• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.2
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• pp.20-25
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• 2010

A camera module is supported by a gimbal structure in collection equipment of image information. During flight, the gimbal system undergoes serious accelerations with wide frequencies. To get the correct images, the camera module must be stably vibrated under these conditions. If natural frequency unfortunately exists in a exciting frequency range, resonance occurs there. Hence, harmonic responses analysis is needed to know correct vibration characteristic of the gimbal system. Finite element analysis was performed to get an acceleration of the gimbal system by mode superposition after extracting mode shapes and natural frequencies. Considering damping ratio of 2%, the reponses of gimbal structure were calculated from excitations with a design frequency band. As results, a maximum acceleration transmissibility, which is the ratio of response to excitation, was obtained and it can be used to design the gimbal structure effectively.

• Journal of the Korean Society for Library and Information Science
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• v.15
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• pp.175-195
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• 1988

Use studies of library collections have been conducted as a method of evaluating collections in a library. The main purpose of use studies is to evaluate the quality of a library collection in terms of extent and mode of its use. In addition to use studies, both quantitative and qualitative methods could be utilized in order to evaluate a library collection. However, the quantitative and qualitative collection evaluation methods are more concerned with the collection itself than with its use. Use studies have been conducted in large academic libraries for the following specific purposes: 1) They attempt to identify little used portion of collections that can be retired less accessible and less expensive storage area. 2) They try to identify core collections to satisfy some degree of circulation demands in the near future. 3) They try to identify use patterns of selected subject areas or type of books that can be used to adjusting collection development practices or fund allocations. 4) They try to assess the document delivery capability of a library to improve their availability. A number of methodologies employed for these specific purposes fall into four major categories; 1) circulation analysis method, 2) last circulation method, 3) relative use method, and 4) document delivery test. Each method is briefly reviewed with its limitations.

• Journal of Environmental Science International
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• v.10 no.5
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• pp.351-358
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• 2001

The main purpose of this study was to investigate the characteristics of cylindrical electrostatic precipitator with centrifugal effect in viewpoints of pressure drip and collection efficiency, experimentally. The experiment was carried out for the analysis of current-voltage, pressure drop and collection efficiency with various experimental parameters such as the applied voltage, inlet velocity, inlet size and inlet type(upper and bottom), etc. In the results, the pressure drops were estimated as 27~54, $34~63mmH_2O$ for inlet size $15mm{\tiems}30mm$ and $30mm{\tiems}60mm$, respectively. The collection effeciencies were shown over 90% with the small inlet size($15mm{\tiems}30mm$) for the applied voltage 40kV, inlet velocity(15~21m/s), and 51~89% with the large inlet size ($30mm{\tiems}60mm$). Moreover, in the applied voltage 0kV and inlet size $15mm{\tiems}30mm$, the collection efficiency induced by centrifugal force was represented as about 35% with inlet velocity 15 - 21m/s.

• Industrial Engineering and Management Systems
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• v.14 no.3
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• pp.248-274
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• 2015

This study discusses a contract to promote collection and recycling of used products in a green supply chain (GSC). A collection incentive contract is combined with a reward-penalty contract. The collection incentive contract for used products is made between a retailer and a manufacturer. The reward-penalty contract for recycling used products is made between a manufacturer and an external institution. A retailer pays an incentive for collecting used products from customers and delivers them to a manufacturer with a product order quantity under uncertainty in product demand. A manufacturer remanufactures products using recyclable parts with acceptable quality levels and covers a part of the retailer's incentive from the recycled parts by sharing the reward from an external institution. Product demand information is assumed as (i) the distribution is known (ii) mean and variance are known. Besides, the optimal decisions for product quantity, collection incentive of used products and lower limit of quality level for recyclable parts under decentralized integrated GSCs. The analysis numerically investigates how (1) contract for recycling activity, (ii) product demand information and (iii) quality of recyclable parts affect the optimal operation for each GSC. Supply chain coordination to shift IGSC is discussed by adopting Nash Bargaining solution.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.2
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• pp.53-77
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• 2020

This study was carried to analyze the current status of oral history collections of national libraries in foreign countries and to derive key factors to consider when building oral collections in National Library of Korea(NLK). The Library of Congress, the British Library, and the National Library of Australia regard oral records as a national heritage that should be passed down nationally and those have been utilized and preserved successfully. Based upon the analysis of the oral collections of these national libraries, several key elements - legislation, organization, collection policy, services, collection, education and collaboration, funding and sponsorship-to consider when building an oral history collection for the first time in the NLK were suggested.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.29 no.4
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• pp.251-267
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• 2018

In this research, a sample was selected from a public library in Paju city, which operates a regional collaborative library system. They collected data on materials, usage, and acquisition. An analysis of book collection data and usage data was also conducted in order to evaluate the correlation between the usage and acquisition by comparing overlap of purchased materials. As a result, circulations and the interlibrary loan (ILL) borrowing requests were differentiated by topics according to targeted materials, and that these characteristics affect the overlap of purchased materials. The study suggested that public libraries in the region collaborative library system need to consider the paradigm of collection and access when purchasing books.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.20 no.1
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• pp.151-164
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• 2009

This study attempted to analyse the collections of public libraries in terms of their subject distribution and currency. It was expected that the analysis would give public librarians some suggestions as to their collection development policy making. This study team selected 423 Korean public libraries across the country and scrutinized the collections by their classes of Korean Decimal Classification(KDC) and publishing years. The study results indicated that there was some subject disproportion in public library collections. Literature and social sciences were accounting for 54.8% of whole collections. Currency of collections of public libraries could be said relatively excellent. It was found that 64.9% of whole collections had been published after 2000.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.242-250
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• 2022

Here we aimed to date the year and season of the resin collection from Korean red pines at Worak mountain and investigate the natural healing ability of the wounds using the tree-ring analysis technique. We determined the dating of the resin collection based on the synchronization between the ring-width time series from the wound surface of the experimental trees and the local master chronology, which is the mean time series from the sound surface on the opposite side of the wounds. For the dating of resin collection, we selected thirteen Korean red pines with resin wounds. For the investigation on the annual healing ability of the wounds, we sampled three dead trees out of 13 trees as disks. Through the comparison of the individual ring-width time series from the wounds with the local master chronology, it was verified that the resin collection was undertaken between the spring of 1962 and the autumn of 1975. The mean healing length of the wounds was 15.8 cm over the preceding 42 years, making their annual mean healing 0.38 cm. Through our study we successfully verified the healing ability of the wounded Korean red pines for the resin collection as well as the undocumented resin collection history.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.422-428
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• 2009

NAND flash memory is widely used in embedded systems because of many attractive features, such as small size, light weight, low power consumption and fast access speed. However, it requires garbage collection, which includes erase operations. Erase operation is slower than other operations. Further, a block has a limited erase lifetime (typically 100,000) after which a block becomes unusable. The proposed garbage collection policy focuses on minimizing the total number of erase operations, the deviation value of each block and the garbage collection time. NAND flash memory consists of pages of three types, such as valid pages, invalid pages and free pages. In order to achieve above goals, we use a page ratio to decide when to do garbage collection and to select the target victimblock. Additionally, we implement allocating method and group management method. Simulation results show that the proposed policy performs better than Greedy or CAT with the maximum rate 85% of reduction in the deviation value of the erase operations and 6% reduction in garbage collection time.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.9
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• pp.617-625
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• 2009

NAND flash memory is widely used in embedded systems because of many attractive features, such as small size, light weight, low power consumption and fast access speed. However, it requires garbage collection, which includes erase operations. Erase operation is very slow. Besides, the number of the erase operations allowed to be carried out for each block is limited. The proposed garbage collection method focuses on minimizing the total number of erase operations, the deviation value of each block and the garbage collection time. NAND flash memory consists of pages of three types, such as valid pages, invalid pages and free pages. In order to achieve above goals, we use a page rate to decide when to do garbage collection and to select the target victim block. Additionally, We implement allocating method and group management method. Simulation results show that the proposed policy performs better than Greedy or CAT with the maximum rate at 82% of reduction in the deviation value of erase operation and 75% reduction in garbage collection time.