• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1212-1218
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• 1999

This paper proposes a new multipath interconnection network(MIN) structure for improving performance which uses widely in the design of multiprocessing, ATM system and VOD server. For improving performance such as passthrough ratio and packet latency, it proposes new routing method which routes one of the collided packets into the i+1-th switching stage of the adding Banyan MIN network when it occurred collision at the i-th switching stage of the basic MIN again when they collide each other. The new improved performance MIN network has been compared with MBSF, TBSF and PBSF structured MIN network from the viewpoint of passthrough ratio and the number of switching stage vs. passthrough ratio. It is shown to improve a performance and to be a simple structure which reducing the number of switching stage of adding MIN in comparison with other structured MIN including TBSF.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.3
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• pp.95-105
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• 2019

A method that applies space-time adaptive signal processing (STAP) algorithm based on an array antenna consisting of multiple antenna elements has been known to be effective to remove wide-band jamming signals in GPS receivers. However, the occurrence of phase distortion in navigation signals has been a problem when navigation signals, from which jamming signals are removed using STAP, are supplied to global positioning system (GPS) receivers. This paper verified the navigation performance degradation as a result of phase distortion. To mitigate this phenomenon, this paper proposes a mode switching scheme, in which a bypass mode is adopted to make the best use of the tracking performance of receivers without performing signal processing when jamming signals are not present or weak, and a STAP mode is employed when jamming signals exceed the threshold value. In this paper, the mode switching scheme is proposed for two environments: when receivers are stationary, and when receivers are moving. This paper confirmed that the performance of position error improved because phase distortion could be excluded due to STAP if the bypass mode was adopted under a condition where the jamming signal power level was below the threshold value in an environment where receivers were stationary. However, this paper also observed that the navigation failed due to the instability of tracking performance of receivers due to phase distortion that occurred at the switching time, although the number of switching could be reduced dramatically by proposing a dual threshold scheme of on- and off-thresholds that switched a mode due to the array antenna characteristics of varying gains according to the jamming signal incident direction in an environment where receivers were moving. The analysis results verified that running the STAP algorithm at all times is more efficient than the mode switching, in terms of maintaining stable navigation and ensuring position error performance, to remove jamming signals in an environment where receivers were moving.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.669-683
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• 1999

Heat dissipation in the domestic switching room has been gradually increased. Therefore, numerical study on the cooling characteristics of the telecommunication system in a switching room for three kinds of the air supply and return flow system was investigated to develop effective flow system. As a result, the cooling performance of the under floor air supply and overhead return flow system was the best.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.3
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• pp.44-51
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• 1999

This paper presents the queuing model for evaluating the performance of TMN EMS with ATM switching systems. TMS for managing ATM switching systems has a hierarchical structure that consists of managers at the top level, agents at the middle, and ATM switching systems at bottom. A manager communicates with several agents, and an agent manages an ATM switching system We define a queuing model in order to predict the capacity and performance for managers in EMS. By evaluating the queuing model, we can predict the average service time and capacity of EMS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.73-79
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• 2001

IP Switching is a new routing technology Proposed to improve the Performance of IP routers. Flow classification is one of the key issues in IP Switching. To achieve better performance, flow classification should be matched to the varying IP traffic and an IP switch should make use of its hardware switching resources as fully as possible. This paper proposes an dynamic flow classification method for IP Switching. By dynamically adjusting the values of its control parameters in response to the present usage of the hardware switching resources, this dynamic method can efficiently match the varying IP traffic and thus improve the performance of an IP switch.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.6
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• pp.131-150
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• 2014

This study investigates factors, which affect subjective judgment of Smartphone users when they switch to a new product or other mobile carrier, and examine a relationship between switching intention and switching expected performance through users of in Korea and China. The results of the study showed that switching intention is positively associated with switching expected performance in both Korean and Chinese users. Brand reliability, functional quality, and general climate for Smartphone business have a significant impact on switching intention in both countries. In addition, personal innovation has a significant impact on switching intention of Korean users but Chinese. However, content quality has the effect on switching intention of Chinese user but Korean. This study provides useful strategies for switching behavior of Smartphone users of two different countries in the mobile industry.

• The Korean Journal of Health Service Management
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• v.1 no.1
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• pp.75-89
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• 2007

The start point of a franchise system such as Lotteria was in 1979. Since 1990, the franchise systems in Korea have rapidly spread over all industry types. As 'Franchise Law' was enforced in 2002, the expansion of a franchise picked up its' speed. The barbers and beauty parlors business has the same expansion trend. However, there was no study about the franchise systems in the barbers and beauty parlors business. The purpose of this study was to find the goodness of fit of the structured equation model proposed and identify the significances of relationships in the variables of justice perceptions, trust, satisfactions, business performances, switching barriers, switching cost etc. This study tries to find a solution for a good development between franchisor and franchisee in the barbers and beauty parlors business in Korea. The theoretical considerations about justice of this study is limited in reciprocal relation justice and procedure justice. And it did make simplify for trust, satisfaction, business performance, switching barrier. And switching barrier did measure as dimension of switching coot. From October 26, 2005 to October 29, this study collected 250 survey questionnaires from the franchisees located in Seoul, Busan, Daegu, Ulsan, and Keoyng-Nam. In analyses of using SPSS Windows 11.0 and LISREL 8.14, this study used 208 cases because 48 cases did not response appropriately. Tn conclusions. reciprocal justice perception and procedure justice jointly determined trust. Secondly, reciprocal justice perception significantly determined satisfaction. Procedure justice perception negatively determined satisfaction, but this relationship was not significant. Thirdly, reciprocal justice perception positively influenced business performance, and procedure justice negatively influenced business performance, but the last relationship was not significant Fourthly, trust positively significantly influenced satisfaction and business performance. Fifthly, satisfaction positively influenced business performance and true determined switching barrier positively. This study shows following: firstly, a composition concept did make structural relationship and secondly, a reciprocal relation justice of a franchisor did appear as an important variable and it gives positive influence to trust, satisfactions, business performance, switching barriers of the franchisees.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.16-23
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• 2003

In this paper, we propose a new optical hybrid switching system that takes advantage of both Optical Burst Switching (OBS) and Optical Circuit Switching (OCS) technologies. This system classifies incoming IP traffic flows into short-lived and long-lived flows for hybrid switching. For performance analysis, we model the system as a single server queue in a Markovian environment. The burst generation process is assumed to follow a two-state Markov Modulated Poisson Process (MMPP), and the service rate fluctuates based on the number of concurrent OCS sessions. Results of the mean delay and queue size for OBS bursts are derived.

• Journal of Power Electronics
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• v.17 no.3
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• pp.601-609
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• 2017

Gallium nitride (GaN) power switching devices are promising candidates for high switching frequency and high efficiency power conversion due to their fast switching, low on-state resistance, and high-temperature operation capability. In order to facilitate the use of these new devices better, it is required to investigate the device characteristics and performance in detail preferably by comparing with various conventional silicon (Si) devices. This paper presents a comprehensive study of GaN high electron mobility transistor (HEMT) based non-isolated point-of-load (POL) synchronous buck converter operating at 2.7 MHz with a high step-down ratio (24 V to 3.3 V). The characteristics and performance of GaN HEMT and three different Si devices are analytically investigated and the optimal operating point for GaN HEMT is discussed. Zero-voltage switching (ZVS) is implemented to minimize switching loss in high switching frequency operation. The prototype circuit and experimental data support the validity of analytical and simulation results.

• The Journal of Information Systems
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• v.30 no.3
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• pp.65-91
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• 2021

Purpose In this study, we investigated the impact of perceived risk and switching costs on switching intention to cloud service based on PPM (Pull-Push-Mooring) model. Design/methodology/approach We focused on revealing the switching factors of the switching intention to the cloud services. The switching factors to the cloud services were defined as perceived risk consisting of performance risk, economic risk, and security risk, and switching costs consisting of financial and learning costs. On the PPM model, we defined the pull factors consisting of perceived usefulness and perceived ease of use, and the push factor as satisfaction of the legacy system, and the mooring factor as policy supports. Findings The results of this study as follows; (1) Among the perceived risk factors, performance risk has a negative effect on the ease of use of pull factors, and finally it was found to affect the switching intention to the cloud services. Therefore, cloud service providers need to improve trust in cloud services, service timeliness, and linkage to the legacy systems. And it was found that economic risk and security risk among the perceived risk factors did not affect the switching intention to the cloud services. (2) Of the perceived risk factors, financial cost and learning cost did not affect the satisfaction of the legacy system, which is a push factor. It indicates that the respondents are positively considering switching to cloud service in the future, despite the fact that the respondents are satisfied with the use of the legacy system and are aware of the switching cost to cloud service. (3) Policy support was found to improve the switching intention to cloud services by alleviating the financial and learning costs required for cloud service switching.