학회지
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• 제29권1호
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• pp.24-29
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• 2018

Background and Objectives : The purpose of this study was to evaluate the impact of surgical extent on voice using acoustic and aerodynamic measurements in a serially followed thyroidectomy patients. Materials and Method : From October 2015 to January 2017, 108 patients who had undergone thyroid surgery and voice test for preoperative, 2, 3, and 6 months postoperatively were classified into five operative types. The radiological stage preoperatively and histopathological stage postoperatively were classified according to the invasion of thyroid capsule and surrounding tissue. For each classification, the results of the voice analysis according to the period were compared and analyzed. Results : The difference of voice according to surgical extent, radiological stage, and histopathologic stage showed significant difference only with Maximal phonation time (MPT) over time. However, in the analysis of interaction between each classification and period, Phonation threshold pressure (PTP) only showed significant results. Conclusion : Differences in imaging and histopathologic stages have no significant effect on recovery of voice symptoms after thyroid surgery. As the extent of operation increases, the pressure to start vocalization is relatively higher, which also varies with time after surgery.

• Radiation Oncology Journal
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• 제29권4호
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• pp.277-282
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• 2011

Purpose: This study was performed to evaluate the change in the lumpectomy cavity volumes before and after whole breast radiation therapy (WBRT) and to identify factors associated with the change of volume. Materials and Methods: From September 2009 to April 2010, the computed tomography (CT) simulation data from 70 patients obtained before and after WBRT was evaluated. The lumpectomy cavity volumes were contoured based on surgical clips, seroma, and postoperative changes. Significant differences in the data from pre-WBRT CT and post-WBRT CT were assessed. Multiple variables were examined for correlation with volume reduction in the lumpectomy cavity. Results: The mean and median volume reduction in the lumpectomy cavity after WBRT were 17.6 $cm^3$ and 16.1 $cm^3$, respectively with the statistical significance (p < 0.001). The volume reduction in the lumpectomy cavity was inversely correlated with time from surgery to radiation therapy (R = 0.390). The presence of seroma was significantly associated with a volumetric change in the lumpectomy cavity after WBRT (p = 0.011). Conclusion: The volume of lumpectomy cavity reduced significantly after WBRT. As the time from surgery to the start ot WBRT increased, the volume reduction in the lumpectomy cavity during WBRT decreased. A strong correlation was observed between the presence of seroma and the reduced volume. To ensure appropriate coverage and to limit normal tissue exposure during boost irradiation in patients who has seroma at the time of starting WBRT, repeating CT simulation at boost planning is suggested.

• Wind and Structures
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• 제25권6호
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• pp.551-567
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• 2017

Studies of unsymmetrical blade H-Darrieus rotors at low wind speeds in terms of starting time, static torque, and power performances for different blade parameters: thickness-to-chord (t/c), camber position, and solidity are scarce. However these are required for knowing insights of rotor performances to obtain some design guidelines for the selection of these rotors. Here, an attempt is made to quantify the effects of these blade parameters on the performances of three different H-Darrieus rotors at various low wind streams. Different blade profiles, namely S815, EN0005 (both unsymmetrical), and NACA 0018 (symmetrical blade for comparison) are considered. The rotors are investigated rigorously in a centrifugal blower apparatus. Firstly the dynamic and static performances of the rotors are evaluated to determine the best performing rotor and their optimum solidity. Generalised performance equations are developed based on selected blade parameters which are validated for the unsymmetrical rotors. Further, the starting time is quantified with respect to the rotor inertia to determine the suitable range of inertia that helps the unsymmetrical blade rotor to self-start earlier than the symmetrical one. This study can work as a benchmark for the selection of optimum blade parameters while designing an unsymmetrical blade rotor at low wind speeds.