• Journal of Magnetics
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• 제11권3호
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• pp.143-146
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• 2006

We attempted to fabricate a new type of magneto optic spatial light modulator (MO-SLM) for multiple-tone modulation by using in-plane magnetization. In the MO-SLM, magnetic property of magneto-optical layer was modified to be suitable for multiple-tone expression by substituting Al in Bi:YIG film. At a driving current to 28 mA in an electrode of the fabricated MO-SLM, changes in brightness of pixels were observed using a polarization microscope.

• 대한전자공학회논문지
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• 제21권3호
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• pp.13-18
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• 1984

Horizontal microprogram에서 MO'S(microoper&titans)의 concurrency와 resource의 할당을 고려하여 MO'S을 병렬로 수행할 수 있는 알고리즘을 제안한다. 본 알고리즘은 SLM(straight line microprogram) 상에 있는 각 MO에 weight를 부여함으로써 병렬 실행될 수 있는 MO'S을 1개의 MI(microinstruction)으로 결합하여 전체 MI수를 최소화시킴으로써 실행 시간과 microprogramed 디지탈 시스템의 제어기억장치 크기(space)를 감소시키는 결과를 얻을 수 있다.

• 한국정보시스템학회지:정보시스템연구
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• 제16권3호
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• pp.69-90
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• 2007

Recently, Service Level Management(SLM) including SLA has been developing to manage the level of information systems service. Although previous SLA studies have provided the conceptual model and critical success factors, the studies have not tested the effectiveness of the SLA by way of the empirical study. In this study, we applied an innovation decision making theory to our model and tested an empirical study using of a firm survey data. We suggested a SLM model, which consists of SLA planning, application, management dimensions. We found that the SLM's management stage has an impact on performance, whereas SLM's planning and application has not. At each sub dimensional analysis, there are found that adequate SLA indicators in the application stage influences performance and change management and feedback & reporting in the management stage influence performance.

• 대한치과기공학회지
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• 제37권1호
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• pp.23-29
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• 2015

Purpose: The selective laser melting (SLM) process for dentistry, which is one of the additive manufacturing technologies (AM) allows for rapid production of a three-dimensional model with complex shape by directly melting metal powder. This process generates detailed items of a three-dimensional model shape through consolidation of a thin powder layer by utilizing both selective melting and laser beam simultaneously. In regard to SLM process, Fe-base powder, Ti-6AI-4V powder, AI-base powder, etc. have been researched. It is believed that the aforementioned technologies will be widely utilized in manufacturing metal parts using metal powder of raw material. This study chose Ni-Cr-Mo metal powder in order to manufacture metal powder materials that would be used in the selective laser melting for dentistry. Methods: This study manufactured metal powder using mechanical alloying technique (MA) among those metal powder manufacturing techniques. Moreover, this study aimed to utilize the metal powder manufactured after observing the characteristics of powder as preliminary data of Ni-Cr-Mo metal powder. This study could obtain the following conclusions within the experimental limitations. Results: As a result of mechanically alloying Ni-Cr-Mo powder over time, its mean particle size was $66.93{\mu}m$ $54.4{\mu}m$ and $45.39{\mu}m$ at 10h, 20h and 30h, respectively. The gtain form of metal powder by mechanical alloying technique was a sponge-like shape of irregular plate; however, the gtain form manufactured by high-pressure water aromization process had the following three types: globular type, chain type and oval type. Conclusion: This study found $37.65{\mu}m$ as the mean particle size of Ni-Cr-Mo metal powder, which was manufactured using water atomization technique under the following conditions: water atomization flux of 300 liter/min, hydraulic pressure of $400kgf/cm^2$ and injection angle of $45^{\circ}$. This study confirmed that the grain form of powder (solid particle form) would vary depending on the manufacturing process.

• Asia pacific journal of information systems
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• 제23권2호
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• pp.21-39
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• 2013

As the utilization of information technology and the turbulence of technological change increase in organizations, the adoption of IT outsourcing also grows to manage IT resource more effectively and efficiently. In this new way of IT management technique, service level management(SLM) process becomes critical to derive success from the outsourcing in the view of end users in organization. Even though much of the research on service level management or agreement have been done during last decades, the performance of the service level management process have not been evaluated in terms of final objectives of the management efforts or success from the view of end-users. This study explores the relationship between SLM maturity and IT outsourcing success from the users' point of view by a analytical case study in four client organizations under an IT outsourcing vendor, which is a member company of a major Korean conglomerate. For setting up a model for the analysis, previous researches on service level management process maturity and information systems success are reviewed. In particular, information systems success from users' point of view are reviewed based the DeLone and McLean's study, which is argued and accepted as a comprehensively tested model of information systems success currently. The model proposed in this study argues that SLM process maturity influences information systems success, which is evaluated in terms of information quality, systems quality, service quality, and net effect proposed by DeLone and McLean. SLM process maturity can be measured in planning process, implementation process and operation and evaluation process. Instruments for measuring the factors in the proposed constructs of information systems success and SL management process maturity were collected from previous researches and evaluated for securing reliability and validity, utilizing appropriate statistical methods and pilot tests before exploring the case study. Four cases from four different companies under one vendor company were utilized for the analysis. All of the cases had been contracted in SLA(Service Level Agreement) and had implemented ITIL(IT Infrastructure Library), Six Sigma and BSC(Balanced Scored Card) methods since last several years, which means that all the client organizations pursued concerted efforts to acquire quality services from IT outsourcing from the organization and users' point of view. For comparing the differences among the four organizations in IT out-sourcing sucess, T-test and non-parametric analysis have been applied on the data set collected from the organization using survey instruments. The process maturities of planning and implementation phases of SLM are found not to influence on any dimensions of information systems success from users' point of view. It was found that the SLM maturity in the phase of operations and evaluation could influence systems quality only from users' view. This result seems to be quite against the arguments in IT outsourcing practices in the fields, which emphasize usually the importance of planning and implementation processes upfront in IT outsourcing projects. According to after-the-fact observation by an expert in an organization participating in the study, their needs and motivations for outsourcing contracts had been quite familiar already to the vendors as long-term partners under a same conglomerate, so that the maturity in the phases of planning and implementation seems not to be differentiating factors for the success of IT outsourcing. This study will be the foundation for the future research in the area of IT outsourcing management and success, in particular in the service level management. And also, it could guide managers in practice in IT outsourcing management to focus on service level management process in operation and evaluation stage especially for long-term outsourcing contracts under very unique context like Korean IT outsourcing projects. This study has some limitations in generalization because the sample size is small and the context itself is confined in an unique environment. For future exploration, survey based research could be designed and implemented.

• 한국인터넷방송통신학회논문지
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• 제13권4호
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• pp.229-237
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• 2013

최근 SOA와 클라우드 컴퓨팅 기반의 IT 서비스에 대한 수요가 증가하면서 서비스 당사자들 간에 SLA(Service Level Agreement, 서비스 수준 협약)에 대한 관심이 증대되고 있다. 통상 SLA는 자연어로 작성된 종이 계약서이다. 상업용 SLA 관리 툴에서 사용하는 SLA는 절차적 언어를 사용하여 계약서 내용을 애플리케이션 안에 암시적으로 구현된다. 이는 SLA 자동화 작업을 어렵게 한다. 또한 계약시스템에 대한 유지관리를 어렵게 하고 새로운 계약 요구사항을 적용하기 위해서는 소스 코드에 대한 광범위한 수정 작업이 뒤따른다. SLA 유지관리 과정에서 발생하는 문제의 근본 원인은 동일한 SLA가 문서형과 실행형으로 이원화 되어 있다는 것이다. 본 논문에서는 이러한 현행 SLA 관리의 문제점을 개선하기 위해서 능동형 SLA(ASLA : Active Service Level Agreement)를 기반으로 하는 능동형 SLM(ASLM : Active Service Level Management) 시스템을 제안한다. 이 시스템에서는 이원화된 SLA 처리 및 관리 과정이 능동형 SLA(ASLA)의 도입으로 일원화될 수 있음을 보였다.

• 한국연소학회지
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• 제15권4호
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• pp.15-21
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• 2010

The transported probability density function(PDF) model has been applied to simulate the turbulent nonpremixed piloted jet flame. To realistically account for the mixture fraction PDF informations on the turbulent non-premixed jet flame, the present Lagrangian PDF transport approach is based on the joint velocity-composition-turbulence frequency PDF formulation. The fluctuating velocity of stochastic fields is modeled by simplified Langevin model(SLM), turbulence frequency of stochastic fields is modeled by Jayesh-Pope model and effects of molecular diffusion are represented by the interaction by exchange with the mean (IEM) mixing model. To validate the present approach, the numerical results obtained by the joint velocity-composition-turbulence frequency PDF model are compared with experimental data in terms of the unconditional and conditional means of mixture fraction, temperature and species and PDFs.

• 한국분말재료학회지
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• 제24권3호
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• pp.202-209
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• 2017

A cold-work tool steel powder is used to fabricate 3-dimensional objects by selective laser melting using a high-pressure gas atomization process. The spherical powder particles form continuous carbide networks among the austenite matrix and its decomposition products. The carbides comprise Nb-rich MC and Mo-rich $M_2C$. In the SLM process, the process parameters such as the laser power (90 W), layer thickness ($25{\mu}m$), and hatch spacing ($80{\mu}m$) are kept fixed, while the scan speed is changed from 50 mm/s to 4000 mm/s. At a low scan speed of 50 mm/s, spherical cavities develop due to over melting, while they are substantially reduced on increasing the speed to 2000 mm/s. The carbide network spacing decreases with increasing speed. At an excessively high speed of 4000 mm/s, long and irregularly shaped cavities are developed due to incomplete melting. The influence of the scan pattern is examined, for which $1{\times}1 mm^2$ blocks constituting a processing layer are irradiated in a random sequence. This island-type pattern exhibits the same effect as that of a low scan speed. Post processing of an object using hot isostatic pressing leads to a great reduction in the porosity but causes coarsening of the microstructure.