• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.927-930
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• 2003

In this paper, a design of processor IP for TCP/IP protocol stack is described. The processor consists of input and output buffer memory with dual bank structure, 32-bit RISC microprocessor core, DMA unit with on-the-fly checksum capability. To handle the various modes of TCP/IP protocol, hardware and software co-design approach is used rather than the conventional state machine based design. To eliminate delay time due to the data transfer and checksum operation, DAM module which can execute the checksum operation on-the-fly along with data transfer operation is adopted. By programming the on-chip code ROM of RISC processor differently. the designed stack processor can support the packet format conversion operations required in the various TCP/IP protocols.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2629-2650
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• 2019

It is important to construct fully homomorphic encryption with ciphertext matrix that makes fully homomorphic encryption become very nature and simple. We present a general design method of constructing fully homomorphic encryption whose ciphertext is matrix. By using this design method, we can deduce a fully homomorphic encryption scheme step by step based on a basic encryption scheme. The process of deduction is similar to solving equation and the final output result is a fully homomorphic encryption scheme with ciphertext matrix. The idea of constructing ciphertext matrix is ciphertexts stack, which don't simply stack ciphertexts together but is to obtain the desired homomorphic property. We use decryption structure as tool to analyze homomorphic property and noise growth during homomorphic evaluation. By using this design method, we obtain three corresponding fully homomorphic encryption schemes. Our obtained fully homomorphic encryption schemes are more efficient. Finally, we introduce the adversary advantage and improve the previous method of estimating concert parameters of fully homomorphic encryption. We give the concert parameters of these schemes.

• 신재생에너지
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• 제1권4호
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• pp.49-54
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• 2005

There is close relation between the heat generation in the fuel cell stack and the fuel performance. In PEM fuel cell vehicles, the stack coolant temperature is about $65^{\circ}C$, which is far lower than that for general automobile engine. Therefore, it is hard to release heat generated in the stack by using a radiator of limited size because of the reduced temperature difference between the coolant and the ambient air. In this study, indirect stack cooling system using $CO_2$ heat pump was designed and its stack cooling performance in releasing heat to the ambient was investigated. This work focuses on a series of processes that grasp the relation among the fuel cell power, the radiator capacity and the stack temperature. The purpose of this work is to find out a way to properly release sufficient amount of heat through the finite sized radiator, so that the slack power generation can not be deteriorated due to the stack temperature increase. The optimization between the compressor power consumption and the fuel cell output power can be carried out to maximize the performance of fuel cell system.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.465-477
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• 2023

In proton exchange membrane fuel cell (PEMFC), proper thermal management of the stack and moisture generation by electrochemical reactions significantly affect fuel cell performance. In this study, the PEMFC dynamic characteristic model was developed through Simcenter AMESim, a development program. In addition, the developed model aims to understand the thermal resin balance of the stack and performance characteristics for input loads. The developed model applies the thermal management model of the stack and the moisture content and permeability model to simulate voltage loss and stack thermal behavior precisely. This study extended the C based AMESet (adaptive modeling environment submodeling tool) to simulate electrochemical reactions inside the stack. Fuel cell model of AMESet was liberalized with AMESim and then integrated with the balance of plant (BOP) model and analyzed. And It is intended to be used in component design through BOP analysis. The resistance loss of the stack and thermal behavior characteristics were predicted, and the impact of stack performance and efficiency was evaluated.

• 디지털산업정보학회논문지
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• 제11권3호
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• pp.1-9
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• 2015

In this paper, we implemented the computer vision platform design with MEAN Stack through Raspberry PI 2 model which is an open source platform. we experimented the face recognition, temperature and humidity sensor data logging with WiFi communication under Raspberry Pi 2 model. Especially we directly made the shape of platform with 3D printing design. In this paper, we used the face recognition algorithm with OpenCV software through haarcascade feature extraction machine learning algorithm, and extended the functionality of wireless communication function ability with Bluetooth technology for the purpose of making Android Mobile devices interface. And therefore we implemented the functions of the vision platform for identifying the face recognition characteristics of scanning with PI camera with gathering the temperature and humidity sensor data under IoT environment. and made the vision platform with 3D printing technology. Especially we used MongoDB for developing the performance of vision platform because the MongoDB is more akin to working with objects in a programming language than what we know of as a database. Afterwards, we would enhance the performance of vision platform for clouding functionalities.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.197-200
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• 2007

FCEV uses electric energy generated from fuel cell stack, thus all consisting parts must be re-designed to be suitable for electricity based system. Cathode air blower which supplies compressed air into fuel cell stack has similar shape of turbocharger, but a radial turbine of traditional turbocharger is removed and high speed BLDC motor is installed . Generally, maximum 10% of electric power of fuel cell stack is consumed in air blower, therefore an effective design of air blower can improve the performance of FCEV directly. This study will present an aerodynamic design process of an air blower and compare computational results with experimental data.

• 한국건축시공학회지
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• 제21권5호
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• pp.483-493
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• 2021

도시 인구의 과밀화로 고층 건물에 대한 폭발적인 수요와 공급이 발생하였다. 고층 빌딩은 각 도시의 구심점으로 도시 이미지를 제고하는데 기여하고 있으나 연돌효과로 인해 승강기 문의 오작동, 외벽의 문과 창문 개폐의 어려움, 상층부로 확산하는 연기와 악취, 소음, 에너지 손실, 화재 및 오염물질의 급속한 확산 등 예기치 못한 다양한 문제를 야기하고 있다. 본 연구에서는 초고층 건축물을 수직조닝별로 구분하여 연돌효과의 원인과 해결방안을 분석하고 설계와 시공 방안으로 도출하였다. 외기를 차단하는 초기 계획과 정밀한 시공을 통한 기밀성 확보를 통해 저층부에서 유입되는 기류를 능동적으로 차단하여 건물의 내·외부 기밀성을 확보하는 방안을 모색하였다. 설비적 해결대책은 연돌효과로 인한 특정 현상을 줄이기 위한 대책이 될 수 있으나 이에 따른 2차 피해의 가능성이 높기 때문에 최소한으로 적용해야 한다. 따라서 본 연구는 연돌효과의 원인과 대책방안을 수직 조닝별로 설계적, 시공적 대책을 제시함으로써 체계적인 연돌효과 관리의 필요성을 역설하였다. 또한 본 연구가 설계 및 시공뿐만 아니라 건물 유지관리에도 도움이 되기를 기대한다.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제20권12호
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• pp.658-663
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• 2014

OpenStack과 같이 오픈 소스 기반의 클라우드 컴퓨팅 관리 플랫폼 (Cloud Management Platform) 의 빠른 구현으로 인하여, 오픈 소스를 이용한 개인 및 기관의 클라우드 구축 시도가 지속적으로 증가되는 추세이다. 이러한 클라우드 운영자들에게, 구축한 클라우드 컴퓨팅 시스템의 동작 검증은 필수적이다. 본 논문은 클라우드 시스템 구축 검증하기 위한 오픈 소스 기반의 클라우드 테스트 도구를 디자인하며 구현한다. 특히, 제안된 테스트 도구는 오픈 소스 소프트웨어 프로젝트인 Tempest를 활용하며, Tempest의 테스트 케이스를 통해서 OpenStack기반의 클라우드를 검증한다. 제안된 소프트웨어는 국내에서 처음으로 개발되는 클라우드 시스템 구축 테스트 도구의 프로토타입이며, 앞으로 클라우드 기술 개발 및 사용자 확대에 기여할 것으로 예상된다.

• 대한산업공학회지
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• 제31권1호
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• pp.36-43
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• 2005

It is the basic requirement of design process of parts assembly to specify geometric dimensions and tolerances of product characteristics. Among them, tolerance stack analysis is one of the important methods to specify tolerance zone. Tolerance stack analysis is to calculate gap using tolerances which includes geometric and coordinate dimensions. In this study, we suggested more general method called the virtual method to analyze tolerance stack. In virtual method, tolerance zone is formed by combination of dimensional tolerance, geometric tolerance and bonus tolerance. Also tolerance zone is classified by virtual boundary condition and resultant boundary condition. So gap can be defined by combination of virtual boundary and/or resultant boundary. Several examples are used to show the effectiveness of new method comparing to other methods.

• 대한기계학회논문집B
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• 제30권11호
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• pp.1117-1122
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• 2006

The PEM type regenerative fuel cell(RFC) for the ground simulator of the regeneration electric power system has been designed, manufactured, and tested. In this paper, the designing and manufacturing procedures of the RFC were presented. Also, the performance test results were showed briefly. The RFC consists of PEM type stack, humidifier, pressure and flow control valve, storage tanks, pump and controller. The performance tests were carried out with stack and system performance tests. The performance targets are more than 50% stack efficiency, 1.5kW stack power, less 400W parasitic power in design condition. Most of the performances required are satisfied.