α型 Stirling Engine 開發을 爲한 理論解析 및 電算化 硏究

李澤熙,李鍾元 慶熙大學校 大學院 院友會 1991 高凰論集 Vol.8 No.-

A Stirling engine is a mechanism used to convert heat to power and operates on a closed regenerative thermodynamic cycle heat engine with compression and expansion of the working fluid at different temperature. According to the classical Schmidt theory, the performance of a stirling cycle machine is a function of six independent paramenter, namely; ⑴ speed ⑵ pressure of the working fluid ⑶ ratio of the temperature in the compression and expansion spaces. ⑷ ratio of the swept volume in the compression and expansion spaces. ⑸ phase angle ⑹ volume of the heat exchangers and regenerators. The four parameter ⑶∼⑹ must be selected at the design stage of the stirling cycle machine. The paper describes the procedure and presents the results of computations carried out to establish the optimum combinations of these four parameters for maximum engine output for the machine acting as a prime mover over a combined temperature range from 300 to 3000˚K. The output of a stirling cycle machine can be expressed in terms of non-dimensional power in several different ways. four methods were studied in detail, the parameters optimized and design charts prepared. Wide variations in the optimum parameter combinations were obtained and a partial explanations of this phenomenon is offered. Pressure-volume diagrams for the stirling cycle machines of the same size were prepared for the four different parameter combinations. Maximum output was obtained from the stirling cycle machine designed on a basis of limited maximum pressure and total swept volume. The one chart relating to the case for prime mover optimized with regard to the maximum cycle pressure and total swept volume are recommended for use in future design work.

부랑인 정신질환자의 특성에 관한 조사

이택희 慶北大學校 醫科大學 情神醫學敎室 1992 對話 Vol.8 No.15

인증을 위한 IMT - 2000 서비스 및 보안체계 분석

이택희 호남대학교 정보통신연구소 1997 정보통신연구 Vol.6 No.-

이동통신서비스는 차후 전세계적인 호환성을 보장하는 IMT-2000 망으로 진화할 것으로 예측된다. 한편 이동통신서비스는 무선통신망의 특성에 기인한 불법적인 사용이나 도청 또는 추적을 통한 불법적 행위와 각종 통신 범죄 행위등에 대한 대책이 필요하며, 이를 위하여 망은 인증기능을 제공해야 한다. 본 논문은 차세대 이동통신망으로 약속되는 ITM-2000 망에서 인증기능을 제공하기 위하여, 현재 표준화가 진행중에 있는 IMT-2000 서비스와 보안세계를 분석한 것이다. Digital mobile communication networks offer securities and authentication services to protect the unauthorized or illegal use of a cellular telephone or cellular network resources. And IMT-2000 system will provide an access to the wide range of advanced voice and non-voice communication services and guarantee global terminal mobility and unified common air interface. This paper analyses the IMT-2000 services and security functions for authentication. and all analysis are based on ITU recommendation. More works on cryptographic system and related protocol analysis will be continued to design a security management system for IMT-2000.

디지틀 이동통신망의 인증기법연구

이택희 湖南大學校 1996 호남대학교 학술논문집 Vol.17 No.2

CDMA mobile network offers security and authentication functions to protect the unauthorized or illegal use of a cellular telephone or cellular network resources. This paper forcused on the analysis of authentication techniques and load for authentication services. Various network models are presented to compare the merit on some check points. The following items are the results of analysis. 1) Authentication center should be an isolated entity. 2) There should be connections between AC and MSC/VLR, HLR respectively. 3) All authentication related functions are performed by AC. 4) Good selection of subscriber and time is needed to reduce the network load. More work on authentication policy for selection is needed to reduce the authentication load Authentication load for network is the biggest problem to provide authentication services.

제어용 언어로서의 Ada

이택희,송경준,김용준,Lee, Teag-Heui,Song, Gyeong-Jun,Kim, Yong-Jun 한국전자통신연구원 1988 전자통신 Vol.10 No.4

Ada는 Embedded 시스팀을 위한 고급 프로그래밍 언어이다. 여기서는 Ada가 지닌 제어시스팀 개발용 언어로서의 특징을 살피고 Ada 개발환경인 APSE(Ada Programming Support Environment)를 분석하여 제어시스팀 개발에 응용할 수 있도록 하고자 한다.

무선인터넷 보안 프로토콜 적용방안

이택희 호남대학교 2000 호남대학교 학술논문집 Vol.21 No.2

Wireless data and internet are growing very quickly. But most of the technology developed for the internet has been designed for desktop and large computers. There environment provide wide bandwidth and generally reliable data networks. Wireless Internet is similar to wired internet, but it has some constrained wireless environment. So many internet technologies for wireless are developing now. There are WAP (Wireless Application Protocol) and WPKI. WAP is a protocol specification for wireless communication networks. It provides an application framework and network protocols for wiress devices such as mobile telephones, PDAs(Personal Digital assistants) and internet technologies. In this paper some analysis of security protocol for wireless internet are performed. In the result, better suitable protocol stack design is possible and is easy to implement.

차세대 Router 구현 전략

이택희 호남대학교 정보통신연구소 2000 정보통신연구 Vol.10 No.-

The primary role of router is to transfer packets from input links to output links. They must also deal with heterogeneous link technologies, provide scheduling support for differential services and participate in complex distributed algorithms to generate routing tables. These demand complicate their design. The rapid growth of the internet has created different challenges for routers on backbone network and access networks. Here are some analysis for designing the high speed router and active router for next generation internet are performed.

가상 드론 시뮬레이터 구축을 위한 시스템 구성

이택희 한국차세대컴퓨팅학회 2017 한국차세대컴퓨팅학회 논문지 Vol.13 No.6

최근 드론은 배송, 농업, 공업, 엔터테인먼트 등 다양한 분야에 적용되어 사용 영역을 넓히고 있다. 실제 드론을 제어하기 위해선 많은 경험이 필요하지만 이를 위해선 드론 분실, 파손 등 여러 위험한 상황에 노출되기 쉽다. 가상드론 시스템은 이러한 위험성을 피하여 드론을 학습 할 수 있는 배경을 제공할 수 있다. 본 논문에서는 드론 학습을위한 가상 드론 시스템 구축을 위한 요구기술들에 대해 논한다. 먼저, 다양한 형태를 가질 수 있는 드론을 가상의환경에서 조립할 수 있는 저작도구가 필요하다. 가상의 저작도구는 실제 드론의 물리적 특성을 반영할 수 있어야 한다. 이에 실제 비행에 큰 영향을 비치는 로터의 위치나 배선의 간섭 등을 고려할 수 있는 가상 드론 저작 도구를 제안한다. 다음으로는 만들어진 가상의 드론을 실제 비행환경과 흡사한 물리적 조건하에서 구동 해 볼 수 있는 가상드론 시뮬레이터가 필요하다. 이 시뮬레이터는 실제와 근접한 렌더링 품질을 보장할 수 있어야 하며 기체 역학에 근거한 물리적 환경 하에 구동이 되어야 한다. 여기에 가상 드론의 동역학적 특징이 움직임에 반영 될 수 있도록SILS(Software in the loop simulation) 기반의 검증 기법을 추가하여 사실성을 높인다. 마지막으로 실제 드론컨트롤러 기반으로 가상의 드론을 구동할 수 있는 환경이 필요하다. 범용으로 사용되는 드론 컨트롤러의 신호를 시뮬레이터에서 받아 사용할 수 있는 가상 드론 컨트롤러 기술을 제안한다. 완성된 가상드론 저작도구, 시뮬레이터, 및 컨트롤러 연동 기술을 포함한 가상 드론 시스템은 100명의 사용자 대상 만족도 조사 결과 10점 기준 7.64의 만족도를 나타내었다. Recently, drone is extending its range of usability. For example, the delivery, agriculture, industry, and entertainment area take advantage of drone mobilities. To control real drones, it needs huge amount of drone control training steps. However, it is risky; falling down, missing, destroying. The virtual drone system can avoid such risks. We reason that what kinds of technologies are required for building the virtual drone system. First, it needs that the virtual drone authoring tool that can assemble drones with the physical restriction in the virtual environment. We suggest that the drone assembly method that can fulfill physical restrictions in the virtual environment. Next, we introduce the virtual drone simulator that can simulate the assembled drone moves physically right in the virtual environment. The simulator produces a high quality rendering results more than 60 frames per second. In addition, we develop the physics engine based on SILS(Software in the loop simulation) framework to perform more realistic drone movement. Last, we suggest the virtual drone controller that can interact with real drone controllers which are commonly used to control real drones. Our virtual drone system earns 7.64/10.0 user satisfaction points on human test: the test is done by one hundred persons.

PKI를 활용한 안전한 운영체제 구조

이택희 호남대학교 1999 호남대학교 학술논문집 Vol.20 No.2

In this paper, some basic techniques are proposed to protect computer virus. They are based on PKI(Public Key Infrastructure). First, file integrity is offered by producer's signature, so modified program can be detected easily. Second, virus programming can be protected by authenticated relationship between file and producer. it is possible by certificate offered by CA(Certification Authority) of PKI. The last technique is to define 'file action type'. By this method, all program can be monitored by operating system. Basically all these techniques are based on PKI and change of conventional OS.

통신망 전용 컴퓨터의 기반구조 연구

이택희 호남대학교 1995 호남대학교 학술논문집 Vol.16 No.2

In modern telecommunication applications, more and more attention is paid to flexibility. This flexibility can only be provided by increasing the processing power in the overall network and in every switching point. As a result, computers were introduced in the telephone network. Today, very high reuirements are put on telecommunication computers. This paper presents some analysis of telecommunication system and requirements for telecommunication computers. Also this paper proposes a basic architecture for embedded communication computer. This architecture is specifically designed for telecommunication applications. Future work be forcused on detail design and implementation.