• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.132-137
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• 1998

In this paper, conventional STM(Synchronous Transfer Mode) supports another traffics by using idle channels Proposed mobile terminals are distributed independently at the BSA(Basic Service Area). So, MAC(Medium Access Control) specified on the wireless ATM networks, which is managing statistics multiplexing functions, idle channel's utilization is maximized and multimedia service characteristic for conventional wired networks based fixed assignment scheme(connection-oriented) and random assignment scheme(connectionless) improving on dynamic reservation based MAC protocol.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2005.10a
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• pp.119-123
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• 2005

New paradigm of the 21st is 'Ubiquitous'. And great changes arises from the digital environment and technology. Also, our living environments are changing very rapidly. Because of rapid developments, we didn't have enough time to examine our current situation. So we had to look around the current living spaces. The main purpose of this research was to know about the home network service and environmental context in our living spaces and to explore the outlook in the forseeable future. To search them, four recent digital home exhibition houses were examined. The findings showed that many kinds of common network systems were suggested and were acted in limited spaces. And when we examined the environmental context, we found most of the instruments were installed fixed ones or integrated information appliances. Therefore, the plan of digital home needs to consider environmental context and the combination of residents and living spaces.

• Korean Journal of Mathematics
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• v.29 no.2
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• pp.371-386
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• 2021

This paper investigates two discrete time queueing inventory models with positive service time and lead time. Customers arrive according to a Bernoulli process and service time and lead time follow geometric distributions. The first model under discussion based on replenishment of order upto S policy where as the second model is based on order placement by a fixed quantity Q, where Q = S - s, whenever the inventory level falls to s. We analyse this queueing systems using the matrix geometric method and derive an explicit expression for the stability condition. We obtain the steady-state behaviour of these systems and several system performance measures. The influence of various parameters on the systems performance measures and comparison on the cost analysis are also discussed through numerical example.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1154-1164
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• 2010

As an useful application in broadcasting services, the targeting service has been mainly studied to improve the service satisfaction and user usage in various media service environments based on user profile, preferences, and usage history. Targeting service is expanding its domain from broadcasting contents to interstitial contents and from fixed TV devices to mobile devices. Service data also include advertisement data, coupon, and information about media contents as well as simple broadcasting data. In this paper, the targeting data service is designed and implemented on articles, advertisement and broadcasting information on the basis of the user information. To adapt this to web-based media contents, information on user profile, preferences, and usage history is newly defined on the basis of the user metadata developed in TV-Anytime Forum and the user information defined in OpenSocial. The targeting data service is implemented to generate user preferences information and usage history pattern based on the similarity among user preference, contents information, and usage history. Based on performance evaluation, we prove that the proposed targeting data service is effectively applicable to web-based media contents as well as broadcasting service.

• Korea Journal of Hospital Management
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• v.5 no.1
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• pp.200-231
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• 2000

The price systems of the hospital drug services play key roles in the provision of quality services and the development of pharmacy service technologies. Under the premises, this study attempted to determine the costs of hospital drug service, to compare the costs calculated with the fees publicly fixed by the Government, and based on the results of the analysis, to propose directions for the improvement of the price systems. A Costing model for the study was developed based on the cost-fee relationship analysed of the Korean fee-for-service systems. Data on costs and workloads of the 25 hospitals were collected through survey forms designed for the costing' and analysis for the duration of 12 months of 1998. The results of the analysis show that a tremendous unbalance between cost and price levels of the drug services, and that overally the price level of the services is extremely low when compared to the costs of services. Based on these findings, this study suggests that unfairly high or low price level be corrected, and that service items newly developed and being practiced at tertiary hospitals, such as TDM and TPN consultation services, be compensated by fixing a proper level of price.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6C
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• pp.615-623
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• 2003

This paper presents effective quality-of-service renegotiating schemes for streaming video. The conventional network supporting quality-of-service generally allows a negotiation at call setup. However, it is not efficient for the video application since the compressed video traffic is statistically non-stationary. Thus, we consider the network supporting quality-of-service renegotiations during the data transmission, and study effective quality-of-service renegotiating schemes for streaming video. Simple token bucket model, whose parameters are token filling rate and token bucket size, is adopted for the video traffic model. The renegotiating time instants and the parameters are determined by analyzing the statistical information of compressed video traffic. In this paper, two renegotiating approaches, i.e. fixed renegotiating interval case and variable renegotiating interval case, are examined. Finally, the experimental results are provided to show the performance of the proposed schemes.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.183-193
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• 2006

This paper suggests a service model which uses a wireless sensor network in home network environment. The sensor network consists of fixed sensor nodes and user identification nodes which is attached to each user. With the input information of the user preference profile and the collected data from the sensor nodes, the database is constructed as a context information and analyzed by a home server to provide a service that establishes and controls automatically home appliances according to each user's preference. The proposed service model is implemented and tested on a Linux server with MySQL database and sensor nodes on TinyOS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.4
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• pp.632-650
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• 2013

The paper considers a spectrum sharing cognitive radio (CR) network coexisting with a primary network under the average interference power constraint. In particular, the secondary user (SU) is assumed to carry delay-sensitive services and thus shall satisfy a given delay quality-of-service (QoS) constraint. The secondary receiver is also assumed to be equipped with multiple antennas to perform maximal ratio combining (MRC) to enhance SU performance. We investigate the effective capacity of the SU with MRC diversity under aforementioned constraints in Nakagami fading environments. Particularly, we derive the optimal power allocation to achieve the maximum effective capacity of the SU, and further derive the effective capacity in closed-form. In addition, we further obtain the closed-form expressions for the effective capacities under three widely used power and rate adaptive transmission schemes, namely, optimal simultaneous power and rate adaptation (opra), truncated channel inversion with fixed rate (tifr) and channel inversion with fixed rate without truncation (cifr). Numerical results supported by simulations are presented to consolidate our studies. The impacts on the effective capacity of various system parameters such as the number of antennas, the average interference power constraint and the delay QoS constraint are investigated in detail. It is shown that MRC diversity can significantly improve the effective capacity of the SU especially for cifr transmission scheme.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.97-104
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• 2001

In this paper, we present a new hierarchical model for performance analysis of channel allocation and packet service protocol in wireless n network. The proposed hierarchical model consists of two parts : upper and lower layer models. The upper layer model is the structure state model representing the state of the channel allocation and call service. The lower layer model, which captures the performance of the system within a given structure state, is the wireless packet retransmission protocol model. These models are developed using SRN which is an modeling tool. SRN, an extension of stochastic Petri net, provides compact modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. Fixed point iteration is used to determine the model parameters that are not available directly as input. That is, the call service time of the upper model can be obtained by packet delay in the lower model, and the packet generation rates of the lower model come from call generation rates of the upper model.

• Food Science of Animal Resources
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• v.31 no.4
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• pp.603-608
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• 2011

The objective of this study was to investigate factors related to carcass traits of Hanwoo. In the statistical model developed in this study, slaughterhouse, carcass year, carcass month and sex effects were used as fixed effects and carcass traits (carcass weight, marbling score, loineye muscle area, backfat thickness and meat yield index) as covariations. The grading service data for 285,515 Hanwoo, which were evaluated by Animal Products Grading Service from 2005 to 2007, were used in this study. The partial R-square values of the fixed effects and the marbling score (MS), loineye muscle area, back-fat thickness, meat yield index and carcass weight (CW) on auction prices (AP) of the carcass and carcass price (CP) of the animals were estimated. The most important estimated trait in AP was MS. However, CW is the most important estimated trait on the CP and the MS also has secondly significant effect on the CP. In conclusion, MS as well as CW should maximize the farmer profits and establish a breeding scheme for Hanwoo.