• Title/Summary/Keyword: External connection method

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A Study on the Calculation of Optimal Compensation Capacity of Reactive Power for Grid Connection of Offshore Wind Farms (해상풍력단지 전력계통 연계를 위한 무효전력 최적 보상용량 계산에 관한 연구)

  • Seong-Min Han;Joo-Hyuk Park;Chang-Hyun Hwang;Chae-Joo Moon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.1
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    • pp.65-76
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    • 2024
  • With the recent activation of the offshore wind power industry, there has been a development of power plants with a scale exceeding 400MW, comparable to traditional thermal power plants. Renewable energy, characterized by intermittency depending on the energy source, is a prominent feature of modern renewable power generation facilities, which are structured based on controllable inverter technology. As the integration of renewable energy sources into the grid expands, the grid codes for power system connection are progressively becoming more defined, leading to active discussions and evaluations in this area. In this paper, we propose a method for selecting optimal reactive power compensation capacity when multiple offshore wind farms are integrated and connected through a shared interconnection facility to comply with grid codes. Based on the requirements of the grid code, we analyze the reactive power compensation and excessive stability of the 400MW wind power generation site under development in the southwest sea of Jeonbuk. This analysis involves constructing a generation site database using PSS/E (Power System Simulation for Engineering), incorporating turbine layouts and cable data. The study calculates reactive power due to charging current in internal and external network cables and determines the reactive power compensation capacity at the interconnection point. Additionally, static and dynamic stability assessments are conducted by integrating with the power system database.

Neuronal activity in the periaqueductal gray associated with chronic cannula implantation and microdialysis (Chronic cannula implantation 및 microdialysis가 periaqueductal gray내 신경세포 활성에 미치는 영향)

  • Lee, Jang-hern;Han, Ho-jae;Yang, Il-suk
    • Korean Journal of Veterinary Research
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    • v.38 no.4
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    • pp.720-729
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    • 1998
  • Immunohistochemical technique of the c-fos primary gene protein, Fos, was used to analyze the effects of external factors on the neuronal activities in the periaqueductal gray(PAG) of the intact rats, sham-operated rats and post-operated stress control rats. In addition, the number of Fos positive neurons has been evaluated to verify the effects of cannula implantation and veratridine treatment on the neuronal activities in PAG area. The results were summerized as follow : 1. There was no significant difference in the number of Fos positive neurons observed in the caudal and middle portion of lateroventral PAG from cannula implanted rats and sham operated rats. 2. The number of Fos positive neurons in the PAG was not changed by the stress induced by connection of collecting tube to rats for 12 hours as compared to that of intact rats. 3. In the saline treated group, the Fos immunoreactivity in the PAG did not changed at 30 minutes and 1 hour after saline treatment as compared to that of intact rats. However, the number of Fos positive neurons was significantly increased at 2 hours after treatment compared to that of saline treated rats at 30 minutes after treatment. 4. The Fos immunoreactivity was dramatically increased at 30 minutes, 1 hour and 2 hours after veratridine treatment as compared to those of saline treated groups. The number of Fos immunoreative neurons showed the maximal level at 2 hours after veratridine treatment. 5. The Fos positive neurons induced by saline and veratridine treatment were mainly distributed in front of the microdialysis window. These results suggest that new microdialysis demonstrated in this study improves efficiency and accuracy to confine the neuronal activity in front of microdialysis window site. Moreover, this directional specificity allows us to locate probe tips adjacent to the brain area of the interest site rather than centering the probes within that brain area. Finally, This microdialysis method can be used to dialyse the neurotransmitters using concious and freely moving rats.

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The Development of Industrial Communication Monitoring Board using AVR (AVR을 이용한 산업용 통신 모니터링 보드 개발)

  • Eum, Sang-hee;Lee, Byong-Hoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.6
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    • pp.1177-1182
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    • 2016
  • The most industrial instruments for monitoring and control are occurring the extension problem and the external protocol compatibility. In this paper, we developed the boards for the industrial communication monitoring that are able to convert the protocol in various communication between devices and instruments. These are consisted the main board and several sub-board. They can have extension using the main board connection. The sub-board support the each communication method or data transfer. The main board was used the Atmega 2560 Microprocessor of AVR series, and the sub-boards are have the Atmega 256 or Atmega 128 in the AVR series. We have designed to connect the sub-board using placed the 4 RS485 serial slots in the main board. The sub-boards were developed to support the analog and digital I/O. These are able to have monitoring by CAN and Ethernet communication. The experimental results, we obtained good data transfer rate and conversion rate.

A Study on Left-Renying and Right-Qikou Pulse Diagnosis(左人迎·右氣口 脈診法) ('좌인영(左人迎)·우기구(右氣口)' 맥진법(脈診法)에 관(關)한 고찰(考察))

  • Kwak, Bumhee;Yoon, Jonghwa
    • Journal of Korean Medical classics
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    • v.33 no.1
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    • pp.89-101
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    • 2020
  • Objectives : The purpose of this study is to research the Left-Renying and Right-Qikou pulse diagnosis. Methods : We set up locations of the Renying pulse(人迎脈) and the Qikou pulse(氣口脈) on left hand and right hand. On the basis of the medical texts and papers, we researched the relations between the Left-Renying and Right-Qikou pulse diagnosis and the etiological factors(病因), background of appearance of the Left-Renying and Right-Qikou pulse diagnosis, and practical use of medical practitioners of many generations to the Left-Renying and Right-Qikou pulse diagnosis. Results & Conclusions : The Left-Renying and Right-Qikou pulse diagnosis is a method to diagnosis the etiological factors, while it could also be assumed as a tool to apply herbal medicine. This assumption could be made based on the seventh volume of 『Maijing(脈經)』 of Wang Shuhe(王叔和). Chen Wuze(陳無擇) emphasized its function to distinguish etiological factors in 『Sanyinjiyibingzhengfanglun(三因極一病證方論)』, as did Li Dongyuan(李東垣) in 『Neiwaishangbianhuolun(內外傷辨惑論)』. Meanwhile, the connection between Left-Renying and Right-Qikou pulse diagnosis and Zangfu(臟腑) seems to have first been made in 『Maiyu(脈語)』 of Wu Kun(吳昆), while 『Zhenjiazhengyan(診家正眼)』 of Li Zhongzi(李中梓) shows traces of progress since the 『Maiyu』.

Plasticity of Transparent Design Expressed in Contemporary Fashion (현대 복식에 표현된 투명디자인의 조형성)

  • 정연자
    • Journal of the Korea Fashion and Costume Design Association
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    • v.3 no.2
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    • pp.51-62
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    • 2001
  • This study was intended to investigate the contemporary meaning of transparent design expressed in contemporary fashion by inquiring into its plasticity expressed in contemporary design and fashion and analyzing the association between them. It used the comparative anesthetic method widely used by H. W lfflin and other scholars in eliciting the differences and similarities in styles. It attempted to investigate the plasticity of transparent design expressed in contemporary design by dividing it into the epidermal, spatial and ideological effects. Contemporary design expressed the epidermal effects such as lightness(nimbleness), smoothness, contrast and stress It expressed the spatial effects such as spatial flexibility through the interpenetration of interior and exterior spaces, expansion of the space and the like. And it expressed ideological effects such as openness, pureness, playfulness and the like. In terms of lightness, contemporary design expressed actual or visual lightness by using transparent materials. In terms of the interpenetration of interior and exterior spaces, it expressed the interpenetration of the interior space into the exterior spaces and vice versa. In terms of spatial expansion, contemporary design expressed the infinite spatial connection by drawing the exterior space into the interior space. Contrast and stress were formed by imposing visual unity on contemporary fashion by using opaque and transparent materials. In terms of openness, contemporary design expressed contemporary people's candor and dependability by making the inside of the building or object look outward. To express pureness, contemporary design used the clear and transparent image by using the glass or translucent materials taking on the pure property. To express playfulness, contemporary made use of the vagueness of the spatial boundary, the locational switching of inner and outer spaces, and interesting external forms occurring when light pass through opaque and transparent materials.

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ViP: A Practical Approach to Platform-based System Modeling Methodology

  • Um, Jun-Hyung;Hong, Sung-Pack;Kim, Young-Taek;Chung, Eui-Young;Choi, Kyu-Myung;Kong, Jeong-Taek;Eo, Soo-Kwan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.5 no.2
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    • pp.89-101
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    • 2005
  • Research on highly abstracted system modeling and simulation has received a great deal of attention as of the concept of platform based design is becoming ubiquitous. From a practical design point of view, such modeling and simulation must consider the following: (i) fast simulation speed and cycle accuracy, (ii) early availability for early stage software development, (iii) inter-operability with external tools for software development, and (iv) reusability of the models. Unfortunately, however, all of the previous works only partially addresses the requirements, due to the inherent conflicts among the requirements. The objective of this study is to develop a new system design methodology to effectively address the requirements mentioned above. We propose a new transaction-level system modeling methodology, called ViP (Virtual Platform). We propose a two-step approach in the ViP method. In phase 1, we create a ViP for early stage software development (before RTL freeze). The ViP created in this step provides high speed simulation, lower cycle accuracy with only minor modeling effort.(satisfying (ii)). In phase 2, we refine the ViP to increase the cycle accuracy for system performance analysis and software optimization (satisfying (i)). We also propose a systematic ViP modeling flow and unified interface scheme based on utilities developed for maximizing reusability and productivity (satisfying (ii) and (iv)) and finally, we demonstrate VChannel, a generic scheme to provide a connection between the ViP and the host-resident application software (satisfying (iii)). ViP had been applied to several System-on-a-chip (SoC) designs including mobile applications, enabling engineers to improve performance while reducing the software development time by 30% compared to traditional methods.

Correlation Analysis of Tinnitus Severity and Psychiatric Characteristics in Patients with Tinnitus (이명환자에서 이명심각도와 정신의학적 특징의 상관성 분석)

  • Moon, Kyung Ray;Lee, Junghyun H.;Chun, Young-Myoug;Lee, Dayoung
    • Anxiety and mood
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    • v.11 no.2
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    • pp.136-142
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    • 2015
  • Objective : Subjective tinnitus is defined as an acoustic sensation perceived without any external source. Patients with tinnitus have often experienced psychological distress and low quality of life. However, the connection between psychiatric characteristics and tinnitus has not yet been established. The purpose of this study was to investigate the relationship of psychiatric characteristics with tinnitus severity. Method : A total of 124 patients with tinnitus were included in the study. Demographic and clinical characteristics were retrospectively collected in the otolaryngology clinic. The self-reported scales including the Tinnitus Handicap Inventory, the Hospital Anxiety and Depression Scale and the Anxiety Sensitivity Index were used in this study. Results : The Pearson product moment correlation revealed significant correlations between tinnitus severity and psychiatric characteristics including depression (r=0.26, p<0.01), anxiety (r=0.38, p<0.01), anxiety sensitivity (r=0.27, p<0.01). After controlling for age, sex and awareness of tinnitus, tinnitus severity was positively correlated with anxiety (partial r=0.39, p<0.01) and anxiety sensitivity (partial r=0.28, p<0.01). These correlations remained significant in male but not in female patients. Conclusion : Results of the present study indicated that not only anxiety symptoms but also anxiety sensitivity could relate to tinnitus severity. Our findings have implications for the understanding of the psychiatric characteristics in patients with tinnitus.

A Study of application on the Figurative Aesthetics of Oriental Painting (동양회화(東洋繪畵)에서 형상(形象)의 심미작용(審美作用))

  • Jeong Jin-Ryong
    • Journal of Science of Art and Design
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    • v.8
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    • pp.211-239
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    • 2005
  • The purpose of this thesis is to explore a common characteristic of the diverse oriental images mainly from the figurative point of view, and apply it to the contemporary expressions and methods of painting. To do that, I separated the concept of figure into two factors - form and image - and then approached and solved the problems of figure by explaining the two factors respectively. Separating form from image is neither to set two factors against each other nor to isolate any of those values. It is worth dividing the form and the image not only because the image of the oriental painting has a figurative value constituted from an external frame of the form, but also because it has a close connection with the meaning that the form holds inside. These are the reasons why I conceptualize the individual language of form and image. Furthermore, I attempted to investigate how those two factors and mutual relations between them make real figurative images under the principle of harmony and coexistence. The theme of this thesis - the figurative aesthetics and its contemporaneity in the oriental paintings is analyzed based on the understanding of 'figure' within the framework of oriental paintings. A research of image from the figurative point of view is valuable in that it criticizes the past method of thinking, and proposes an alternative formula for new way of thinking. In this regard, I indicated the limit of the theory of form-and-spirit that has been one of the most important conceptual theories . Instead, I' accessed to various aesthetic concepts - that are created in the course of image formulation - from the actual figurative point of view, and then even interpreted it as a figurative value of the oriental paintings and it's application within the specific and practical scope. During the course of research, I explored the conceptual elements of the tradition and the principle of figuration. I expect this study to make a footstone for bringing traditional aesthetics to the contemporary context of oriental painting.

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Voltage Control of Power System Connected to a Wind Farm by Using STATCOM and Reactive Power Compensators (STATCOM과 조상설비를 이용한 풍력단지가 연계된 전력계통의 전압제어)

  • Seo, Gyu-Seok;Park, Ji-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.4
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    • pp.2737-2743
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    • 2015
  • The wind power plant must be able to produce reactive power at the POI bus of a wind farm connected to power system to keep or control the voltage of POI bus. But, the reactive power capability of wind turbines may not be sufficient to control the voltage of POI bus due to the reactive power losses in connection lines between wind farm and POI bus. The solution of this problem is to install an external STATCOM. The proposed cooperative control method of STATCOM and conventional reactive power compensators such as Switched-shunt and tap changing transformer can control the voltage of POI bus more efficiently. The simulation results are shown that the voltage drop of POI Bus of Test System with the arbitrary load change rate to initial loads is improved more than 60% and the voltage of load bus is maintained more than 95% of rated voltage.

A Study on the Service Method of Modern Literature Based on Linked Data (링크드 데이터 기반 근대문학자료의 서비스 방안 연구)

  • Park, Jin-Ho;Kwak, Seung-Jin
    • Journal of the Korean Society for Library and Information Science
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    • v.55 no.2
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    • pp.5-24
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    • 2021
  • This study suggested a plan to convert the modern literary data service of the National Library of Korea into linked data-based services. This is not to simply convert the modern literary data service into linked data, which is the current technological trend. This is to create high-quality source data capable of automated machine processing with continuous connection with various external data and information sources in the long term. To this end, in order to revitalize the service of modern literature and to solve the efficient data linkage with related institutions, various overseas library and bibliographic service cases that adopted linked data were first reviewed to draw implications. In addition, based on the reviewed implications, the plan to reorganize the modern literary service in terms of data management, system management, and user service was described in detail.