• Journal of the Korean Magnetics Society
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• v.23 no.2
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• pp.43-48
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• 2013

The Jahn-Teller distortion of chalcogenide $Fe_{0.9}M_{0.1}Cr_2S_4$ (M=Co, Ni, Zn) have been investigated by M$\ddot{o}$ssbauer spectroscopy. The crystal structures of $Fe_{0.9}M_{0.1}Cr_2S_4$ (M=Co, Ni, Zn) are cubic spinel at room temperature. Magnetoresistance measurements indicate these system is conducting-semiconducting transistion around $T_C$. Below $T_C$, the asymmetric line broadening is observed and considered to be dynamic Jahn-Teller distortion. Isomer shift value of the samples at room temperature was about 0.5 mm/s, which means that charge state of Fe ions is ferrous in character. The Ni substitutions for Fe occur to increase the Jahn-Teller relaxation. CMR properties could be explained with magnetic polaron due to Jahn-Teller effect, which is different from both the double exchange interactions of manganite system and the triple exchange interactions of chalcogenide $Cu_xFe_{1-x}Cr_2S_4$.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.509-512
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• 2007

In Domestic, the beginning of CM system was at December 1996 by 'Construction Industry fundamental law'. Today the needs of CM is more and more during 10 years. Although the time of CM's induction and high-quality human resources are insufficiency, various studies and developments's level through theoritical base and academic level is good which are compared by developed countries's. But still now the effort of CM product measure part, especially public sector is not enough. Besides, the existing check-list is for project owner so it needs to make up for balanced view as organized 4way-view of owner, CMr, designer, constructor. On this study, produce the list of check-list and then weight of each list by view of owner, CMr, designer, constructor. The completec check-list will be useful for CM product measure objectively .

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.194-205
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• 2008

The production process of construction industry is different from thing of the general manufacturing, likewise various participants make temporary teamwork for success of the project through sharing of information. But, the each role of participants is Individually changed to step in construction process stage and moreover it has complicated, entangled interests. The CM(so it called Construction Management as an abbreviation word) system was inducted for the effective management and operation of construction project. The key of the CM success depends on the cooperative relationship relation to major participants. There are lots of studies and efforts for the performance measures of the CM, however existing performance index is only measured as the viewpoint of project owner. Therefore it needs to make up for balanced view through combination of the four-way view of participants. In this study, we should search for cooperative relationship of project participants, and then we should suggest to define the difference of project in their viewpoints.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.1
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• pp.40-49
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• 2023

Objectives: The handling of carcinogenic, mutagenic or reproductive toxic (CMR) materials in paint-related products used by automobile maintenance companies in Busan was investigated and its characteristics were analyzed. Methods: MSDS for paint-related chemical products used by automobile repair companies in Busan were collected and the manufacturers, product uses, names of chemical substances in each component, CAS numbers, content, and more were listed. Results: As a result of collecting MSDS on 4,800 kinds of products handled in the painting process of automobile repair companies in Busan and comparing them with the latest toxic information database, 60 out of a total of 438 substances were found as CMR materials. Seven carcinogens (1A), including quartz, benzene, formaldehyde, and hexavalent chromium, were present. Two reproductive toxic 1A substances were included: hexavalent chromium in paint pigments and lead. Conclusions: Most of the products (95.5%) were found to contain at least of one CMR component, so it was judged that a study on exposure assessment of CMR substances by automobile maintenance workers is needed in the future.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.3
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• pp.342-350
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• 1999

Two location algorithm (TLA) considers two location areas (LAs) to track the location of a mobile station (MS). The TLA significantly outperforms the single location algorithm when the call-to-mobility ratio (CMR) is low (i.e., the user moves more frequently than to receive calls). However, because of the paging cost for the users moving back to the previously visited LA, the performance of the TLA degrades when the CMR is high. To reduce those paging cost, we propose the new algorithm called TLA with call information (TLAC). In TLAC, we use the location information of the MS within the setup message when the MS originates a call in the previously visited LA. Through the setup message, the system can know the exact location of the MS without the additional location registration operation, and the paging cost for the arriving calls in the visited LA can be reduced. An analytical model is proposed to compare the TLAC and previous TLA protocol. Our study indicates that the TLAC always guarantees better performance than the TLA. We also observe that the TLAC is much better than the TLA when the CMR is high.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.296-299
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• 2002

Construction Management tends to create a formal procurement resulted from recent legislative procedures system in domestic construction industry. However, the fact that construction Manager(CMr) has been chosen, in practice, under a poor circumstance in selecting and discriminating specialty requires the more optimal procedures. Therefore, in this research, we analyze the existing shortcomings. the various procedures, influence factors, and the criteria to be considered in selecting and evaluating CMr. Also. this study suggests the improved method based on the facts above. To accomplish the construction project successfully, it is one of the advanced schemes to choose an adequate CMr needed to the project through the precision in the formation and application of the procedure as well as the suggested criterion in selecting CM.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.674-681
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• 2012

With the rise in the functions required in modern building structures, the role of the building equipment that maintains the functions of a building has been emphasized and increased. Effective management in this area is only possible when the construction manager (CMr) is qualified and has the knowledge of building equipment that is needed. Therefore, in this study, a questionnaire survey was carried out on equipment engineers and CMrs, in order to determine the level of building equipment knowledge required, and to identify the perception level of CMrs about the building equipment in the construction project at the project design stage. The results of this study revealed that the CMrs surveyed had a lower level of knowledge on the building equipment than the level that was desired by the equipment engineers. This indicates that CMrs currently have a weak capacity for the management of building equipment. It is thus necessary for CMrs to undergo systematic training in order learn more about building equipment and thus be able to manage construction projects more efficiently.

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.551-557
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• 2001

La$_{0.7}$Ca$_{0.3}$MnO$_3$분말을 용액연소법으로 제조하였으며 분말 특성과 CMR에 응용하기 위해 박막의 전기적, 자기적 특성을 조사하였다. 조성과 구조 특성을 XRD와 SEM으로부터 조사하였으며 분말의 하소온도를 TG 분석으로부터 결정하였다. 또한 소결성은 dilatometer에 의해 조사되었으며 분말 특성은 BET에 의해 조사되었다. 소결성이 우수한 분말을 이용하여 스퍼터 타겟으로 제조하였으며 SiO$_2$/Si 기판 위에 스퍼터링한 후, 온도에 따른 four point probe 측정으로 막의 MR비를 측정하였다. VSM (Vibrating Sample Magnetometer)를 이용하여 증착된 막의 온도에 따른 자화율(Magnetization:M)을 측정하였다. 분말 특성으로는 평균입자 크기가 sub-micron 이하로 초미세하고 49.44$m^2$/g의 비표면적 값을 얻을 수 있었으며 고순도의 perovskite 구조를 갖는 La$_{0.7}$Ca$_{0.3}$MnO$_3$분말을 쉽게 얻을 수 있었다. 온도에 따른 저항값의 변화로부터 96K에서 최고의 MR값을 얻을 수 있었으며, 240K에서 강자성체로 전이되었다.로 전이되었다.

• Journal of Construction Engineering and Project Management
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• v.1 no.1
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• pp.1-10
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• 2011

This paper discusses the components of a guaranteed maximum price (GMP) and proposes a framework for the development of GMPs as contract payment provisions for construction manager-at-risk (CMR) and design-build (DB) contracts for transportation projects. The framework is the synthesis of a comprehensive literature review, a content analysis of CMR and DB solicitation documents and contracts, and case study project output from twelve projects in nine states worth $3.1 billion. The research also discusses the development of three common types of contingencies that are often utilized in projects with GMPs. The study concludes that owners should specify the structure of the GMP and its components to enhance clarity and understanding of the GMP's composition. It recommends that this structure be included in the CMR and DB solicitation documents so that pricing proposals can be formulated in a manner that is consistent with the contract payment provisions that will be useful to practitioners that need to implement GMP-based contracts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.361-361
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• 2007

A lot of efforts have been paid to develop infrared imaging systems in last decades. Bolometer has a wide range of applications from military to commercial, such as military night vision, medical imaging system and so on. Bolometer is a resistive sensor that detects temperature changes through resistance change. To improve detecting ability, bolometer should have a good resistive film which has high temperature coefficient of resistance (TCR) value. Colossal magnetoresistance (CMR) $L_{1-x}A_xMnO_3$ (where L and A are trivalent rare-earth ions and divalent alkaline earth ions, respectively.) are received attention to apply bolometer resistive film because it has a high TCR property which was discovered in the metal to semiconductor phase transition temperature region. In this work, CMR films were deposited on various substrates in relative low substrate temperature by RF magnetron sputtering. The influence of deposition parameters such as substrate temperature, gas partial pressure, and so on have been studied. The structural and TCR properties of the films were also investigated for applying to microbolometer.