• Journal of Communications and Networks
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• v.12 no.5
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• pp.499-509
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• 2010

A plethora of transmission control protocol (TCP) congestion control algorithms have been devoted to achieving the ultimate goal of high link utilization and fair bandwidth sharing in high bandwidth-delay product (HBDP) networks. We present a new insight into the TCP congestion control problem; in particular an end-to-end delay-based approach for an HBDP network. Our main focus is to design an end-to-end mechanism that can achieve the goal without the assistance of any network feedback. Without a router's aid in notifying the network load factor of a bottleneck link, we utilize goodput and throughput values in order to estimate the load factor. The obtained load factor affects the congestion window adjustment. The new protocol, which is called TCP-goodput and throughput (GT), adopts the carefully designed inversely-proportional increase multiplicative decrease window control policy. Our protocol is stable and efficient regardless of the link capacity, the number of flows, and the round-trip delay. Simulation results show that TCP-GT achieves high utilization, good fairness, small standing queue size, and no packet loss in an HBDP environment.

• Science of Emotion and Sensibility
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• v.5 no.2
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• pp.63-72
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• 2002

In order to examine universal design, 1 have developed two analytical methodologies based on 3P(point) task analysis: structured task analysis and task matrix analysis. I also extracted nine universal design items, namely (1) adjustment, (2) redundancy, (3) specification and function transparency, (4) feedback and (5) error tolerance, (6) effective acquisition of information, (7) ease of understanding and judgment, (8) comfortable operation, and (9) continuity of information and operation. Structured task analysis is used to uncover problems in each of the tasks constituting a job for each functionally challenged condition of users, and solutions to the extracted problems are examined in terms of the above-mentioned nine universal design items. Task matrix analysis calls for the production of a table for each task in a job. In each table, nine items form the columns, and the horizontal rows list all disability types. Then, solutions are formulated for each cell formed by the intersecting columns and rows. Using these two analysis methods, 1 have conducted a verification experiment for the universal design of a public bus. The results of the research have enabled me to propose various ,solutions from a system-based perspective, instead of coming up with the superficial and isolated solutions which are normally produced when conventional analytical methods are used.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.144-151
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• 2002

In order to examine universal desist I have developed two analytical methodologies based on 3P(point) task analysis: structured task analysis and task matrix analysis. I also extracted me universal design items, namely (1) adjustment (2) redundancy, (3) specification and function transparency, (4) feedback and (5) error tolerance, (6) effective acquisition of information, (7) ease of understanding and judgment (8) comfortable operation, and (9) continuity of information and operation. Structured task analysis is used to uncover problems in each of the tasks constituting a job for each functionally challenged condition of users, and solutions to the extracted problems are examined in terms of the above-mentioned nine universal design items. Task matrix analysis calls for the production of a table for each task in a job. In each table, nine items from the columns, and the horizontal rows list all disability types. Then, solutions are formulated for each cell formed by the intersecting columns and rows. Using these two analysis methods, T have conducted a verification experiment for the universal design of a public bus. The results of the research have enabled me to propose various solutions from a system-based perspective, instead of coming up with the superficial and isolated solutions which are normally produced when conventional analytical methods are used.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1768-1789
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• 2016

In contemporary video streaming systems based on HTTP protocol, video players at the client side are responsible for adjusting video quality to network conditions and user expectations. However, when multiple video clips are streamed simultaneously, an intricate application logic implemented in the video players overlays the TCP mechanism which is responsible for a balanced access to a shared network link. As a result, some video players may not obtain a fair share of network throughput and may be vulnerable to an unstable video bit-rate. Therefore, we propose to simplify the algorithms implemented in the video players, which are responsible for the adjustment of video quality and constrain their functionality only to sending feedback to a server about a state of the player buffer. The main logic of the system is shifted to the server, which is now responsible for bit-rate selection and prioritisation of the video streams transmitted to multiple clients. To verify our proposition, we performed several experiments in a laboratory environment which show that when the server cooperates with the clients, the video players experience fewer quality switches and the system achieves better fairness when allocating network throughput among the video players. However, this comes at the cost of worse utilisation of network bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.6
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• pp.599-607
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• 2004

In this paper, using phase locked loop(PLL) synthesizer, we introduce a novel but simple and low cost frequency modulation(FM) circuit of a flat peak frequency deviation fur modulation signal whose frequency covers from outside to inside of the loop-bandwidth of PLL. The FM circuit was basically designed to compensate an amount of feedback of the loop filter in PLL. The circuit also includes the capability of the adjustment of peak frequency deviation and of blocking the intereference with the loop filter. The designed circuit was successfully implemented and showed the flat frequency deviation as expected in the design. In addition, the novel measurement method of the wideband FM modulation index is suggested verified With the suggest measurement, it can be successfully shown the designed circuit has the expected frequency deviation.

• Journal of Digital Convergence
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• v.6 no.1
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• pp.53-61
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• 2008

For the domestic digital contents, a proactive cooperation system or framework between the government, the businesses and research institutions, which would allow for free flow of interaction among these players, can play that role. We have proposed and realized the Dynamic Coordinating Framework(DCF) to bridge these gaps among the major players in the industry. The the Dynamic Coordinating Framework rests on the following major functions. The first major function of the DCF is to decipher any ambiguity that may be embedded in external inputs by stratified role and bias. The second function is to create cooperative groups that will deal with the ambiguities based on its consequent situation. The third is a feedback function that will draw out a new cooperative way by re-feeding the capacities and the conflicts that stem from the existing organizations and strategies into cooperation and adjustment process. Our DCF has compared and evaluated with England and Australia digital content industry models under AHP(Analytic Hierarchy Process) method. DCF has turned out to be well designed and have strong points based on OECD innovation and cooperation criteria.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.2
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• pp.132-139
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• 2009

Yield is a very important measure that can expresses simply for productivity and performance of company. So, yield is used widely in many industries nowadays. With the development of the information technology and online based real-time process monitoring technology, many industries operate the production lines that are developed into automation system. In these production lines, the product structures are very complexity and variety. So, there are many multi-variate processes that need to be monitored with many quality characteristics and associated process variables at the same time. These situations have made it possible to obtain super-large manufacturing process data sets. However, there are many difficulties with finding the cause of process variation or useful information in the high capacity database. In order to solve this problem, neural networks technique is a favorite technique that predicts the yield of process for process control. This paper uses a neural networks technique for improvement and maintenance of yield in manufacturing process. The purpose of this paper is to model the prediction of a sub process that has much effect to improve yields in total manufacturing process and the prediction of adjustment values of this sub process. These informations feedback into the process and the process is adjusted. Also, we show that the proposed model is useful to the manufacturing process through the case study.

• Korea Journal of Hospital Management
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• v.16 no.1
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• pp.77-100
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• 2011

The purpose of this study is to the improvement of general hospital outpatients waiting time using Theory Of Constraints(TOC) methodology and to the development of a Reception Desk in general hospital. This study is to provide decision-making guidelines for hospital managers and to provide feedback for the efficiency of job process. The target people of the study are outpatients and Cashiers on Chungnam national university hospital in Daejeon. The methods of study are summarized as follows. First, The team managers from a Reception Desk group were appointed. This team managers have the adjustment authority to the Outpatients schedule of doctor and Cashier members. Second, The consolidation of the general Reception desk and special inspection the Reception Desk. A movement line and waiting time of patients were simple and fast to accept. As a result of study, it shows that the TOC is the method for a job process and waiting time improvement, patients' satisfaction increase and we need an objective measurement indexes in the medical treatment industry.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.68-73
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• 2002

This paper presents the implementation of wide-band RFIC amplifier operating from near 50 MHz to 3 GHz using Tachyonics SiGe HBT foundry. Voltage shunt feedback is used for the flat gain and the broad band impedance matching. Initial design parameters are calculated through the low frequency small signal analysis. Since the HBT model was not available at the design time, discrete tuning board was made for fine adjustment in the low frequency range. Fabricated amplifier shows 12 dB gain with 1 dB fluctuation and P1 dB reaches 15 dBm at 850 MHz.

• Journal of Information Technology Services
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• v.20 no.5
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• pp.55-71
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• 2021

Technostress management is increasingly getting important as ICT advances and infiltrates every job and task. Especially with the advent of COVID-19, workers had to switch to teleworking utilizing ICT extensively. In this study, we developed a research model explaining antecedents and their impacts on technostress in telecommuting context, especially under the COVID-19 situation. The result revealed that techno-complexity, techno-invasion, and techno-overload are the dominant factors that affect the negative psychological responses in the COVID-19 situation. Among them, we found that techno-overload maintain the most significant influence. It is due to the lack of instant feedback on workload allocations in telework and the lack of adjustment period with the sudden shift to telecommuting. In the case of techno-complexity, employees seem to experience difficulty acquiring new technical skills. Finally, the techno-invasion came out significant, signifying the infiltration of working space by home-related activities. The emotion-focused coping strategy had a moderating effect. In contrast, the problem-focused coping strategy had no significant effect, indicating that an appropriate emotional coping strategy is more important for workers undergoing extreme changes in the work environment. Subsequently, practical and theoretical implications, limitations, and future research directions are discussed.