• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.671-674
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• 2012

최근 스마트 기기가 발전함에 따라 가정 내에서 사용자의 편의성 추구를 위하여 다양한 서비스들이 제공되고 있다. 다양한 서비스들의 발달로 사용자들의 요구가 다변화 되며 요구의 정도 또한 전보다 한층 명확해지고 있다. 이러한 상황에서 사용자들의 N-Screen에 대한 요구도 다양하게 변모 되고 있으며, 그 흐름 또한 점차 진화해 나가는 실정이다. 기존의 N-Screen 시스템은 클라우드 서버로 해당 멀티미디어 콘텐츠를 모두 업로드 하여 비디오 스트리밍 방식을 사용하기 때문에 재생반응속도가 느리며, 서버의 성능에 따라 사용자수가 제한되는 문제가 발생한다. 또한 기존의 N-Screen 서비스는 웹 형태의 프로토콜을 사용하기 때문에 단방향 통신으로 수반되는 높은 지연과 오버 헤드 등의 여러 가지 문제들이 야기된다. 따라서 이러한 문제들을 해결하기 위하여 본 논문에서는 HTML5 기반의 Application을 제안한다. 제안된 시스템은 HTML5기반의 비디오 태그 (Video tag)와 프로그레시브 다운로드 (Progressive Download)를 지원하여 재생되는 멀티미디어 콘텐츠의 재생반응속도를 개선한다. 이는 비디오 스트리밍 방식에서 오는 고질적인 문제인 콘텐츠 재생반응속도와 비디오 스트리밍을 위한 콘텐츠 인코딩에서 오는 대규모 사용자의 접속제한을 해소할 수 있다. 또한 웹소켓을 통하여 기존의 N-Screen 시스템보다 낮은 지연과 양방향 소통으로 인하여 동적인 연결이 가능한 시스템을 제안한다.

• 한국잠사곤충학회지
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• 제53권1호
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• pp.1-5
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• 2015

갈색거저리의 산업 활용도가 높아짐에 따라, 효율적인 실내 대량사육 시스템의 확립이 더욱 중요하게 인식되고 있다. 본 연구는 대량사육을 위해 다양한 범위의 온도, 광주기, 사육밀도에서 갈색거저리의 생리적 특성을 알아보고자 수행되었다. 갈색거저리 알은 $17.5{\sim}27.5^{\circ}C$에서 70% 이상의 부화율을 나타냈고, 부화기간은 $25{\sim}35^{\circ}C$에서 5~7 일로 조사되었다. 결과적으로, 부화율과 산란 전 기간(egg periods)을 고려했을 때, 대량사육을 위해 적절한 실내온도는 $25{\sim}27.5^{\circ}C$였다. 다양한 온도 조건하에서 대량사육 시스템에서 유충의 발육기간은 개별사육 시스템에서 보다 더 짧았다. 번데기 무게는 $20^{\circ}C$와 $25^{\circ}C$를 제외한 대량사육 시스템에서 좀 더 높게 관찰되었다. 수요 탄력성과 생산중량을 고려했을 때, 가장 효과적인 조건은 $25^{\circ}C$에서 대량사육한 실험군이었다. 14L : 10D의 광주기 조건에서 157.35일로 가장 짧은 유충기간을 나타냈다.

• 동력기계공학회지
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• 제14권5호
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• pp.10-16
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• 2010

The main object of this study is to investigate the collection characteristics of multi-layer multi-stage porous plate system experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with the experimental parameters such as inlet velocity, tube diameter, inlet concentration, and stage number, etc. In results, the pressure drop becomes 22 to $115mmH_2O$ with increment of stage number (1 to 5) of porous plate system at tube velocity 15 m/s and tube diameter ${\Phi}8$. In case of fly ash and 5 stage, the collection efficiency becomes 90.5 to 95.7% increasing the tube velocity 12 to 15 m/s at inlet concentration $3g/m^3$ and tube diameter ${\Phi}8$. Additionally, it is estimated that the collection efficiencies of 5 stage are 94.3, 95.6 and 99.1% for fly ash, steel dust and based power, respectively (${\Phi}8$ tube, $V_t$ = 12m/s, inlet concentration $3g/m^3$).

• 천문학회보
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• 제38권2호
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• pp.71.1-71.1
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• 2013

Among quadruples or higher multiplicity stars, only a few binary systems have been discovered. They are important targets to understand the formation and evolution of multiple stellar systems because we can obtain accurate stellar parameters from photometric and spectroscopic studies. We present the observational results of this kind of rare object 1SWASP J093010.78+533859.5, for which the doubly eclipsing feature had been detected previously from the SuperWASP photometric archive. Individual PSF photometry for two objects with a separation of about 1.9 arcsec was performed for the first time in this study. Our time-series photometric data show that the brighter object A is an Algol-type detached eclipsing binary with an orbital period of 1.3 days and the fainter B is a W UMa-type contact eclipsing binary with a period of 0.23 days. Using the high-resolution optical spectra, we obtained well-defined radial velocity variations of the system A. Furthermore, stationary spectral lines were detected and should have originated from the other stellar component, which was confirmed by the third object contribution from the light curve analysis. No spectral feature of the system B was detected, probably due to its faintness. We obtained the binary parameters and the absolute dimensions from each light curve synthesis. The primary and secondary components of the system A have a spectral type of K1 and K5 main sequences, respectively. Two components of system B have nearly the same type of K3 main sequence. Light variations at out of eclipses were appeared in both systems, interpreting as the effect of stellar spots on these late spectral type stars. We estimated the distances to the systems A and B individually. They may have similar distances of about 70 pc and seem to be gravitationally bound with a separation of about 130 AU. In conclusion, we suggest that 1SWASP J093010.78+533859.5 is a quintuple stellar system with a hierarchical structure of a triple system A(ab)c and a binary system B(ab).

• 사상체질의학회지
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• 제24권3호
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• pp.34-41
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• 2012

Objectives In this study, we developed a mock-up of the system for Sasang Constitutional (SC) diagnosis. This system consists of 5 devices which are the face analyzer, the voice analyzer, the skin analyzer, the pulse analyzer, and the computer-based questionnaire. Our goal is to evaluate the repeatability of the system. Methods Each device is capable of classifying SC types. The classification probability of the integrated system for the SC types was obtained by summing the probability from each device. For evaluating the repeatability of the system, we collected data for 5 subjects, and repeated the measurement three times for each individual. The average and standard deviation were used for calculating the Coefficient of Variation. Results The results showed that the repeatability of the classification probability of the integrated system is about 8%, which implies the system is repeatable. Conclusions To increase usability of this system, it is desirable for the system to offer information on health condition of the user. The integrated constitutional diagnosis system will be upgraded to complement the convenience and to develop the diagnostic algorithm for the user's health condition.

• Journal of applied mathematics & informatics
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• 제29권5_6호
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• pp.1337-1349
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• 2011

So far as a solution of the given consistent linear system is concerned many numerical methods - both mathematically non-iterative as well as iterative - have been reported in the literature over the last couple of centuries. Most of these methods consider all the equations including linearly dependent ones in the system and obtain a solution whenever it exists. Since linearly dependent equations do not add any new information to a system concerning a solution we have proposed an algorithm that identifies them and prunes them in the process of solving the system. The pruning process does not involve row/column interchanges as in the case of Gauss reduction with partial/complete pivoting. We demonstrate here that the use of pruning as an inbuilt part of our solution process reduces computational and storage complexities and also computational error.

• Journal of Advanced Marine Engineering and Technology
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• 제34권5호
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• pp.695-702
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• 2010

Numerical analysis information will be very useful to improve fluid system. General information about an internal gas flow is presented by numerical analysis approach. Relating with hydrogen compressing system, which have an important role in hydrogen energy utilization, this should be a useful tool to observe the flow quickly and clearly. Flow characteristic analysis, including pressure and turbulence kinetic energy distribution of hydrogen gas coming to the cylinder of a reciprocating compressor are presented in this paper. Suction-passage model is designed based on real model of hydrogen compressor. Pressure boundary conditions are applied considering the real condition of operating system. The result shows pressure and turbulence kinetic energy are not distributed uniformly along the passage of the Hydrogen system. Path line or particles tracks help to demonstrate flow characteristics inside the passage. The existence of vortices and flow direction can be precisely predicted. Based on this result, the design improvement, such as reducing the varying flow parameters and flow reorientation should be done. Consequently, development of the better hydrogen compressing system will be achieved.

• Journal of Power Electronics
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• 제13권5호
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• pp.798-805
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• 2013

This paper presents the control and implementation of the dual-stator-winding induction generator for variable frequency AC (VFAC) generating system. This generator has two sets of stator windings embedded into the stator slots. The power winding produces the VFAC power to feed the loads, and the control winding is connected to the static excitation controller to control the generator for output voltage regulation with speed and load variations. On the basis of the idea of power balance, an instantaneous slip frequency control (ISFC) strategy using the information of both the output voltage and the output power is used in this system. A series of experiments is carried out on a 15 kW prototype for verification. Results show that the system has good static and dynamic performance in a wide speed range, which demonstrates that the ISFC strategy is suitable for this system.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.69-74
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• 2000

Linear and nonlinear motion responses of a Tension Leg Platform(TLP) was investigated by model tests. The model tests were carried out at KRISO's Ocean Engineering Basin which has a deep pit of which diameter and depth are 5 meters and 12.5 meters, respectively. Optical sensors were used for measuring drift motions, and a set of accelerometers were employed for analyzing wave frequency motions. ISSC TLP was chosen as the model for the present study. Scale ratio was 1/65 and elastic modelling of tether system were conducted. Very good agreement was obtained between experimental results and theoretical calculations not only in linear motion responses but tension responses, nonlinear wave drift force and double frequency excitations.

• 동력기계공학회지
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• 제17권2호
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• pp.87-94
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• 2013

Applicability of organic Rankine cycle for a passenger car with 3.5 L gasoline engine to convert low grade waste heat to useful shaft power has been numerically studied. Working fluid is R134a, and the Rankine cycle is composed of boiler for recovering engine cooling water heat, super heater for recovering exhaust gas heat, scroll expander for converting waste heat to shaft power, condenser for heat emission, internal heat exchanger, and feed pump. Assuming efficiencies of 90% for the heat exchangers, 75% for the scroll expander, and 80% for the feed pump, the Rankine cycle efficiency of 5.53% was calculated at the vehicle speed of 120 km/hr. Net expander shaft output after subtracting the power required to run the pump was 3.22 kW, which was equivalent to 12.1% improvement in fuel consumption. About the same level of improvement in the fuel consumption was obtained over the vehicle speed range of 60 km/hr~120 km/hr.