• Tribology and Lubricants
• /
• v.25 no.1
• /
• pp.61-65
• /
• 2009

Tribological properties of the semi-metallic friction materials containing different solid lubricants (graphite, $WS_2$, $MoS_2$) were investigated. The friction materials were fabricated with an experimental formulation and tested with gray cast iron disks. Results showed that graphite contributed to stabilize the friction coefficient during run-in processes. Also, graphite provided better fade resistance than that of $WS_2$ and $MoS_2$. At intermediate temperature ranges, however, friction materials with $WS_2$ or $MoS_2$ maintained higher friction effectiveness than that of graphite. On the other hand, friction materials containing $MoS_2$ showed increased wear rates than that with graphite or $WS_2$. Friction materials with proper combinations of two solid lubricants showed better friction and wear properties than that of the friction materials containing single solid lubricant.

• Journal of Platform Technology
• /
• v.6 no.4
• /
• pp.26-33
• /
• 2018

In this paper, we propose an image retrieval algorithm for real-time processing and design it as hardware. The proposed method is based on the classification of BoWs(Bag of Words) algorithm and proposes an image search algorithm using bit stream. K-fold cross validation is used for the verification of the algorithm. Data is classified into seven classes, each class has seven images and a total of 49 images are tested. The test has two kinds of accuracy measurement and speed measurement. The accuracy of the image classification was 86.2% for the BoWs algorithm and 83.7% the proposed hardware-accelerated software implementation algorithm, and the BoWs algorithm was 2.5% higher. The image retrieval processing speed of BoWs is 7.89s and our algorithm is 1.55s. Our algorithm is 5.09 times faster than BoWs algorithm. The algorithm is largely divided into software and hardware parts. In the software structure, C-language is used. The Scale Invariant Feature Transform algorithm is used to extract feature points that are invariant to size and rotation from the image. Bit streams are generated from the extracted feature point. In the hardware architecture, the proposed image retrieval algorithm is written in Verilog HDL and designed and verified by FPGA and Design Compiler. The generated bit streams are stored, the clustering step is performed, and a searcher image databases or an input image databases are generated and matched. Using the proposed algorithm, we can improve convenience and satisfaction of the user in terms of speed if we search using database matching method which represents each object.

• Journal of the Semiconductor & Display Technology
• /
• v.17 no.3
• /
• pp.31-35
• /
• 2018

Tungsten disulfide($WS_2$) thin films were directly deposited by direct-current(DC) sputtering and annealed by rapid thermal processing(RTP) to materialize two-dimensional p-type transition metal dichalcogenide (TMDC) thin films on soda-lime glass substrates without any complicated exfoliation/transfer process. $WS_2$ thin films deposited at various DC sputtering powers from 80 W to 160W were annealed at different temperatures from $400^{\circ}C$ to $550^{\circ}C$ considering the melting temperature of soda-lime glass. The optical microscope results showed the stable surface morphologies of the $WS_2$ thin films without any defects. The X-ray photoelectron spectroscopy (XPS) results and the Hall measurement results showed stable binding energies of W and S and high carrier mobilities of $WS_2$ thin films.

• Proceedings of the CALSEC Conference
• /
• 2003.09a
• /
• pp.109-114
• /
• 2003

WS-BPMS(web service driven business process management system)은 기업 내 또는 비즈니스 파트너들 간의 비즈니스 프로세스를 체계적으로 통합, 관리하여 프로세스를 개선하고 자동화한다. 이는 비즈니스 프로세스를 검색한 후 BPEL4WS, BPML 등의 프로세스 메타모델을 이용하여 새 프로세스를 디자인하고 BPMS위에 전개 실행하는 과정을 거치게 된다. 디자인된 프로세스는 복잡하여 그 실행에 있어 체계적이고 확고한 기반을 바탕으로 운영되어야 한다. 이를 위해 본 논문에서는 BPMS의 운영에 있어 pi-calculus를 기반으로 한 structured exception handling 방법론과 transaction 모니터링을 통한 backward recovery 방법을 제시한다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.10c
• /
• pp.661-663
• /
• 2002

웹을 이용한 서비스는 위와 같은 여러 장점을 가지고 있지만 각종 데이터 및 문서가 웹 상에 존재하므로 가상공간에서의 문서의 처리가 위조나 변경이 가능하다. 이러한 웹 상에서의 전송 시 발생할 수 있는 수많은 역기능들을 줄일 수 있는 가장 강력한 방법은 암호 옹용 기술을 전자상거래 시스템 구축에 사용함으로써, 기밀성(confidentiality), 무결성(integrity), 인증(authentication) 등의 보안 서비스를 제공하는 것이다. 이에 본 논문에서는 현재 진행중인 표준화 단체의 동향을 파악하고 WS-Security 명세서를 통해 웹 서비스 보안의 전반적인 기술을 분석한다.

• The Journal of the Acoustical Society of Korea
• /
• v.22 no.1E
• /
• pp.26-32
• /
• 2003

We propose new time-frequency (TF) tools for analyzing linear time-varying (LTV) systems and nonstationary random processes showing hyperbolic TF structure. Obtained through hyperbolic warping the narrowband Weyl symbol (WS) and spreading function (SF) in frequency, the new TF tools are useful for analyzing LTV systems and random processes characterized by hyperbolic time shifts. This new TF symbol, called the hyperbolic WS, satisfies the hyperbolic time-shift covariance and scale covariance properties, and is useful in wideband signal analysis. Using the new, hyperbolic time-shift covariant WS and 2-D TF kernels, we provide a formulation for the hyperbolic time-shift covariant TF symbols, which are 2-D smoothed versions of the hyperbolic WS. We also propose a new interpretation of linear signal transformations as weighted superposition of hyperbolic time shifted and scale changed versions of the signal. Application examples in signal analysis and detection demonstrate the advantages of our new results.

• 한국경영정보학회:학술대회논문집
• /
• 2007.11a
• /
• pp.389-394
• /
• 2007

웹 서비스가 현재 산업에서 주요한 분산 컴퓨팅 기술로 대두되면서, 그에 따른 연구가 활발히 이루어지고 있다. 특히, 비즈니스 프로세스 관점에서 BPEL4WS (Business Process Execution Language for Web Services)와 같은 오케스트레이션의 연구가 많이 이루어지고 있다. 또한, 웹 서비스의 주요 구성 요소중에 하나인 코리오크래피에 대한 부분은 W3C (World Wide Web Consortium)에서 현재 후보 권고안 수준인 WS-CDL (Web Services Choreography Description Language) 관련 연구가 이루어지고 있다. 이런 가운데 DERI (Digital Enterprise Research Institute)에서 WSMX (Web Services Execution Environment) 기반의 시맨틱 웹 서비스 분야의 코리오 그래피 연구를 시작하였고, 코리오그래피 불일치 (Mismatch)를 개념적으로 해결하는 방안인 프로세스 미디에이션 (Process Mediation)의 연구가 있었다. 이러한 연구들을 바탕으로 서로 다른 WS-CDL 상에서 특정 참여자가 코리오그래피 미디에이션을 하기위해서 개발된 XML 언어 WS-CML (Web Services Choreography Mediation Language)을 본 논문에서 제안한다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05a
• /
• pp.611-616
• /
• 1997

The Level 1 probabilistic safety assessment(PSA) for Wolsong(WS) 2/3/4 nuclear power plant(NPPs) in design stage is performed using the methodologies being equivalent to PWR PSA. Accident sequence evaluation program(ASEP) human reliability analysis(HRA) procedure and technique for human error rate prediction(THERP) are used in HRA of WS 2/3/4 NPPs PSA. The purpose of this paper is to introduce the procedure and methodology of HRA in WS 2/3/4 NPPs PSA. Also, this paper describes the interim results of importance analysis for human actions modeled in WS 2/3/4 PSA and the findings and recommendations of administrative control of secondary control area from the view of human factors.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.05a
• /
• pp.714-717
• /
• 2004

In this paper, we describe issues related to standardized interaction among companies that are in the environments of heterogeneous information systems. The interaction method is detailed based on BPEL4WS, which is XML based standard specification. This paper provides method of interoperability using web service, which is considered a new information system paradigm. The method has importance in that it enables to exchange data in a platform independent manner. This paper deals with a method of interaction among heterogeneous information system based on BPEL4WS standard. The concepts of interoperability, XML, and workflow are introduced. The standards and previous research results related to interoperability are also provided. It describes brief introduction of BPEL4WS specification and its technical details. Integrated business process using BPEL4WS and interoperability issues are also included..

• Journal of the Korea Furniture Society
• /
• v.19 no.3
• /
• pp.172-179
• /
• 2008

The objective of this study was to investigate the influence of the water repellents' treatment on the water absorptivity and the dimensional stability of Korean red pine wood(Pinus densiflora). The alkylketene dimer(AKD), fluororesin emulsion(Wood-seal, WS), and paraffin wax emulsions(PW25, PW40, and PW1200) were used as water repellents. PW40 and WS were proved as excellent water repellents for pine wood, because the samples treated with these agents showed high contact angles and large reduction in water absorptivities. Also, the dimensional stability(antiswelling efficiency) of pine wood was considerably improved by water repellents treatments, such as PW40 and WS at the pressure of 2MPa. The water repellent treated woods with WS, PW40, and PW1200 at the pressure of 2MPa were relatively stable to the wet-dry cyclic leaching test.