• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.300-306
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• 2020

This study analyzes the distributor's inventory model in a two-stage supply chain consisting of the supplier, the distributor and the end customer. The supplier will allow a credit period before the distributor settles the account with him in order to stimulate the demand for the product he produces. It is also assumed that the distributor pays the shipping cost for the order and hence, the distributor's ordering cost consists of a fixed ordering cost and the shipping cost that depend on the order quantity. The availability of the delay in payments from the supplier enables discount of the distributor's selling price from a wider range of the price option in anticipation of increased customer's demand. As a result, the availability of a credit transaction leads to an increase in inventory levels. On the other hand, in the case of deteriorating products in which the utility of the product perish over time, the deterioration rate with time plays a role in reducing inventory levels. In this regard, we analyze the effect of the length of the credit period and the degree of product deterioration on the distributor's inventory level. For the analysis, we formulate the distributor's annual net profit and analyze the effect of the length of credit period and deterioration rate of the product on inventory policy numerically.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.04a
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• pp.35-35
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• 1997

High$\cdot$speed steels (HSS) with a combination of good wear resistance and toughness are finding new, non-cutting applications such as rolls and rollers. In this paper, the research interests are focused on the microstructural evolution of a SMo-6W series high speed steel during HIPping and the effect of HIPping process parameters on its microstructure and properties. HIPping process variables includes; temperature, pressure and hold time. The microstructures of the HIPped HSS were examined by SEM, OM and X-ray diffraction whereas the properties measured were the relative density, hardness, and bend strength at room temperature. In HIPped materials, MC and M6C were the major carbides formed in a matrix of martensite. The effect of powder size on the microstructure and mechanical properties of HIPped materials was insignificant. However, HIPping temperature and hold time strongly affected the carbide size and distribution. The results show that at proper HIPping temperature and pressure conditions, the final products approach the full density ( > 99% RD). The particle boundaries were completely eliminated without an eminent microstructural coarsening. The bend strength was about 2.3 Gpa, which is superior to cast HSS. At excessive HIPping temperatures, rapid carbide coarsening occurred, thus deteriorating the mechanical properties of the P/M steels.

• Journal of Power Electronics
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• v.19 no.2
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• pp.580-590
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• 2019

The concept of virtual synchronous generators (VSGs) is a valuable means for improving the frequency stability of microgrids (MGs). However, a great virtual inertia in a VSG's controller may cause power oscillation, thereby deteriorating system stability. In this study, a small-signal model of an MG with two paralleled VSGs is established, and a control strategy for maintaining a constant inertial time with an increasing active-frequency droop coefficient (m) is proposed on the basis of a root locus analysis. The power oscillation is suppressed by adjusting virtual synchronous reactance, damping coefficient, and load frequency coefficient under the same inertial time constant. In addition, the dynamic load distribution is sensitive to the controller parameters, especially under the parallel operation of VSGs with different capacities. Therefore, an active power increment method is introduced to improve the precision of active power sharing in dynamic response. Simulation and experimental is used to verify the theoretical analysis findings.

• Steel and Composite Structures
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• v.29 no.1
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• pp.107-123
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• 2018

The conception and experimental assessment of a removable friction-based shear connector (FBSC) for precast steel-concrete composite bridges is presented. The FBSC uses pre-tensioned high-strength steel bolts that pass through countersunk holes drilled on the top flange of the steel beam. Pre-tensioning of the bolts provides the FBSC with significant frictional resistance that essentially prevents relative slip displacement of the concrete slab with respect to the steel beam under service loading. The countersunk holes are grouted to prevent sudden slip of the FBSC when friction resistance is exceeded. Moreover, the FBSC promotes accelerated bridge construction by fully exploiting prefabrication, does not raise issues relevant to precast construction tolerances, and allows rapid bridge disassembly to drastically reduce the time needed to replace any deteriorating structural component (e.g., the bridge deck). A series of 11 push-out tests highlight why the novel structural details of the FBSC result in superior shear load-slip displacement behavior compared to welded shear studs. The paper also quantifies the effects of bolt diameter and bolt preload and presents a design equation to predict the shear resistance of the FBSC.

• Journal of Computing Science and Engineering
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• v.2 no.2
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• pp.180-199
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• 2008

Technology has had a tremendous impact on our daily lives. Recently, technology and its impact on aging has become an expanding field of inquiry. A major reason for this interest is that the use of technology can help older people who experience deteriorating health to live independently. In this paper we give a brief review of the in-home monitoring technologies for the elderly. In the pilot study, we analyze the possibility of employing the data generated by a continuous, unobtrusive nursing home monitoring system for predicting elevated(abnormal)pulse pressure(PP) in elderly(PP=systolic blood pressure-diastolic blood pressure). Our sensor data capture external information(behavioral) about the resident that is subsequently reflected in the predicted PP. By continuously predicting the possibility of elevated pulse pressure we may alert the nursing staff when some predefined threshold is exceeded. This approach may provide additional blood pressure monitoring for the elderly persons susceptible to blood pressure variations during the time between two nursing visits. We conducted a retrospective pilot study on two residents of the TigerPlace aging in place facility with age over 70, that had blood pressure measured between 100 and 300 times during a period of two years. The pilot study suggested that abnormal pulse pressure can be reasonably well estimated (an area under ROC curve of about 0.75) using apartment bed and motion sensors.

• Journal of Korean Medical classics
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• v.21 no.4
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• pp.179-191
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• 2008

Yuchang(喩昌), prominent doctor in the early days of Cheong Dynasty, argued in favor of Daegiron(大氣論) and Chujoron(秋燥論). He referred the concept of Daegi(大氣) to the initiatory force that maintains and perpetuates the vital activities of human body. The historical background of his argument can be related to the abuses of the doctrine of warming and tonifying. At that time, the practice of misusing warming and tonifying herbal medicines without deteriorations of a case was widespread among doctors. Dryness and heat disease mechanism was triggered from this malpractice. Subsequently Yuchang(喩昌) witnessed many cases of lung diseases resulting from dryness and heat. That's why he suggested relieving dryness of the lung as a treatment, further establishing Daegi(大氣) - which correlates with the lung - as the vital fundamentals. Yuchang(喩昌)'s argues that the autumn energy emanates after the Autumn Equinox and that is what Chujo(秋燥) signifies in Chujoron(秋燥論). He articulates that most of the autumn diseases can be attributed to fire and heat. This argument is distinguished from the one that attributes lung diseases to coldness, thus providing an important factor in deteriorating a lung disease.

• Journal of the military operations research society of Korea
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• v.17 no.1
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• pp.61-83
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• 1991

There has been a great deal of research dealing with the optimal replacement of stochastically deteriorating equipment and research in queueing systems with a finite calling population. However. there has been a lack of research which combines these two areas to deal with optimal replacement for a fixed number of machines and a limited number of repairmen. In this research, an optimal control policy for replacement involving two machines and one repairman is developed by investigating a class of age replacement policies in the context of controlling a G/M/1 queueing system with a finite calling population. The control policy to be imposed on this problem is an age-dependent control policy, described by the control limit $t^{\ast}$. The control limit is operational only when the repairman is idle; that is. if both machines are working, as soon as a machine reaches the age $t^{\ast}$ it is taken out of service for replacememt. We obtain the ${\epsilon}$-optimal control age which will minimize the long-run average system cost. An algorithm is developed that is applicable to general failure time distributions and cost functions. The algorithm does not require the condition of unimodality for implementation.

• Journal of architectural history
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• v.10 no.2 s.26
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• pp.35-54
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• 2001

This study concerns especially Choryang-Weagwan which was the largest Japanese House left in Pusan through Chosun Dynasty. Choryang-Waegwan was known to have been jointly constructed by Korean and Japanese carpenters. Therefore, Weagwan was a place for exchange of architectural tradition (special features such as sliding door and straw mat) between Korean and Japan. Judging from this point of view, It is certain that mutual influences helped to shape architecture of Choryang-Weagwan. After establishment Choryang- Weagwan was gradually extended, owing to the prosperity of trade with Japan. But since late 18th century government of Chosun did not give as much care to maintaining Choryang- Weagwan as a result of deteriorating condition of commercial and diplomatic relations with Japan. From the beginning of Choryang- Weagwan construction, Superintendents of the construction were called Hun-do and Byl-cha, who acted as official interpreters as well. And, during construction works, they were called Gamdong-gwan, At the start of construction, Weagwan was built partly in Japanese-style by the carpenters from Tokugawa Shogunate. But as time passed, the participation rate of Japanese carpenters diminished gradually. After 1831, Japanese technician vanished extremely and repairing construction was continued by the Korean workers only.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1177-1190
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• 2010

The high-speed railway track occurs train operating result track irregularity, subsidence of the track, ballast abrasion. This is the unusual condition. High-speed railway track maintenance task is the behavior which repairs unusual section by using the human resource or machine resource. The resource used to maintenance task is restrictive. A resource can be efficiently used if the high-speed railway track maintenance scheduling is used. So the more task can be performed in the fit time. In conclusion, this manages the unusual condition of a track efficiently. So additional expenses is minimized cause by deteriorating unusual condition. And it offers comfortable ride to passenger. However, maintenance scheduling has to reflect well practical situation and environment. That's maintenance scheduling is used. We gather the opinions of the hands-on workers. So in this paper define field situation and condition. And suggest mathematical model about this. And we developed the track maintenance scheduling software engine using ILOG.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.285-290
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• 2008

Recently, the scale of the construction work has been increased due to the revitalization of the construction industries. therefore, the demolition work in downtown areas is increased too. Amelioration districts are deteriorating rapidly since it followed the policy which allowed a large number of constructions in a very short period of time. therefore, the quantity of construction wastes and the designated wastes such as asbestos are increased. This study was classifying and analyzing the constructions in amelioration districts to estimate quantity of the designated wastes and the unit of the designated wastes. According to the results of this research, the average annual designated wastes was increased up to 2.59% in comparison with 2,779,334 ton in 2000, there came out 3,151,653 ton of designated wastes in 2005. For the appropriate disposal of increasing designated wastes, it is necessary to study exact estimation of the quantity of wastes.