합금공구강 와이어직선 방전가공면의 신뢰성 평가

김일수,성백섭,김인주,정영재,손준식 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

The purpose of this study was to present the method to choose the optimization machining condition for the wire electric machine. This was completed by examining the ever-changing quality of the material and by improving the function of the wire electric discharge machine. Precision metal mold products and the unmanned wire electric discharge machining system were used and then applied in industrial fields. This experiment uses the wire electric discharge machine with brass wire electrode of 0.25mm. To measure the precision of the machining surface, average values are obtained from 3 samples of measures of center-line average roughness by using a third dimension gauge and a stylus surface roughness gauge.

스마트 안테나에서 블라인드 기법을 이용한 Two Dimensional RAKE 수신기

박형준,이철형,최명수,김경호,이성로 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

Smart antennas technique is the scheme that focuses the signal on the desired user using array antennas. Therefore, the scheme can dramatically improve performances in conventional mobile communication systems. The scheme is the newest technique for beamforming. Its specific function combines antenna arrays with digital signal processing techniques that can control signal direction. Now, the scheme is known as the future generation core technique in communication provider communities. In this paper, we propose two dimensional rake receiver based on blind schemes in smart antennas and then compare the performance of the proposed scheme with that of the conventional scheme. Computer simulation results show that the proposed scheme outperforms the conventional scheme.

Schiff Base에 의한 구리 부식 억제

정병구,이현석,장영학,문채주 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

The inhibiting action of copper in 5% hydrochloric acid(HCI) solutions with or without Schiff base, 1,2-bis(naphthylideneimine)ethane(NET), 1,3-bis(naphthylideneimine) propane(NPR), 1,4-bis(naphthylideneimine)butane(NBU), and 1,5-bis(naphthylideneimine) pentane(NPE), has been studied by the Tafel method and AC impedance technique. The corrosion parameters were obtained at different inhibitor concentrations and the temperature effect was also investigated. The inhibiting efficiency increases with a decrease in temperature or increase in concentration of the Schiff base. NPE is the best inhibitor in this series and the maximum inhibition efficiency at a concentration of 5×10^-4 M at 298 K approached 90.07%. Schiff base with longer-chain are superior to shorter-chained analogues in inhibition efficiency.

정밀 사출성형을 위한 수치해석에 관한 연구

이상찬,윤한용 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

To simulate the real molding conditions, the effects of phase change and compressibility of the resin were considered in the present investigation. A modified Cross model with either an Arrhenius-type or WLF-type functional form was used for modeling viscosity of the resin. A double-domain Tait equation of state was employed to describe the compressibility of the resin during molding. The energy balance equation including latent-heat dissipation for semi-crystalline materials was solved in order to predict the solidified layer and temperature profile. Injection molding experiments were carried out using polypropylene(PP) in the present study. Based on the comparison between experiments and simulations, it was found out the predicted pressure distributions and melt front propagations were accurate. Thus it was concluded that the program developed in this study was proved to be useful in simulations of injection molding process.

습식 가스미터의 성능에 관한 연구

장석,윤복현 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

The performance of a wet gas meter using water as a sealing liquid was tested by means of a standard gas flow measuring system operating at the room temperature in Korean Research Institute of Standards and Science (KRISS). The original data from the wet gas meter were calibrated by using the humidity measured at the meter exit. As a result, the error of the wet gas meter was decreased remarkably. This means that humidity affects the performance of the wet gas meter significantly. These data and results are expected to be used as bases for further researching and developing various wet gas meters afterwards.

네트워크 통신 보안을 위한 암호화 조건부 접속시스템

박남철,이철형,최명수,김경호,이성로 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

We can improve encryption speed at the home networking which transmit high density information. In this paper, We applicate DES encryption algorithm in the proposed encryption chip which dose operation that encrypts with block of 64 bits. And we improved key problems about transmitting external key by the conditional contact algorithm which solves the problem about periodical refresh in the symmetric algorithm with public key structure.

도시소각회의 재활용 기술로서 내부발열소결법의 적용성

나춘기,정일현 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

This paper describes the use of municipal solid waste incinerator (MSWI) ashes to manufacture synthetic aggregates using an innovative sintering technique, which was named "inner exothermic sintering (IES) method", characterized by co-treatment of sewage sludge as an inner heating source. The results of sintering experiments indicate that the added sewage sludge has powerfully acted as an inner heating source and a bloating agent in the sintering process of pellet, and thus could be manufacture of a double layered MSWI ash aggregate with fusion-bloated inner part and nonfusion dense outer surface. Futhermore, in this process, the fly ash also be co-treated without any particular change of the sintering condition. The synthetic aggregates are tested according to US regulation and fulfill regulatory limits, therefore, confirming their safe applications, although the results show some higher leaching from sintered aggregates than from melted slags. An overall conclusion from this is that the IES method represents an environment friendly and a solution for stabilising and converting MSWI ashes and sewage sludges into useful products.

NPMS를 이용한 통신망 품질개선 및 운용보전 성과분석에 관한 연구

기규도,김경호,이성로 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

It is necessary to measure the network quality for operating the stable network and Analyze its results for application of Network Quality Improvement on the Basis of Network Quality Improvement by NPMS and Preservation a Result Analysis. This study is to measure and analyze each network quality using NPME log based on standard of network quality measurement, and suggest as follows: Firstly, it presents the management of communication rate that enable to communicate to each network smoothly, measuring quality for subscriber line by vocal and non-vocal using telephone network, connection quality through the DTD and PDD after dialed, and the standards of electrical transmission that measures the loss of transmission quality, Psophometric Noise, SNR, Phase Jitter, BER.

X-cut LiNbO_3 광도파로 제작 및 패턴 특성

정운조,김성,박계춘 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

The optical near field patterns, propagation loss and mode sizes of x-cut Ti:LiNbO_3 optical waveguide which was fabricated by Ti-diffusion varying with Ti strip thickness in wet oxygen atmosphere were investigated and tested at optical wavelength 1550nm. As Ti thickness increased from 760Å, the insertion loss of waveguide was decreased. But at Ti thickness 1500Å, mode sizes are widely broadened. This Ti thickness of below 1100Å and above 1500Å showed negative effects to propagation loss and fiber coupling. The best Ti thickness for fabricating low propagation loss and good fiber coupling. The best Ti thickness for fabricating low propagation loss and good fiber coupling was inferred to be between 1100Å-1500Å in our conditions. And for Ti thickness 1150Å, its propagation loss, horizontal/vertical mode sizes were measured 1.61dB/cm, 11.9/8.9㎛ for TM, 0.22dB/cm, 12.0/9.1㎛ for TE respectively.

문자패턴의 특징지도 추출을 위한 상대유사 경쟁학습 알고리즘

유영재,이진,장영학,김성환 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

In this paper, we propose a new competitive learning algorithm for unsupervised learning neural network to extract a feature map from letter patterns. The proposed learning algorithm is based on relative similarity, which is similarity measure between input data and cluster group. So, the proposed network and algorithm is called relative similarity network (RSN) and learning algorithm. According to the definition of similarity and learning rule, the structure of RSN is designed and the pseudo code of the algorithm is described. In the extraction of a feature map. RSN, in spite of deletion of learning rate, resulted in the identical performance with those of WTA, and SOM. Thus, it is shown that RSN is useful to extract a feature map of letter patterns.