• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.685-688
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• 2001

This paper proposes an SSSC based on multi-bridge inverters. The dynamic characteristic of the proposed SSSC was analyzed by EMTP simulation and a scaled handware model, assuming that the SSSC is inserted in the transmission line of the one-machine-infinite-bus power system. The proposed SSSC has 6 multi-bridge inverters per phase, which generates 13 pulses for each half period of power frequency. The proposed SSSC generates a quasi-simusoidal output voltage by 90 degree phase shift to the line current The proposed SSSC does not require the coupling transformer for voltage injection, and has a flexibility in operation voltage by increasing the number of series connection.

• Wind and Structures
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• v.5 no.5
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• pp.463-478
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• 2002

Lighting and traffic signal columns are mainly stressed by excitation due to natural, gusty wind. Such columns typically have a door opening about 60 cm above ground level for the connection of the buried cable with the column's electric system. When the columns around this notch are inadequately designed, vibrations due to gusty winds will produce considerable stress amplitudes in this area, which lead to fatigue cracks. To give a realistic basis for a reliable and economic design of lighting and traffic signal columns, a number of experimental and theoretical investigations have been made. The proposed design concept allows the life of such columns to be assessed with a satisfactory degree of accuracy.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.1-10
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• 2021

In recent decades, the heterogeneous and dynamic behavior of Internet traffic has placed new demands on the adaptive resource allocation of the optical network infrastructure. However, the advent of multifiber elastic optical networks has led to a higher degree of spectrum fragmentation than conventional flexible grid networks due to the dynamic and random establishment and removal of optical connections. In this paper, we propose heuristic routing and dynamic slot allocation algorithms to minimize spectrum fragmentation and reduce the probability of blocking future connection requests by considering the power consumption in elastic multifiber elastic optical networks.

• The Pure and Applied Mathematics
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• v.28 no.2
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• pp.155-185
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• 2021

Orders and types of entire functions have been actively investigated by many authors. In this paper, we investigate some basic properties in connection with sum and product of generalized relative order (𝛼, 𝛽), generalized relative type (𝛼, 𝛽) and generalized relative weak type (𝛼, 𝛽) of entire functions with respect to another entire function where 𝛼, 𝛽 are continuous non-negative functions on (-∞, +∞).

• Journal of Korea Multimedia Society
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• v.25 no.6
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• pp.844-851
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• 2022

This study intends to propose an evaluation tool for analyzing the sense of immersion of realistic VR game contents in the metabus game industry, which is rapidly increasing recently. This paper presents an analysis tool to measure the degree of immersion after selecting three types VR games for research, and analyzing the immersion way method of the game. The research method analyzes how the user and the sense of immersion formed in the storytelling in the game can have an effect. Based on the results, we present an sense of immersion analysis and measurement method for evaluating the usability of VR game contents, which is a key element in the metaverse era. Furthermore, it expands the immersion element that appears in storytelling to the game industry and seeks a new direction of development through connection with the VR game industry.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2669-2681
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• 2021

Valve is widely used in the various industry areas to adjust and control the flow. Cavitation frequently takes place and sometimes is inevitable in various types of valve to cause the erosion damage. Therefore, how to control and minimize the effect of cavitation is still an important topic. This study numerically investigates the cavitating flow in a control valve with a perforated cage. The effects of some parameters on the cavitation are discussed. It also discusses to use the throttling steps to govern the cavitating flow. The results show that the opening degree of valve and the length of downstream divergent connection both influence the cavitation. The increase of the divergent length reinforces the cavitation. And the larger the opening of valve is, the intenser the cavitation is and the more vapor is present. The more throttling steps are helpful to decrease the cavitation.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.1-7
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• 2023

TCP is considered a major candidate transport protocol even for constrained IoT networks due to its ability to integrate into the existing network infrastructures. Since TCP implementations such as uIP TCP often allow only a single TCP segment per connection to be unacknowledged at any given time due to resource constraints, the congestion control relies only on RTO management. In our previous work, to address the problem that uIP TCP performs poorly particularly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe, we proposed a RTO scheme for uIP TCP and validated the performance through Cooja simulation. In this study, we investigate the effect of other factors that were not considered in our previous work. More specifically, the effect of traffic intensity, the degree of the hidden terminal problem, and RDC is investigated by varying the offered load and the transmission range, and the RDC channel check rate. Simulation results imply that we need to further investigate how to improve TCP performance when the radio duty cycling mechanism is used.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1171-1176
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• 2005

Dispute related to construction projects involving numerous persons is one of the biggest challenges faced by contractors today. It costs a substantial amount of money and time in resolving these kinds of claims. Recently, with the changes in the construction environment and thought of relation with owner, the number of construction claims has increased. But, a majority of these claims do not prevail, and in fact, frequently get dismissed in its entirety. The reasons for such dismissals include the ignorance about the claims, lack of clear and convincing evidence, and so on. But most of reasons are the claims are not managed well on construction process. This paper analyzes the failure causes by relying on past claim failure cases, and then drew works that have connection with failure causes through interview. It also presented importance degree of construction management works.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.346-347
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• 2020

This paper presents the two combination methods for leakage current reduction in photovoltaic system PCS. The leakage current in the photovoltaic system generated from the parasitic capacitance existing between the photovoltaic system and ground relevance to common mode voltage caused by PWM switching. Firstly, Leakage current reduced by a PWM method using two carriers with 180-degree phase different. Secondly, the leakage current is more reduced by connecting LCL filter to the mid-point of DC link. This combining method is revealed in PSIM simulation with 1 uF parasitic capacitance.

• Journal of Korean Home Economics Education Association
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• v.19 no.1 s.43
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• pp.1-14
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• 2007

This study aimed to analyze the contents of clothing and textile areas in practical arts, technology and home economics, and science of home economics courses, and the degrees of vertical connections among them. Totally 21 textbooks were chosen for this study, which consist of fifth and sixth grade practical arts textbooks(one from each grade), sixteen technology and home economics textbooks(eight from each eighth and tenth grade), and three high school science of home economics textbooks. In order to analyze systematically the degrees of vertical connections, clothing and textile areas were divided into 6 large sections, which were subdivided into 48 specific categories(contents) by content analysis. The method of connection analysis was based on development(constant continuity and sequence), repetition (continuity without considering sequence), gap(sequence without considering the continuity of curriculum), and reduction(the lack of both continuity and sequence). The connection analysis were done in 48 categories separatively. In the sections of clothing attire and clothing management, the most categories(46.1% and 44.5%) were evaluated as having connections of reductions. No category was analyzed as development in the section of clothing planning and the most categories(83.3%) had connections of repetitions. In the clothing material section showed to be the section with the most in-depth and expanded content compared to the previous educational levels, with developed categories of 50%. The most degree of connection in the clothing and textile areas of practical arts, technology and home economics, and science of home economics subjects was the development at 29.2%, followed by repetition at 25%, reduction at 25%, and finally gap at 20.8%. Developed categories were relatively more than repetitive, reduced, or gap contents. However, as the connection between grades was not highly outstanding, it was difficult to say that the connection of the curriculum was adequately distributed according to the school grades.