• Journal of Integrative Natural Science
• /
• v.16 no.4
• /
• pp.139-145
• /
• 2023

Due to changes in the distribution system and increased demand for renewable energy, interest in technology to increase the limit capacity of distributed energy grid connection using grid flexible resources is also increasing. Recently, the distribution system system is changing due to the increase in distributed power from renewable energy, and as a result, problems with the limited capacity of the distribution system, such as waiting for renewable energy to connect and increased overload, are occurring. According to the power generation facility status report provided by the Korea Power Exchange, of the total power generation capacity of 134,020 MW as of 2021, power generation capacity through new and renewable energy facilities is 24,855 MW, accounting for approximately 19%, and among them, power generation through solar power accounts for a total portion of the total. It was analyzed that the proportion of solar power generation facilities was high, accounting for 75%. In the future, the proportion of new and renewable energy power generation facilities is expected to increase, and accordingly, an efficient operation plan for the distribution system is needed. Advanced country-type NWAs that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power in order to improve distribution network use efficiency without expanding distribution facilities due to the expansion of renewable energy. An integrated operating system is needed. In this study, in order to improve the efficiency of distribution network use without expanding distribution facilities due to the expansion of renewable energy, we developed a method that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power. We want to develop an integrated operation system for NWAs similar to that of advanced countries.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.1
• /
• pp.56-62
• /
• 2010

This paper describes the analysis of loop impedance characteristics by impedance alteration of protective conductors and operating characteristics of electric leakage circuit breaker by each earth systems(TT system, TN-S system and TN-C system) in IEC 60364. As a result, loop Impedance was affected by resistance & inductance. The current& voltage characteristics about earth system were identified that the TN-S system was high fault current & low touch voltage. TN-C system was almost same the TN-S system but TT system was low fault current & high touch voltage.

• Journal of the Korean Society of Costume
• /
• v.57 no.1 s.110
• /
• pp.130-146
• /
• 2007

Thought of postmodernism accepted between variety and differentiation is characterized by variability and indeterminacy aimed at continuous change. For that reason, modern fashion has been grouping a lot of manners for creation of the various different form and structure. This paper studies the characteristics of the folding system, which expands efficiency of the spatial utility and shows various forms. Folding system expressed in modern fashion could be divided the pleats, which were made of the folding, and the dreaperies, which were made of bending. This selects the pleats as a enlarged concept of the folding system that contains between the former and the letter. Pleats did not mean two dimensional folding surfaces, but three dimensional spatial structures. For understanding of the folding system as a three dimensional spatial structure, this is utilized with the thought of the 'le pli' of G.W.Leifniz and G.Deleuze. The pleats expressed in modern fashion can subdivided into 4 sets; crinkle system, origami system, fractal pleats by folding system, and drapery system. And Formative characteristics of the pleats are analyzed with enlargement, fluidity, deconstruction, irregularity.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.40 no.3
• /
• pp.42-53
• /
• 1998

About 50 percent of irrigation and drainage facilities in our country are deteriorated as they were constructed over 40 years ago. Worsening the problems in function might be caused by these facilities' constant exposure to the elements. With these reason, efficient maintenance and management of irrigation and drainage facili- ties are required. A computerized system is tailored on the basis of the each characteristics'data of irrigation and drainage facilities. The unified management system to be introduced in this study is a package program consisting of three subprograms. Facility Management(FM) system, the first component, is a relational database system for image processing and registering the characteristics of irrigation and drainage facilities. The objective of this program is to manage the ledger of each facilities and to scan the characteristics of facilities. Telemeter(TM) system, the second component, monitors and processes the data from the sensors statistically. This system is preprogramed for the complete design of TC/TM system. Hydrological Data Management(HDM) system, the third component, executes the hydrological analysis using meteorological data. The unified management system can provide the latest information, such as image data, lists and items of facilities, and items of reforming and rebuilding etc., of the facilities to the manager. At the same time, this system can manage hydrological and meteorological data in realtime.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.75-78
• /
• 2004

In an optical disk drive, a feeding system which is used to move the optical pick-up system to the target position and the proper control scheme of it are important in random access performance. Since the effect of control is directly affected by the modeling precision of the real system, the precise modeling to the real system should be acquired. Although a simple linear order modeling to the feeding system of an optical disk drive is useful in understanding of the overall dynamic characteristics, the dynamic characteristics which are belongs to the nonlinear area cannot be predicted correctly. Furthermore, the feeding system of an optical disk drive has many nonlinear characteristics such as a nonlinear friction and backlash. For this reason, the understanding of the nonlinear properties in the feeding system is very important. In this paper, the nonlinear items of the feeding system, friction and backlash, are introduced and the effect of it are investigated. Finally, the mathematical model considering the nonlinear properties is compared to the real system, and some comments of it are given.

• Journal of the Korean Solar Energy Society
• /
• v.35 no.3
• /
• pp.49-56
• /
• 2015

This paper presents a comparative operating characteristics of static var compensator(SVC) and static synchronous compensator(STATCOM) for compensating the reactive power in the Jeju power system. There are two kinds of reactive power compensating systems, which are active and passive system in the applications of the line commutated converter type high voltage direct current (LCC-HVDC). In the Jeju power system, two STATCOMs as active compensating system have been operating. Even though STATCOM has good performance compared with SVC, economical efficiency of former system is not good to the latter system. So, it is necessary to examine the performance and economical efficiency depend on the intention before appling the system. To compare the operating characteristics of two systems in the Jeju power system, simulations have been carried out for case studies that both of the HVDC system have transient state by using PSCAD/EMTDC program.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.644-654
• /
• 2013

It is required for enterprises to construct the proper information management system in order to cope with the volatile business situations. The mobile office system is introduced from the needs to provide organization members smart information and mobility. By setting the model, hence, we intend to scrutinize the impact of the task-technology fit model and organizational characteristics of the mobile office system on the job performance. As a result, system quality, information quality and mobility are revealed to affect positively the task-technology fitness and the fitness also affects the job performance positively. Organization characteristics affects the job performance positively through the task-technology fitness, too. Therefore the organization which plans to introduce the mobile office system should consider the task-technology fitness and exert organizational-level efforts to adopt and use the mobile office system in the workplace.

• Journal of Drive and Control
• /
• v.13 no.3
• /
• pp.8-14
• /
• 2016

This study describes the effect of the critical pressure ratio of a control valve on the performance of an air spring system composed of an air spring, auxiliary chamber, control valve and mass in order to suggest a more efficient design for an air spring system. The critical pressure ratio of the control valve is assumed to have a fixed value, but the critical pressure ratio of the control valve is known to have various values between 0.05 and 0.6, and the effect of the variation of the critical pressure ratio on the performance of the air spring system has not yet been reported. The analysis derives nonlinear and linear governing equations of the air spring system, including the critical pressure ratio of the control valve. This simulation study is presented to show that the impedance and transmissibility characteristics of the air spring system change due to variations in the critical pressure ratio of the control valve as well as its sonic conductance. As a result, the critical pressure ratio of the control valve should be maintained as large as possible to improve the vibration isolation characteristics of the air spring system.

• International Journal of Automotive Technology
• /
• v.4 no.1
• /
• pp.31-40
• /
• 2003

W-beam guardrail system has been the most popular roadside safety device around the world. Through large plastic deformation and corresponding energy dissipation, a W-beam guardrail system contains and re-directs out-of-control vehicles so as to reduce the impact damage on the vehicle occupants and the vehicles themselves. In this paper, our recent experiments on 1 : 3.75 downscaled W-beam and the beam-post system are reported. The static and impact test results on the load characteristics, the global response and the local cross-sectional distortion are reveled. The effects of three different end-boundary conditions for the beam-only testing are examined. It is found that the load characteristics are much dependent on the combined contribution of the local cross-sectional distortion and the end-supporting conditions. The energy Partitioning between the beam and the supporting Posts in the beam-Post-system testing were also examined. The results showed that the energy dissipation partitioning changed with the input impact energy. Finally, a simple mass-spring model is developed to assess the dynamic response of a W-beam guardrail system in response to an impact loading. The model's prediction agrees well with the experimental results.

• The Journal of Information Systems
• /
• v.27 no.3
• /
• pp.25-42
• /
• 2018

Purpose The purpose of this study focused on adopting production systems in cognitive psychology to improve the extraction process of persuasive design characteristics for healthcare-related mobile applications. Design/Methodology/Approach A research approach with four stages was developed. We developed and updated the evaluation guideline for persuasive design characteristics (PDC). We tried to summarize and analyze each of 28 PDC and prepared related production rules. Verification process for both guideline approach and production system approach were performed. Top one hundred apps from both medical category and health and Fitness category were selected and evaluated by two approaches. By comparing the results of the two approaches, we tried to explain the improvement and reliability of introducing the production system in the PDC extraction process. Findings Based on the updated guideline for healthcare-related mobile applications, a production system in cognitive psychology was developed. By comparing the PDC extraction results by two approaches, production system showed a better improvement for evaluation precision and efficiency for decision-making process. The findings of this study can be used for researchers and app developers to apply production system to analyze, evaluate, and develop better healthcare-related apps with persuasion.