• Journal of Communications and Networks
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• v.10 no.1
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• pp.79-88
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• 2008

In this paper, we propose efficient peer assignment algorithms for low-latency transmission of scalable coded images in peer-to-peer networks, in which peers may dynamically join and leave the networks. The objective of our algorithm is to minimize the transmission time of a requested image that is scalable coded. When an image is scalable coded in different bit rates, the bit stream encoded in a lower bit rate is a prefix subset of the one encoded in a higher bit rate. Therefore, a peer with the same requested image coded in any bit rate, even when it is different from the requested rate, may work as a supplying peer. As a result, when a scalable coded image is requested, more supplying peers can be found in peer-to-peer networks to help with the transfer. However, the set of supplying peers is not static during transmission, as the peers in this set may leave the network or finish their transmission at different times. The proposed peer assignment algorithms have taken into account the above constraints. In this paper, we first prove the existence of an optimal peer assignment solution for a simple identity permutation function, and then formulate peer assignment with this identity permutation as a mixed-integer programming problem. Next, we discuss how to address the problem of dynamic peer departures during image transmission. Finally, we carry out experiments to evaluate the performance of proposed peer assignment algorithms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.547-548
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• 2021

In this paper, we consider inner inheritance of parent objects to their child objects in SR DEVS. The inheritance process of function is implemented by the inside inheritance function when the inherited parent object is determined. In the inside inheritance, the integrity and fragment inheritance can be divided as th asset property. Also, the function process is requested when the inheritance selection in th inheritance is occurred to several assets. The child object can receive assets from the parent object through the determination method of selection function to the inside inheritance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1144-1152
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• 2000

In order to guarantee the user-requested quality-of-service(QoS) and keep the network utilization at maximum it is required to manage the network performance continuously after the network installation. The performance management function should provide the useful information for the network expansion and the capacity reallocation in the future. Currently the TINA provides the specification of the management function of configuration management connection management and fault management ; but the management function of performance management and security management are not well-defined yet. In this paper we propose a TINA-based performance management architecture for the efficient performance management of the heterogeneous networks or NEs with TMN and SNMP management functions. And we examine the proposed architecture into the ATM network (with SNMP and TMN) monitoring. The proposed architecture is based on the distributed processing architecture and the concept the TMN perfo mance management. The proposed architecture have been designed and implemented in multiprocess and multithread structure.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.158-165
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• 2019

The existing web page was downloaded and provided to the user every time the user requested the page. Therefore, if the same page is repeatedly requested by the user, only the download for the same resource is repeated. This is a factor that causes unnecessary consumption of data. We focus on reducing data consumption caused by unnecessary requests between users and servers, and improving content delivery speed. Therefore, in this paper, we propose a caching system and an algorithm that can reduce the data consumption while maintaining the latest cache by comparing the hash value using the hash function that can detect the change of the file requested by the user.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.203-211
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• 2009

In the area of the telecommunication industry, a few products have been developed before related technical regulation has been made. Government agency is forced to make a final decision on whether a requested product is sellable in the market only after the structure and function of requested product is tested. The introduction of a 'SDoC', and 'privatization of technical regulation' to our legal system could be a solution for minimizing the situation mentioned above. Both 'SDoC' and 'privatization of technical regulation' are systems which are capable of minimizing the appearance of products without technical regulations. Furthermore, 'Temporary approval system' would provide a government agency with administrative procedure for new product without technical regulation.

• Korean Journal of Construction Engineering and Management
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• v.5 no.3 s.19
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• pp.88-96
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• 2004

Recently, client requirements concept is an important issue related to many effects of firms. Especially, if we think that apartment is given a great deal of national construction industry, it is requested that we should try to improve apartment quality with various methods of client requirements survey and reflecting those on apartment project. The technique searching and applying client requirements to apartment project is requested for that and ROQ(Return On Quality) process connected to QFD(Quality Function Deployment) is a technique which is used in manufacturing industry and help to make money by rising client satisfaction with searching clients requirements, and applying this to quality improvement program. In this study apartment quality management development is suggested through using ROQ process. For this customer interview research and FGI(Focus Group Interview) was carried out and clients requirement was analyzed with this. Then quality improvement program applicable to developing a new apartment product was established with specialist monitoring. A new apartment quality management development plan is prosed with this process.

• Journal of the Ergonomics Society of Korea
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• v.28 no.4
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• pp.51-59
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• 2009

These days mobile phone which were used mainly by grown-up persons are now widely used among children as well due to new social demands. Despite this trend, existing mobile phones are still being designed and produced according to the taste of people in their 20s and 30s, even the elderly, not satisfying physical, emotional and cognitive characteristics raised by children. This study aimed to extract the design factors of mobile phones for children by reflecting functional factors requested by children and parents in QFD's customer demands. First, functional and design factors requested in mobile phones for children were extracted from existing products and documentary records and some functional factors were selected through a process of integration and omission. The survey research was conducted on children and parents, based on the selected functional factors. Based on the survey research, functional factors were analyzed using AHP, and key functional factors considered by children and parents in mobile phones for children were investigated. Finally, in order to reflect the results in QFD, the correlation between functional factors and design factors was constructed as HOQ through experts' evaluation. The results showed that both children and parents recognized the basic functions such as telephoning, text messaging and phone directory as high priority functional factors, even though the relative importance was different between children and parents. Therefore, it is likely to satisfy the desires of both children and parents by designing mobile phones for children in consideration of design factors such as menu depth, button independence and button arrangement. It is expected that this study will promote experiments on design factors and propose basic data for and guidelines to mobile phone design for children.

• KCID journal
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• v.18 no.2
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• pp.142-160
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• 2011

This study was performed to apply the preventive management technique that is known for more economic and preventive for disaster than corrective technique to Repair & Improvement(R&I) Project policy of irrigational facilities. The appropriate periods of R&I Project had been driven to 40yrs, 24yrs, 27yrs, and 29yrs for reservoir, Pumping and drainage pumping station, Diversion weir and Irrigation & drainage canal respectively. The cost of R&I Project for 10 years had been estimated as 616.9 billion won per year including the 85 billion won for the project of 'Disaster prevention and Function continuity'. After the period of 'Improvement all at once', about 30yrs, 421.8 billion won was requested for 'Function continuity'.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.735-736
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• 2008

There are many equipments for the Short Circuit Test, for example Short Circuit Generator, Induction Motor, Sequence Timer, CLR, Back Up Breaker, Making Switch and Excitation Equipment etc. Gradually an allowable tolerance of the short circuit test voltage is become smaller by the standards for short circuit test. The excitation equipment of short circuit generator is very important for test voltage is adjusted by the excitation equipment. Especially the excitation equipment must be possessed character of exactitude, durability and inalterability because some times around 10,000 times opening and closing short circuit test is requested by clint, which must be done within one minute. The purpose of this study for function and operation of the excitation equipment which rated DC voltage is 1,000V, rated DC current is 300A, rated out put is 30kW and type is YNEX 97S-441/609, is to help operation of short circuit generator.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.64.1-64.1
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• 2013

The point spread function (PSF) of an optical system is in general defined as a two-dimensional intensity distribution which results from a single point source at infinity. It is an important key for the evaluation of the optical performance of an astronomical telescope. The PSFs of the soft X-ray telescope (SXT) aboard Yohkoh were measured in a wide range of the field-of-view under the in-flight configuration at White Sands Missile Range prior to launching the satellite. It has been known that the SXT PSF has a sharp peak at the core and the intensity drops very fast as it goes distant from the center. Due to the combination of this sharp peak at the PSF core and the effect of undersampling by a large pixel size, a carefully designed method is requested in the examination of the PSF data. The pattern of the SXT PSF is determined by the fitting of a mathematical functional form to the pre-launch experimental data. The elliptical Moffat function has been adopted for the evaluation of the SXT PSF. It is revealed from our study that the SXT PSF shows a peculiar characteristics, and thus a careful consideration on the undersampling effect and also a proper choice of statistics are necessary for the determination of the best fit function of the PSF. Details on the on- and off-axis SXT PSF in the field-of-view will be introduced and discussed in our presentation.