• Journal of Communications and Networks
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• v.1 no.2
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• pp.134-142
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• 1999

We have developed fully functional Video Server and Client applications which can transmit, receive, decompress and display compressed video over various networks. Our video trans-port allows dynamic rate control feedback, loss detection, and repair requests from Clients to the Server. Our experiments show how feedvack-before-degradation scheme for rate adaptation maintains good display frame-rate for video playback. We show how the playback degradation(reduction in display frame-rate) oc-curs and what happens if corrective measures are not taken to im-prove the situation. The degradation is attributed to the increased internal kernel buffering which consumes scarce CPU resources. We demontrate with our experimental results that ServerNet, with improved hardware delivery guarantees, can significantly reduce host CPU resource consumption while serving video streams. We present the maximum number of streams which can be served for each of ATM and ServerNet interconnects. The appropriate user-level packet size for the video server are also determined for each case.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.226-228
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• 2005

This paper deals with power system stabilization problem using a network control system in which the control is applied through a communication channel in feedback form. Analysis and synthesis issues are investigated by modeling the packet delivery characteristics of the network as a Bernoulli random variable, which is described by a two state Markov chain. This model assumption yields an overall system which is described by a discrete-time Markov jump linear system. These employ the norm to measure the performance of the system, and they compute the norm via a necessary and sufficient matrix inequality condition.

• Korean Management Science Review
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• v.26 no.3
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• pp.37-54
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• 2009

E-learning is a networked phenomenon allowing for instant revisions and distribution, and goes beyond training and instruction to the delivery of information and tools to improve performance. The proponents of e-learning emphasizes that students learn more effectively when they interact and are involved with other students participating in similar endeavors. The paper outlines the process of development and design of e-learning based Management Sciences course, with the aim of ensuring widespread use, in undergraduate business program. Experiences in introducing students to e-learning course are reported. Feedback from students has been very positive but also indicates the need for ongoing support and direction. In addition, a survey was used to identify the determinants of students' academic performance of Management Science, and PLS based model is developed to analyze the results. Statistical results concerning the hypothesized model are provided.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.73-78
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• 1998

Our platform introduced in this paper is based on DAVIC specifications which define high quality multimedia services with some extensions to provide user friendly and uniform interface to its users. We designed and implemented an integrated service platform for high quality interactive multimedia services, swithed digital broadcasting, and Internet services. The integration in terms of a service provider system, a delivery system, and a service user system is taken into account. Our research results in the development of integrated high quality interactive and digital broadcasting multimedia services with web-based common user interface and its experience will be feedback to the field trial service which will be launched from next year.

• Journal of Families and Better Life
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• v.31 no.2
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• pp.93-108
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• 2013

This study aimed to analyze the functionality and healthiness of family rules through a relational analysis of the relationship between the rule frequency by sub-family system and the content properties shown in the 'family constitution', It also aimed to examine the relationship between the perception degree of healthy family elements and the family subsystem rules and prepare the project development plans. As a result, it was a found that there were many dysfunctional rules, and healthiness was not satisfied. Project development plans include specific project plans, delivery systems, an orientation for practitioners, the necessity of evaluation and feedback, family health diagnosis, association with other project areas, and small scale operations.

• Journal of Communications and Networks
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• v.4 no.2
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• pp.118-127
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• 2002

This paper proposes a new scheme - parallel control scheme with feedback control (PCFC) for ABR services in ATM networks. The information from a source is split into a number of streams, for delivery over separate parallel connections with particular coding. At the receiver, the original information is reconstructed by the received packet from the parallel connections. The effects of PCFC on the network performance are due to two factors: Traffic splitting and load balancing. By combinations of analysis and simulation, this paper studies the implications of PCFC for how the ABR parameters should be scaled and the advantages of PCFC compared with other existing schemes.

• Clinical and Experimental Pediatrics
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• v.61 no.8
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• pp.239-244
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• 2018

Purpose: Hypothermia at admission is associated with increased mortality and morbidity in preterm infants. We performed a quality improvement (QI) effort to determine the impact of a decrease in admission hypothermia in preterm infants. Methods: The study enrolled very low birth weight (VLBW) infants born at Gangnam Severance Hospital between January 2013 and December 2016. This multidisciplinary QI effort included the use of occlusive wraps, warm blankets, and caps; the delivery room temperature was maintained above $23.0^{\circ}C$, and a check-list was used for feedback. Results: Among 259 preterm infants, the incidence of hypothermia (defined as body temperature <$36.0^{\circ}C$) decreased significantly from 68% to 41%, and the mean body temperature on neonatal intensive care unit admission increased significantly from $35.5^{\circ}C$ to $36.0^{\circ}C$. In subgroup analysis of VLBW infants, admission hypothermia and neonatal outcomes were compared between the pre-QI (n=55) and post-QI groups (n=75). Body temperature on admission increased significantly from $35.4^{\circ}C$ to $35.9^{\circ}C$ and the number of infants with hypothermia decreased significantly from 71% to 45%. There were no cases of neonatal hyperthermia. The incidence of pulmonary hemorrhage was significantly decreased (P=0.017). Interaction analysis showed that birth weight and gestational age were not correlated with hypothermia following implementation of the protocol. Conclusion: Our study demonstrated a significant reduction in admission hypothermia following the introduction of a standardized protocol in our QI effort. This resulted in an effective reduction in the incidence of massive pulmonary hemorrhage.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.434-442
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• 2012

Several gateway selection schemes have been proposed that select gateway nodes based on a single Quality of Service (QoS) path parameter, for instance path availability period, link capacity or end-to-end delay, etc. or on multiple non-QoS parameters, for instance the combination of gateway node speed, residual energy, and number of hops, for Mobile Ad hoc NETworks (MANETs). Each scheme just focuses on the ment of improve only a single network performance, i.e., network throughput, packet delivery ratio, end-to-end delay, or packet drop ratio. However, none of these schemes improves the overall network performance because they focus on a single QoS path parameter or on set of non-QoS parameters. To improve the overall network performance, it is necessary to select a gateway with stable path, a path with themaximum residual load capacity and the minimum latency. In this paper, we propose a gateway selection scheme that considers multiple QoS path parameters such as path availability period, available capacity and latency, to select a potential gateway node. We improve the path availability computation accuracy, we introduce a feedback system to updated path dynamics to the traffic source node and we propose an efficient method to propagate QoS parameters in our scheme. Computer simulations show that our gateway selection scheme improves throughput and packet delivery ratio with less per node energy consumption. It also improves the end-to-end delay compared to single QoS path parameter gateway selection schemes. In addition, we simulate the proposed scheme by considering weighting factors to gateway selection parameters and results show that the weighting factors improve the throughput and end-to-end delay compared to the conventional schemes.

• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.165-174
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• 2023

This study analyzed the purchase status of athleisure wear and consumers' dissatisfaction with online shopping post-COVID-19. The target population comprised female consumers in their 20s to 50s who are interested in exercise and fashion. The study investigated differences according to age. It was found that athleisure wear was purchased once every two to three months and used as sportswear and/or daily wear. Purchase information was obtained via the Internet, and purchases were made online. Design, price, wear sensation, and textiles were the most important selection criteria, and T-shirts and leggings were the most frequently purchased garments. Additionally, textile characteristics such as moisture-absorbing and quick-drying as well as elasticity were evaluated as important. Online shopping of athleisure wear has increased since COVID-19 due to the time savings, low price, opportunity to compare several products, and delivery convenience. However, consumers were dissatisfied due to the differences between the screen image and the actual product, the inconvenience of returns, exchanges, and refunds, the lack of product information, product quality, and delivery. Furthermore, it was found that pursuing value of athleisure wear differed according to age. Consumers in their 20s and 30s required athleisure wear with the characteristics of sportswear and daily or urban wear and those in their 40s and 50s required garments with good performance as sportswear. Based on consumer feedback, it is necessary for manufacturers to provide product information that can improve product reliability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.50-58
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• 2008

The use of space-division multiple access(SDMA) in the downlink of multiuser multi-input/multi-output(MIMO) wireless transmission systems can provide substantial gains in system throughput. When the channel state information(CSI) is available at the transmitter, a considerable performance improvement can be attained by adapting the transmission rates to the reported CSI. In addition, to combat frequency selective fadings in wideband wireless channels, bit-interleaved coded OFDM(BIC-OFDM) modulation schemes are employed to provide reliable packet delivery by utilizing frequency diversity through channel coding. In this paper, we propose an adaptive modulation and coding(AMC) scheme combined with an opportunistic scheduling technique for the MIMO BIC-OFDM with bandwidth-limited feedback channels. The proposed scheme enhances the link performance by exploiting both the frequency diversity and the multiuser diversity. To reduce the feedback information, the proposed AMC scheme employs rate adaptation methods based on an OFDM symbol rather than on the whole subchannels. Simulation results show that the proposed scheme exhibits a substantial performance gain with a reasonable complexity over single antenna systems.