• Plant Journal
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• v.17 no.2
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• pp.42-47
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• 2021

In terms of district heating operation, efficient production and supply of heat by alleviating the peak load at a specific time require an application technology that can solve the inconvenience of the user and the difficulties of the supplier. In this study, a 78 ℃ class PCM heat storage tank suitable among the technologies that can solve these problems was manufactured and applied to the hot water supply facility for apartments in district heating users. As a result of the application of this system, it was confirmed that the supply temperature was constant to the user compared to the existing supply method. In addition, it was confirmed that the reduction of the peak load due to load equalization reduced the heat supply margin of 10% in the existing heat supply facility. And the construction cost of the new heat supply facility and the construction cost of heat users is decreased by 5% and 10%, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.390-398
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• 2020

To solve the problem of frequent component failure in guided weapons, a process of component failure in developed countries was investigated and analyzed. The suitability of component control, including risk assessment, analysis of operational impact, and the establishment of response measures, was also demonstrated. In addition, the economic effects of component control were presented by estimating the costs incurred if component control is performed in advance, after-sales, and non-management. DMSMS problems refer to losses or impending losses of an item, raw material, or software manufacturer or supplier. A problem with the discontinuation of parts occurs when the manufacturer or supplier ceases to produce and support the necessary parts, materials, or software, or when the supply of raw materials is no longer possible. Hence, it is important to recognize that failure to all parts of the system can occur.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.157-168
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• 2009

The random utility theory and the multinomial logit model (including a more recent variant--the mixed multinomial logit) derived from it have constituted a back bone for theoretical and empirical analyses of various travel demand features including mode choice. In their empirical applications, however, it is customary to specify random utilities which are linear in modal attributes such as time and cost, and in socio-economic variables. The linearity helps easy derivation of important information such as value of travel time savings by calculating marginal rate of substitution between time and cost. In this paper the author focuses on the very linearity of the random utilities. Taking into account the fact that the mode chooser is also labour supplier, commodity consumer as well as leisure-seeker, the author sets up a maximization model of the traveller, which encompasses various economic activities of the traveller. The author derive from the model the indifference curve defined on the space of modal attributes, time and cost and investigate under what conditions the random utility of the traveller becomes linear. It turns out that there exist the conditions under which the random utility is really linear in modal attributes, but the property does not hold when the traveller has a corner solution on the space of modal attributes, or when the primary utility function of the traveller is directly affected by labour provided and/or the travel time itself. As a corollary of the analysis, a random utility is suggested, approximated up to the second order of the variables involved for empirical studies of the field.

• Journal of Construction Engineering and Project Management
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• v.5 no.3
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• pp.10-17
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• 2015

Consultant and owner play a very important role in the construction sector which is one of the main sectors in economic development. There are many stakeholders in a construction project including but not limited to: owner, consultant, contractor, subcontractor, and supplier. The consultant is the party who is to stay in close touch with the project owner, which both consultant and owner are considered as the main key stakeholders to make the project happen. It's not a simple task for a consultant to just implement the same style of management and control within various projects that are of a different background and character of owners. Thus, the adjusting plan management and control to the owner environment has been an essential technique to drive the project to success. The objective of this paper is to identify the significant management techniques for adjusting a plan of management and control to the owner environment in Thailand. The methodology is the identification throughout the analogous to abduction from literature review and our empirical observations of Future Engineering Consultants Co, Ltd. We have been in consultation for twenty-five years (25) in Thailand with 209 projects from both public and private owners. As a result, there are (1) Project management styles, (2) Personal style, (3) Owner expectation management, (4) Scope Management, (5) Time Management, (6) Cost Management, (7) Quality Management, and (8) Environmental Management. The input are: a clear defined goal, showing respect by giving good service, maintaining high quality, keeping in touch with owners, and resources. This would give the output of the project's success by meeting the owner's expectation and requirements.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1305-1317
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• 2015

Distributed generation systems (DGSs) have been getting more and more attention in terms of renewable energy use and new generation technologies in the past decades. The self-excited induction generator (SEIG) occupies an important role in the area of energy conversion due to its low cost, robustness and simple control. Unlike synchronous generators, the SEIG has to absorb capacitive reactive power from the outer device aiming to stabilize the terminal voltage at load changes. This paper presents a novel static VAR compensator (SVC) called a magnetic energy recovery switch (MERS) to serve as a voltage controller in SEIG powered DGSs. In addition, many small scale SEIGs, instead of a single large one, are applied and devoted to promote the generation efficiency. To begin with, an expandable mathematic model based on a d-q equivalent circuit is created for parallel SEIGs. The control method of the MERS is further improved with the objective of broadening its operating range and restraining current harmonics by parameter optimization. A hybrid control strategy is developed by taking both of the stand-alone and grid-connected modes into consideration. Then simulation and experiments are carried out in the case of single and double SEIG(s) generation. Finally, the measurement results verify that the proposed DGS with SVC-MERS achieves a better stability and higher feasibility. The major advantages of the mentioned variable reactive power supplier, when compared to the STATCOM, include the adoption of a small DC capacitor, line frequency switching, simple control and less loss.

• Transactions of the KSME C: Technology and Education
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• v.4 no.2
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• pp.123-130
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• 2016

Unitex is widely used for the floor structure of urban railway vehicles because it shows good structural safety and heat insulation, has long life, and lowers the cost owing to easy installation. However, in spite of these merits, Unitex has a limit to the sound insulation performance, which is very important in vehicle structure. It shows a sound transmission loss considerably lower than the mass law value, which indicates the sound insulation performance per unit weight. Recently, railway vehicle manufacturers and Unitex supplier have tried to improve the sound insulation performance of Unitex, but meaningful results have not been achieved yet. Through the industry-university collaborative research, we propose structural improvement methods to increase the sound transmission loss by more than 5dB and we then verify the effect by performing experiments.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.54-63
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• 2010

Recently, as the function of largest supplier of biomass for "low carbon green growth", the necessity for systematic management of afforestation areas is emphasizing. The forestation of seedling, besides the afforestation cost itself, is required some additional follow-up management costs, like mowing and fertilizing of forestation area, and removal of bindweed. The mulching mat for afforestation seedlings is available for rooting of little seedlings as well as initial forestation expenses. Mulching technique is also used to control soil temperature and moisture by covering the surface of ground. In this study, the paper based-mulching film coated with biodegradable polymer and functional additive was specially produced using laboratory bar coater, and analyzed for its degradable behavior. Coating colors were prepared by dissolving PE (polyester) 80 % and PLA(polylactic acid) 20 % in chloroform and finally applied to handsheet prepared by preceding study conditions. Base paper and polymer-coated paper were artificially aged by 2 kinds of degradation methods, which are soil degradation by microorganism and light degradation by 257 nm UV wavelengths. Strength property, oxidation index and morphological property were evaluated by reduction rates of tensile strength, FTIR spectra ratio of carboxyl and carbonyl group and SEM micrograph. As these results, polymer coated-paper was superior to base paper in degradation behaviors, having results with lower reduction rate of strength properties.

• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1496-1504
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• 2004

Web service should be to connect business between enterprise through the Internet, promotion of construction speed and decrease of development expense of service construction are possible. Also, unification with other domain is possible easily, and update or correction is easy by offering reusability and replaceability through component based development. In this paper, We suggest development process to build architecture and this to integrate consisted component efficiently to develop web service that is embodied in supplier side on service oriented architecture(SOA). The suggest architecture to integrate component that is consisted for this efficiently, and describes development process. So that component develops web service to base structure of web service because do command stratification logically function in each hierarchy define, and presents architecture based on logical hierarchy. The web services consist of Facade and Backside component; The Facade component have web service functions. We describe process that develop to Facade component and present mailing web services as case study. It can be decrease production cost and development time. The web service based on component will improve reliability for reuseability and replaceability.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.4 s.22
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• pp.51-60
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• 2002

As the use of GIS becomes more widespread, the quality and source of data is becoming more of a concern among users. But accuracy is a component of quality, and the positional accuracy is a component of total accuracy. If only we consider the positional accuracy, simultaneously collecting technology of location and attribute information, whether it be manually, using conventional surveying method, GPS, or remote sensing, is a practical way of insuring that location and attribute information are correctly correlated. This study analyse the positional accuracy from a view-point of user and supplier, which is the considerations that can ensure quality level and continuously maintain the road and underground utility information. The positional accuracy of road and underground utility information are considered as two categories - expected accuracy of data collection procedure, required accuracy of data usage process. And the project manager must consider the cost/benefit view of data generation in order to determine the surveying method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.125-130
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• 2013

According to the law revision of TPMS mounting obligations in Korea, researches about energy harvester which is the alternative of the battery are actively performed by many groups. Because WSN (Wireless Sensor Network) has the proposition of "Install and forget" and the power supplier also has the same performance as the vehicle's lifetime. In this paper, electromagnetic induction type of energy harvester through the relative motion between the rotating wheel and the fixed brake disc is introduced by using the most efficient source as the rotating motion in the view of vehicle's mechanism. The coil on the wheel and the permanent magnet at the brake disc are arranged in several ways. These various arrangements are the number of coil turns are consisted of design variables. By using the orthogonal array to reduce the experimental cost, the optimal composition is verified through the experiment. Finally the validity of the module is considered by measuring the level of storable electrical energy.