• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.4
• /
• pp.627-631
• /
• 2009

As renewable and sustainable energy, solar energy and wind energy have advantages in reducing the pollution sources. The paper presents a hybrid system which includes the solar cell and the wind generator. HOMER provides a platform to design and simulate the power system and then to choose the optimization results. This paper simulates with the HOMER and performs a pre-feasibility study of stand-alone hybrid energy systems for applications in a lab.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2013.11a
• /
• pp.227-229
• /
• 2013

본 논문은 최근 연구가 지속적으로 진행되고 있는 움직임 추정 기술 중 하나인 1비트 변환(One-bit Transform, IBT) 알고리듬의 정확도를 개선시킨 알고리듬을 제안하였다. 1비트 변환 알고리듬은 정합오차 기준을 기존의 Sum of Absolute Differences (SAI)에서 이진연산이 가능한 정합오차로 바꿔서 하드웨어 설계에 보다 적합하도록 제안된 알고리듬이지만 정합 과정에서 많은 오차를 야기하는 단점을 가지고 있다. 본 논문에서는 1비트 변환 알고리듬 과정 중 계산 되는 필터 값의 보정을 통해 움직임 추정의 정확도를 향상 시켰다. 실험 결과에서 제안된 알고리듬이 객관적인 화질 측면에서 기존의 1비트 변환 알고리듬보다 더 우수한 성능을 보이는 것을 확인할 수 있었다.

• Kyungpook Mathematical Journal
• /
• v.54 no.2
• /
• pp.173-188
• /
• 2014

In this paper, a new class of open sets, namely ${\gamma}^*$-pre-open sets was introduced and its basic properties were studied. Moreover a new type of topology ${\tau}_{{\gamma}p^*}$ was generated using ${\gamma}^*$-pre-open sets and characterized the resultant topological space (X, ${\tau}_{{\gamma}p^*}$) as ${\gamma}^*$-pre-$T_{\frac{1}{2}}$ space.

• Journal of the Korean housing association
• /
• v.22 no.1
• /
• pp.115-122
• /
• 2011

This study aimed at quantifying the impact of envelope insulation on energy consumption for thermal controls in residential buildings in southern part of Korea. A series of parametric simulations for a range of R-values of walls, roof, floor, and windows were computationally conducted for a prototypical Korean detached house. Analysis revealed that the total amount of heat gain was larger than that of heat loss, while the amount of energy for cooling was smaller than that for heating due to the difference of system efficiency; the envelope heat transfer was more significant for the heat loss, thus, the increase of the envelope insulation was more effective to reduce heating load; and there were certain levels of envelope insulation after which the energy saving effect was not significant. These findings are expected to be a fundamental database for the decision of proper insulation level in Korean residential buildings.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.03b
• /
• pp.9-9
• /
• 2010

The proton exchange membrane fuel cell (PEMFC) holds great promise of clean power. However, in practical applications which use the PEMFC as the power source, the output voltage from the fuel cell undergoes transient response especially during acceleration and deceleration. This paper presents the relationships between the internal voltage drop, voltage of time constant, time constant of FC1 and FC2 (in series and in parallel) charge curves and discharge curves respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.203-203
• /
• 2010

The proton exchange membrane fuel cell (PEMFC) is different from the normal power supply, and it is a nonlinear, multi-input, strong coupling, the complex dynamic system with large time delay. At present, many studies on the content of the fuel cell fuel cells focus on a static process, this paper analyzed in subsequent sections of the process of fuel cell dynamic response time of transition, and then it found the method to reduce the response time during the process of load change to ensure that the stability of output power.

• Proceedings of the KIEE Conference
• /
• 2009.04a
• /
• pp.177-179
• /
• 2009

Solar, as an ideal renewable energy, it has inexhaustible, clean and safe characteristics. However, solar energy is an extreme intermittent and inconstant energy source. In order to improve the photovoltaic system efficiency and utilize the solar energy more fully, and the DC current varies with the irradiation, it is necessary to study the characteristics of photovoltaic I-V according to the external factors. This paper presents the analysis of characteristics of photovoltaic I-V according to the irradiation.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.2
• /
• pp.62-66
• /
• 1996

Since 1980, Korea Research Institute of Standards and Science (KRISS) have performed 8 round robin tests in gauge block measurement in order to evaluate the measurement capability and the state of environment control of National Calibration and Test Institutions. Two sets of five gauge blocks (nominal size : 1, 3, 10, 25, 100 mm) having different thermal expansion coefficients for each set were circulated for the measurement, and the measurement results were collected and analyzed to evaluate the traceability to the standard of KRISS. The method and results of the test are presented.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.371-375
• /
• 2009

The distribution control of refrigerant flow is one of the basic technique to enhance system efficiency. However, if engineers forget to control the refrigerant flow speed in all operation range, refrigerant flow mal distribution becomes a noise source. The refrigerant flow noise should be checked and controlled at the lowest air flow mode which is the most silent mode and frequently used in night time.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.376-380
• /
• 2009

The transmission noise characteristics through the ventilating duct was conducted numerically using SYSNOISE. A ventilating system is usually composed of mufflers for preventing noise transmission from the ventilator into indoors through the ducts and distributors for transferring air to or from each room. The transmitted noise characteristics of distributors which have different branch angles and of mufflers having different shapes were analyzed numerically. New duct element combining a muffler and a T-shaped distributor was developed for better noise reduction in this paper. New element's performance was shown numerically.