• Journal of Information Processing Systems
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• 제14권1호
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• pp.140-149
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• 2018

Social data such as users' comments are unstructured in nature and up-to-date technologies for analyzing such data are constrained by the available storage space and processing time when fast storing and processing is required. On the other hand, it is even difficult in using a huge amount of dynamically generated social data to analyze the user features in a high speed. To solve this problem, we design and implement a topic association analysis system based on the latent Dirichlet allocation (LDA) model. The LDA does not require the training process and thus can analyze the social users' hourly interests on different topics in an easy way. The proposed system is constructed based on the Spark framework that is located on top of Hadoop cluster. It is advantageous of high-speed processing owing to that minimized access to hard disk is required and all the intermediately generated data are processed in the main memory. In the performance evaluation, it requires about 5 hours to analyze the topics for about 1 TB test social data (SNS comments). Moreover, through analyzing the association among topics, we can track the hourly change of social users' interests on different topics.

• 한국인터넷방송통신학회논문지
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• 제21권4호
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• pp.43-49
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• 2021

소형 적외선영상 호밍시스템은 지상의 표적에 대하여 주야간 적외선 영상처리를 통하여 표적을 식별하고 주요 표적에 대하여 표적을 탐색, 탐지하여 추적하는 적외선 영상센서를 보유한 추적시스템이다. 본 논문에서는 지상의 표적을 주야간 적외선 영상을 통하여 표적 정보를 획득하여 실시간 영상처리를 통하여 표적을 식별하기 위한 고속의 CPU와 FPGA(Field Programmable Gate Array)가 탑재된 보드 개발의 내용을 설명한다. CPU, FPGA 선정과 영상신호처리를 위한 CPU-FPGA 결합 아키텍처에 대하여 제안하고 또한 김발구조의 적외선센서를 제어하기 위한 FPGA를 활용에 대하여 설명한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.336-340
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• 1996

This paper presents the development of a collocated capacitance sensor and its application to the decentralized PID controller design for 4-axis magnetic bearing system. The main feature of the sensor is that it is made of a compact printed circuit board (PCB) so that it can be built in to the actuator coil of the magnetic bearing unit. The signal processing unit has been also developed. Then, decentralized PED controller is designed using simplified rotor system model. Finally, the experimental results on the performance of the collocated sensor based decentralized PID controller for a magnetic bearing rotor system is presented.

• 한국광학회지
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• 제5권2호
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• pp.225-230
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• 1994

홀로그래피 HUD의 제작에 필요한 주요 파라미터를 살펴보고 이들 값을 결정하기 위한 관계식을 유도하여 설계 값을 설정하였다. 기록 방법으로는 간섭무늬에 의한 잡음을 최소화할 수 있는 공기층 반사 기록방법을 제시하였다. 특히, DCG필름을 처리한 후에 생기는 중심파장의 이동을 보정하기 위한 새로운 방법을 소개하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.409-412
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• 1998

In this paper, we present an $H^2$ controller design of RTP(rapid thermal processing) systems satisfying robust stability and performance using weighted mixed sensitivity minimization. In industrial fields, RTP system is widely used for improving the oxidation and the annealing in semiconductor manufacturing process. The main control factors are temperature control of wafer and uniformity has been solved by PID control method. Because the reference inputs of RTP are ramp, we improve performance of RTP system by the design of $H^2controller$ using the weighted mixed sensitivity function. Also we compare $H^2controller$ with PID controller in terms of performance. An example is proposed to show the validity of proposed method.

• 디지털산업정보학회논문지
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• 제5권1호
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• pp.51-61
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• 2009

Conventional DES has been not only shown to have a vulnerable drawback to attack method called 'Meet in the Middle', but also to be hard to use that it is because software implementation has a number of problem in real time processing. This paper describes the design and implementation of the expanded DES algorithm using VHDL for resolving the above problems. The main reason for hardware design of an encryption algorithm is to ensure a security against cryptographic attack because there is no physical protection for the algorithm written in software. Total key length of 352 bits is used for the proposed DES. The result of simulation shows that the inputted plaintext in cryptosystem are equal to the outputted that in decryptosystem.

• 소성∙가공
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• 제12권1호
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• pp.18-25
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• 2003

This paper explains the process design for improving tool life in the conventional hot forging process. The thermal load and the thermal softening are happened by contact between the hotter billet and the cooler tools in hot forging process. Tool life decreases considerably due to the softening of the surface layer of a tool was caused by a high thermal load and long contact time between the tools and the billet. Also, tool life is to a large extent limited by wear, heat crack and plastic deformation in hot forging process. Above all, the main factors which affect die accuracy and tool life we wear and the plastic deformation of a tool. The newly developed techniques for predicting tool life are applied to estimate the production quantity for a spindle component and these techniques can be applied to improve the tool life in hot forging process.

• 한국실내디자인학회논문집
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• 제13권3호
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• pp.162-170
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• 2004

The purpose of this study is to analyze the emotional color of home office and the trendy color with special comparison of office and library colors, and to suggest the harmony of color combination of home office based on the emotional color of this analytical data. this study, the Color Syntax Program, digital tool for color analysis of images is used. The results of this study are as follows. Firstly, the main color of home office images shows three color classifications of YR-Y, Y-GY, R-YR, and with relatively high ratios of YR-Y in the color of home offices, and B-PB, GY-G in offices and libraries. Secondly, from the point of emotional aspect, the trendy color of the home office can be classified into four color image categories: 'natural', 'peaceful', 'mild', and 'noble'. Under those categories this paper proposes 10 color harmony scheme that can be applied to color of home office interior design.

• ETRI Journal
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• 제22권1호
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• pp.1-11
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• 2000

The Satellite Operation System (SOS) has been developed for a low earth orbiting remote sensing satellite, Korea Multipurpose Satellite-I, to monitor and control the spacecraft as well as to perform the mission operation. SOS was designed to operate on UNIX in the HP workstations. In the design of SOS, flexibility, reliability, expandability and interoperability were the main objectives. In order to achieve these objectives, a CASE tool, a database management system, consultative committee for space data systems recommendation, and a real-time distributed processing middle-ware have been integrated into the system. A database driven structure was adopted as the baseline architecture for a generic machine-independent, mission specific database. Also a logical address based inter-process communication scheme was introduced for a distributed allocation of the network resources. Specifically, a hotstandby redundancy scheme was highlighted in the design seeking for higher system reliability and uninterrupted service required in a real-time fashion during the satellite passes. Through various tests, SOS had been verified its functional, performance, and inter-face requirements. Design, implementation, and testing of the SOS for KOMPSAT-I is presented in this paper.

• 소성∙가공
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• 제8권6호
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• pp.591-603
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• 1999

A computer-aided process planning system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has been reported yet. Therefore, this study investigates process sequence design in deep drawing process and constructs a computer-aided process planning system for non-axisymmetric motor frame products with elliptical shape. The system developed consists of three modules. The first one os a 3-dimensional modeling module to calculate surface area for non-axisymmetric products. The second one is a blank design module that creates an oval-shaped blank with the identical surface area. The third one is a process planning module based on production rules that play the best important roles in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers. Especially, drawing coefficient, punch and die radii are considered as main design parameters. The constructed system for elliptical deep drawing products would be very useful to reduce lead time and improve accuracy for production.