• Solar Energy
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• v.17 no.3
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• pp.3-11
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• 1997

Recently the construction of atrium buildings has increased but along with it many problems in thermal environment have arised. since the exterior wall of glass, indoor temperature is greatly influenced by weather conditions and since the space volume is very large, the vertical air temperature is not uniform. So, in this study, a Vertical Temperature Distribution Model was developed to predict the vertical air temperature of an atrium and evaluate the effects of the design parameters on the air temperature distribution of an atrium. To consider the characteristics of the vertical air temperature distribution in an atrium, the Satosh Togari's Macroscopic Model was used basically for the calculation of the vertical air temperature distribution in large space and the solar radiation analysis model and natural ventilation analysis model in atrium. And to calculate the unsteady-state inside wall surface temperature(boundary condition), the finite difference method was used. For the verification of the developed temperature distribution program, numerical evaluation of air flow by the ${\kappa}-{\varepsilon}$ turbulence model and in-situ test was conducted in parallel. The results of this study, the developed temperature distribution program was seen to predict the thermal condition of the atrium very accurately.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.286-288
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• 2007

In this paper, the fast locking PLL Frequency Synthesizer with low phase noise in a 0.18um CMOS process is presented. Its main application IS for the 915MHz ISM band wireless transponder upon the CPFSK (Continuous Phase Frequency Shift Keying) modulation scheme. Frequency synthesizer, which in this paper, is designed based on self-biased techniques and is independent with processing technology when damping factor and bandwidth fixed to most important parameters as operating frequency ratio, broad frequency range, and input phase offset cancellation. The proposed frequecy synthesizer, which is fully-integrated and is in 320M $^{\sim}$ 960MHz of the frequency range with 10MHz of frequency resolution. And its is implemented based on integer-N architecture. Its power consumption is 50mW at 1.8V of supply voltage and core area is $540{\mu}m$ ${\times}$ $450{\mu}m$. The measured phase noises are -117.92dBc/Hz at 10MHz offset, with low settling time less than $3.3{\mu}s$.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.74-80
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• 2004

Aspergillus fumigatus is one of the most common fungi in the human environment, both in-doors and out-doors. It is the main causative agent of invasive aspergillosis, a life-threatening mycosis among immunocompromised patients. The genome has been sequenced by an international consortium, including the Wellcome Trust Sanger Institute (U.K.) and The Institute for Genomic Research (TIGR, U.S.A.), and a ten times whole genome shotgun sequence assembly has been made publicly available. In this study, we identified tricarboxylic acid (TCA) cycle enzymes of A. fumigatus by comparative analysis with four other fungal species. The open reading frames showed high amino acid sequence similarity with the other fungal citric acid enzymes and well-conserved functional domains. All genes present in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans, and Neurospora crassa were also found in A. fumigatus. In addition, we identified four A. fumigatus genes coding for enzymes in the glyoxylate shunt, which may be required for fungal virulence. The architecture of multi-gene encoded enzymes, such as isocitrate dehydrogenase, 2-ketoglutarate, succinyl-CoA synthetase, and succinate dehydrogenase was well conserved in A. fumigatus. Furthermore, our results show that genes of A. fumigatus can be detected reliably using GlimmerM.

• Transactions of Materials Processing
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• v.22 no.4
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• pp.196-203
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• 2013

Flexible stretch forming is an appropriate process for manufacturing of components for aerospace, shipbuilding and architecture structures. Flexible stretch forming has several advantages including that it could be applied to form various shapes such as ones with double curved surfaces. In this study, a systematic numerical simulation was conducted for forming double curved surfaces using flexible stretch forming. The desired surface had a saddle type configuration. It had two radii one of 2500mm and the other of 2000mm along its length and width. In the simulation, the decrease of elastic recovery due to the stretching was confirmed. Experiments were also conducted to confirm the viability of the process. By comparing the simulation to the experiment results, the suitability of flexible stretch forming for double curved surfaces was verified. From the results, the maximum error from desired surface was confirmed at about 1.3mm at the edge of the surface. Hence, it is confirmed that flexible stretch forming has the capability and feasibility to manufacture curved surfaces for architectural skin-structures of buildings.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.152-161
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• 1996

In tis work, a three-stage pipelined A/D converter (ADC) was implemented to obtain 10-bit resolution at a conversion rate of 20 msamples/s for video applications. The ADC consists of three identical stages employing a mid-rise coding technique. The interstage errors such as offsets and clock feedthrough are digitally corrected in digitral logic by one overlapped bit between stages. The proposed ADC is optimized by adopting a unit-capacitor array architecture in the MDAC to improve the differential nonlinearity and the yield. Reduced power dissipation has been achieve dby using low-power latched comparators. The prototype was fabricated in a 0.8$\mu$m p-well CMOS technology. The ADC dissipates 160 mW at a 20 MHz clock rate with a 5 V single supply voltage and occupies a die area of 7 mm$^{2}$(2.7 mm $\times$ 2.6mm) including bonding pads and stand-alone internal bias circuit. The typical differential and integral nonlinarities of the prototype are less than $\pm$ 0.6 LSB and $\pm$ 1 LSB, respectively.

• Korean Journal of Computational Design and Engineering
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• v.7 no.1
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• pp.57-65
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• 2002

The purpose of this research is to develop a collaborative architectural design system. Design collaboration requires an extensive use of communication methods as well as the participation of various experts from different domains. Such facts address several issues when the Internet and digital media are able to create a completely new work environment. The building design process was studied, and possible modes of design collaboration were defined. A prototype system is being developed in accordance with the defined collaboration model. The system integrates a set of communication tools and web-based design media. Such media include a synchronous multi-user web CAD tool, a schematic 3D design tool, and a electronic whiteboard. A project database was designed in order to coordinate the project-wide communication which elaborates technologies such as web-based data access. In order to find out the effectiveness of the system, a usability test was performed both in quantitative and qualitative manner. The research will contribute to the development of world-wide design and construction collaboration through the Internet, which is becoming a mainstream building process model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1448-1453
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• 2015

In this paper, we propose an alternative method of communication to improve the reliability of in-vehicle networks by jointly using wireless communication networks. Wired Communication networks have been used in vehicles for the monitoring and the control of vehicle motion, however, the disconnection of wires or hardware fault of networks may cause a critical problem in vehicles. If the network manager detects a disconnection or faults in wired in-vehicle network like the Controller Area Network(CAN), it can redirect the communication path from the wired to the wireless communication like the Zigbee network. To show the validity and the effectiveness of the proposed in-vehicle network architecture, we implement the Electronic Stability Control(ESC) system as ECU-In-the-Loop Simulation(EILS) and verify that the control performance can be kept well even if some hardware faults like disconnection of wires occur.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.19-22
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• 2006

The CMD(Condition Monitoring & Diagnosis) System is used to monitor and analyze the PD(Partial Discharge), Arc, Temperature, Pressure, Gas in Oil and so on for reliability and availability of the substation. Although this system comes into the spotlight as the forecast and management of the failure and fault, there are some problems. For example, the unified standard was not defined, and the effective management of the layed communication network does not performed, limitation of physical space, etc. To resolve above problems, this paper suggests the IEC61850 compatible eCMD system architecture for monitoring and analyzing the CMD factor in substations. The suggested eCMD system consists of CMD-LU(Condition Monitoring & Diagnosis-Local Unit), IED(Intelligent Electronic Device), and engineering centers. The IEC61850 is the international standard that defines communication networks and system in substation.

• 한국IT서비스학회:학술대회논문집
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• 2006.11a
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• pp.177-184
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• 2006

시스템의 동적 요소를 기술하고 분석하기 위해 C&C view 아키텍처를 주로 사용하지만 시스템의 실행 순서나 상태에 대한 정보가 부족하기 때문에 단지 C&C view 아키텍처로만 시스템의 동적 요소를 분석하기가 어렵다. FSP model은 시스템의 동작을 표현하기 위한 모델링 언어로써 시스템의 동작을 모델링 할 뿐만 아니라 LTSA라는 FSP 검증 툴을 이용하여 시스템의 특성을 자동으로 파악하기에도 용이한 특성을 가지고 있어 시스템 동적 요소 분석에 도움을 준다. 하지만 관련 정보를 얻기 어려워 FSP model을 구현하는데 어려움이 있다. 이 논문은 C&C view 아키텍처와 요구 사항(Use Case Scenario 혹은 Sequence diagram)을 근간으로 시스템의 동적 요소를 FSP로 모델링 하는 방법을 정의한다. 또한 LTSA 툴을 이용하여 자동적으로 시스템의 특성을 검증할 수 있고, 이를 통해 시스템 구현 전에 시스템의 에러를 찾아내고 해결하는 도움을 줄 수 있다. C&C view 아키텍처는 시스템의 컴포넌트와 커넥터에 대한 정보를 제공하여 주고 요구 사항은 소프트웨어 시스템의 행동에 대한 정보를 제공하여 줄 수 있다. 만약 우리가 컴포넌트와 커넥터에 대한 정보가 있고 시스템 동적 요소에 대해 알고 있다면 우리는 이것을 기반으로 메시지 흐름도를 구현할 수 있다. 메시지 흐름도는 Harel, Kugler 와 Pnueli에 의해 개발된 Synthesized 알고리즘을 이용하여 Statechart로 만들어지고 이것은 바로 FSP model로 변환될 수 있다. 우리가 소프트웨어 시스템에 대한 FSP model을 가지고 있다면 이것을 기반으로 시스템 행동 특성을 체크할 수 있으며 이는 향후 발생할 수 있는 결함을 미리 찾아내는데 유용한 도움이 될 수 있다. 우리는 간단한 예제를 통해 본 논문의 이론을 수립하였으며 이를 기반으로 실제 어플리케이션에 적용하여 그 효용성을 검증하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.462-473
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• 2019

The effects of the location and dimension of the gate, location, and volume of the feeder, application of a chill, chill volume, and heating method of the feeder with respect to the effect of the mold-designing technologies on the defect status of the products are described. It is possible to increase the solidification time of the feeder by heating feeder. Furthermore, the pressure generated from the feeder is imposed on a product, and this decreases the generation of shrinkage porosities. In this study, two types of gating and feeding systems had been proposed: the bottom L-type junctions and the top L-type junctions. Additionally, solidification behaviors, such as solidification time, shrinkage porosities, weight percentage of chill system to product, hot spot, and solidification time ratio (=Solidification time of feeder/solidification time of product), are extensively analyzed by using commercial casting simulation software. Based on the solidification behaviors, reasonable mold design, feeding system, critical feeder heating temperature, and solidification time ratios are proposed in the sand casting process for the fabrication of carrier housing in order to reduce the casting defects and to increase the recovery rate.