• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.3
• /
• pp.975-985
• /
• 2013

In this research, the integrated modeling system by coupling of a watershed model, a reservoir model, and a river model has been constructed in Doam reservoir watershed. Because of domestic climate characteristics, it is inevitable to construct the dam for control of flood, water use, and power production due to the heavy rain in the summer. Especially, when the dam is constructed on the stream for these kinds of purpose, it is necessary to consider this region as one watershed and also to make the integrated system for simulation and management. In this study, SWAT model was constructed for watershed modeling and EFDC-WASP model was constructed for simulating the hydrodynamic and water quality of the reservoir and the downstream in Doam dam watershed. Also, the water quality improvement equipment for demonstration was applied in the upstream part of Doam reservoir, which shows the applicability of the developed integrated modeling system.

• Nuclear Engineering and Technology
• /
• v.56 no.3
• /
• pp.866-872
• /
• 2024

Design Extension Conditions (DEC)-A assessments of the operating nuclear power plants are generally considered for the purpose of getting additional safety demonstrations of their capability to undergo conditions that are generally more severe than DBAs by features implemented in the design and accident management measures. The pursued methodology is generally based upon Best Estimate approaches aiming at verifying that the safety limits in terms of integrity of the barriers against eventual large or early releases of radioactive material are fulfilled. These aspects are nowadays being experimentally and analytically addressed within the OECD/NEA experimental projects like the ATLAS and PKL series where a set of DEC-A experiments are considered. In this paper, experiments related to SBLOCA at the vessel upper head of the pressurized vessel of ATLAS and PKL are analytically assessed using the CATHARE code. These experiments includes issues related to common cause failure of the safety injection system and operator actions for preventing core excessive overheating. It is shown that, on the one hand, the safety features embedded in the design together with the operator actions are capable to prevent the progression towards a severe accident state and on the other hand, the code prediction capabilities for such scenario are generally good but still to be enhanced.

• Smart Media Journal
• /
• v.13 no.1
• /
• pp.52-59
• /
• 2024

This paper proposes a plan to improve the reception radio environment of the mobile terminal and maintain a constant reception electric field by using small cells in a small closed environment. In order to configure an efficient communication infrastructure for small cells, both ends of wireless transmission and reception of an Ethernet-based wireless video recording system are connected using an L2 switch. The small cell connected to the receiving side L2 switch shares the wireless network section of the wireless video recording system and connects to the transmitting side L2 switch. After that, when it is normally linked to FMS, a management system for small cells, through the Internet network, the output of small cells is checked. In order to verify the results, a proposed network is formed on the elevator inside the building with a poor radio wave environment, and the radio wave environment is measured before and after the small cell application in the section where the elevator operates. As a result, the main parameters of the radio wave environment in all sections of the elevator are improved, as well as a constant receiving electric field strength within the moving elevator.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.4
• /
• pp.1884-1903
• /
• 2019

Device-to-Device (D2D) communications can provide proximity based services in the future 5G cellular networks. It allows short range communication in a limited area with the advantages of power saving, high data rate and traffic offloading. However, D2D communications may reuse the licensed channels with cellular communications and potentially result in critical interferences to nearby devices. To control the interference and improve network throughput in overlaid D2D cellular networks, a novel channel assignment approach is proposed in this paper. First, we characterize the performance of devices by using Poisson point process model. Then, we convert the throughput maximization problem into an optimal spectrum allocation problem with signal to interference plus noise ratio constraints and solve it, i.e., assigning appropriate fractions of channels to cellular communications and D2D communications. In order to mitigate the interferences between D2D devices, a cluster-based multi-channel assignment algorithm is proposed. The algorithm first cluster D2D communications into clusters to reduce the problem scale. After that, a multi-channel assignment algorithm is proposed to mitigate critical interferences among nearby devices for each D2D cluster individually. The simulation analysis conforms that the proposed algorithm can greatly increase system throughput.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.5
• /
• pp.225-234
• /
• 2015

Nowadays a Virtual Power Plant (VPP) represents an aggregation of distributed energy resource such as Distributed Generation (DG), Combined Heat and Power generation (CHP), Energy Storage Systems (ESS) and load in order to operate as a single power plant by using Information and Communication Technologies, ICT. The VPP has been developed and verified based on a single virtual plant platform which is connected with a number of various distributed energy resources. As the VPP's distributed energy resources increase, so does the number of data from distributed energy. Moreover, it is obviously inefficient in the aspects of technique and cost that a virtual plant platform operates in a centralized manner over widespread region. In this paper the concept of the large-scale VPP which can reduce a error probability of system's load and increase the robustness of data exchange among distributed energy resources will be proposed. In addition, it can directly control and supervise energy resource by making small size's virtual platform which can make a optimal resource scheduling to consider of variable and sensitive load in the large-scale VPP. It makes certain the result is verified by simulation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.7 no.1
• /
• pp.1-9
• /
• 2014

Fireworks are used in our country, most of U.S. equipment and software systems are old and outdated technology. If the Fireworks receives a signal, then the start of the pre-placed as the signal proceeds to the middle of a problem with the site manager directly turn off the power and turn on again. Manager, where it should be handled directly. So, in this paper, we researched a domestically developed technology to escape the reality that relies on foreign technology. Our technology should be suited the convenience, reliability and lower cost. This technology can generate revenue from overseas.

• Journal of Drive and Control
• /
• v.21 no.2
• /
• pp.15-22
• /
• 2024

The objective of this study was to examine whether a gerotor pump used in a transmission could be converted into an electric vehicle thermal management system pump using a virtual design environment. To achieve this objective, we first built an environment that could analyze the performance of a gerotor pump in heat transfer fluid. Flow rate, pressure, and volumetric efficiency were then analyzed when using heat transfer fluid in a gerotor pump. Finally, how large the displacement volume of the pump should be designed when using a heat transfer fluid other than oil was determined. Based on results of this study, it is expected that gerotor pumps will be applied to new business fields such as electric vehicle cooling systems.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.4
• /
• pp.1481-1500
• /
• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.41 no.4
• /
• pp.22-33
• /
• 2018

Recently domestic manufacturing companies have been experiencing worsening profitability and stunted growth due to the long-term economic recession and the rapid rise of developing countries such as China and Southeast Asia. These difficulties force many companies to concentrate their core competencies on new value creation and innovation in order to gain momentum for new growth. Enterprise Resource Planning (ERP) has been considered as one of viable solutions. Among the various modules in ERP, shop floor control function in the production management module is rather limited. In order to overcome this problem, Manufacturing Execution System (MES) has been used as a subsystem which has a strong information gathering power and flexibility. Both systems interact closely with each other. In particular, ERP requires fast, accurate shop floor information at MES. This paper describes how to synchronize relevant information between ERP and MES with theory of constraints (TOC). The processing time information transmitted from the MES workplace is received at the ERP workplace. In the process, the received processing time is causing information distortion in ERP, when the information gathering standard of MES is different from the ERP information interpretation standard. The Drum-Buffer-Rope theory of TOC was applied to resolve this problem, therefore, information synchronization between both systems was made. As a precondition, the standard time of the upper ERP system was rearranged according to the capacity constraints resource. As a result, standard time restructuring has affected changes in labor costs. Standard labor costs have come close to actual ones, and information synchronization of MES transmission data has improved the reliability of standard product costs, such that it enabled various company-wide restructuring actions to be much more effective.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.10
• /
• pp.1381-1390
• /
• 2021

Smart grid is a representative convergence new technology in the era of the 4th industry revolution that deals with three broad security areas consisting of control system, the power grid, and the consumer. As it is a convergence new technology of the 4th industrial society, it is true that it can have a positive effect on the country's technological development, growth engine, and economic feasibility in the future. However, since the smart grid is expected to cause enormous damage in the event of a security accident, energy-related organizations must prepare various security measures to predict and respond to the latest security incidents. In this paper, the current status of domestic and foreign smart grids, trends in security standards, vulnerabilities and threats, and prospects for smart grid security technologies are to be considered.