• Journal of the Society of Disaster Information
• /
• v.16 no.4
• /
• pp.813-823
• /
• 2020

Purpose: In order to maximize the stability and productivity of the work through simulation prior to high-risk facilities and high-cost work such as dismantling the facilities inside the reactor, we intend to use digital twin technology that can be closely controlled by simulating the specifications of the actual control equipment. Motion control errors, which can be caused by the time gap between precision control equipment and simulation in applying digital twin technology, can cause hazards such as collisions between hazardous facilities and control equipment. In order to eliminate and control these situations, prior research is needed. Method: Unity 3D is currently the most popular engine used to develop simulations. However, there are control errors that can be caused by time correction within Unity 3D engines. The error is expected in many environments and may vary depending on the development environment, such as system specifications. To demonstrate this, we develop crash simulations using Unity 3D engines, which conduct collision experiments under various conditions, organize and analyze the resulting results, and derive tolerances for precision control equipment based on them. Result: In experiments with collision experiment simulation, the time correction in 1/1000 seconds of an engine internal function call results in a unit-hour distance error in the movement control of the collision objects and the distance error is proportional to the velocity of the collision. Conclusion: Remote decomposition simulators using digital twin technology are considered to require limitations of the speed of movement according to the required precision of the precision control devices in the hardware and software environment and manual control. In addition, the size of modeling data such as system development environment, hardware specifications and simulations imitated control equipment and facilities must also be taken into account, available and acceptable errors of operational control equipment and the speed required of work.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.4
• /
• pp.131-140
• /
• 2013

This paper deals with the design and implementation of an interface for interoperation between DiskSim, a well-known disk simulator, and a system-level simulator based on DEVSim++. Such inter-operational simulation aims at evaluation of an overall performance of storage systems which consist of multiple computer nodes with a variety of I/O level specifications. A well-known system-level simulation framework, DEVSim++ environment is based on the DEVS formalism, which provides a sound semantics of modular and hierarchical modeling methodology at the discrete event systems level such as multi-node computer systems. For maintainability we assume that there is no change of the source codes for two heterogeneous simulation engines. Thus, we adopt a notion of simulators interoperation in which there should be a means to synchronize simulation times as well as to exchange messages between simulators. As an interface for such interoperation DiskSimManager is designed and implemented. Various experiments, comparing the results of the standalone DiskSim simulation and the interoperation simulation using the proposed interface of DiskSimManager, proved that DiskSimManager works correctly as an interface for interoperation between DEVSim++ and DiskSim.

• Journal of Internet Computing and Services
• /
• v.10 no.3
• /
• pp.1-8
• /
• 2009

The primary tasks of a workflow management system specify workflow models with respect to resource, control-flow, data-flow, functional, and operational perspectives, and to enact their workcases (workflow instances). In terms of enacting workflow models, the essential criterion grading the quality of the system is "how much is the system able to guarantee the correctness of workflow models' enactment?". Particularly, the workflow determinacy problem, which may be caused by the interference of the control-flow and the data-flow specifications, is the most challenging issue in guaranteeing the correctness of the system. We are able to solve the problem by either of the following two approaches-analysis of workflow model and verification of workflow enactment. In the paper, we propose a technique that guarantee the system's correctness through verifying workflow enactment. In other words, the technique is able to detect the conflicts of control-flow and data-flow enactments existing on a workflow model, which causes the system to be non-determinant in enacting workflow models. Finally, by applying the technique to the e-Chautauque workflow management system developed by the authors' research group, we prove that the technique is a feasible solution for the workflow determinacy problem.

• Membrane Journal
• /
• v.25 no.4
• /
• pp.301-309
• /
• 2015

Importance of pretreatment for seawater desalination is growing rapidly. Proper selection of pretreatment is critical for the successful, long-term operation in the seawater desalination plant such as seawater reverse osmosis (SWRO). The purposes of seawater pretreatment are to remove particulate, colloidal materials, organic, inorganic materials, microorganisms and their by-products present in the seawater, and thus to improve the performance of seawater desalination systems. However, pretreatment is most challenging for designing and operating seawater desalination plants because of fluctuations of water qualities, site specifications and wide ranges of target materials present in the seawater to be treated. In addition, it is also becoming evident increasingly that microscopic algae are a major cause of operational problems, for example, membrane fouling which is long-standing problem in SWRO process. Pretreatment strategies prior to the operation of seawater desalination technologies should be even more complicated by algae blooms and release of their harmful by-products in marine environment. This paper reviews the roles of various pretreatment methods in seawater desalination process. Benefits and drawbacks are described, which should be taken into account in future studies on selecting pretreatment for seawater desalination process.

• Convergence Security Journal
• /
• v.12 no.6
• /
• pp.11-17
• /
• 2012

Network security performance evaluation is a complex and diverse system environments, a single, specific performance measurements alone performance evaluation measure itself and the meaning of the reliability of the evaluation results do not limit the number of days only. In this paper, we propose a method to measure the security features of security, QoS measurement techniques using MOS satisfaction. MOS(Mean Opinion Score) Rating specifications for network security, QoS satisfaction and how to operate the development and operational model for future customer's satisfaction for information systems that can be used to evaluate the QoS measurement/analysis be utilized in the field. Objectified in the form of standards and performance measurement system provider (supplier development) and consumers(users) all the results available so that how to develop a system. Development is the development of information security features, the performance of these two features networking capabilities and a comprehensive evaluation of a three-gaeyoungyeok Correlating performance measurement methodology. Systematic measurement environment designed using the proposed methodology of this study, when the operating system is on the satisfaction of the security, QoS can be calculated. Forward In addition, a variety of performance metrics and performance measurement methods by extending the network security system satisfaction rating upgrade by the way will be.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.10
• /
• pp.174-180
• /
• 2020

This paper presents the development of a tacho generator that is applicable to a DC motor for anti-aircraft weapon systems. In general, devices such as tacho generators and resolvers are used as feedback devices for controlling DC motors. A tacho generator with a wide operating temperature range was developed, which has robust characteristics against shock loads and vibrations according to the operational characteristics of anti-aircraft weapon systems. The target specifications were set based on the requirements of the tacho generator currently in operation. A rotor coupled to the shaft of the motor and a stator coupled to the housing of the motor were then designed and manufactured. The inductance was 31.0 mH, the terminal resistance was 147.7 ohms, and the rotational measurement factor was satisfactory under both normal operation and operating conditions after the maximum speed for the standard of 9.500 ± 0.475 V/krpm. In addition, the environmental suitability of the applied equipment was confirmed through the rate of change in unit temperature, and it was found that the temperature characteristics were all within 0.03 %/℃.

• Journal of Digital Convergence
• /
• v.16 no.7
• /
• pp.107-116
• /
• 2018

One of the key mission is to develop and prompte the use National Competency Standards, which is defined to be the systemization of competencies(knowledge, skills and attitudes) required to perform duties at the workplace by the nation for each industrial sector and level. This provides the basis for the design of training and detailed specifications for workplace assessment. To promote the data-driven service improvement, the commercial product Splunk was introduced, and has grown to become an extremely useful platform because it enables the users to search, collect, and organize data in a far more comprehensive, far less labor-intensive way than traditional databases. Leveraging Splunk's built-in data visualization and analytical features, HRD Korea have built custom tools to gain new insight and operational intelligence that organizations have never had before. This paper analyzes the NCS homepage. Concretely, applying Splunk in creating visualizations, dashboards and performing various functional and statistical analysis and structure without Web development skills. We presented practical use and implications through case studies.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.9 no.2
• /
• pp.113-119
• /
• 2011

Safe operation and maintenance of engineered dry storage systems for spent fuel from nuclear power plants basically depends on adequately adopted design requirements. The most important design target of the system are those which provide the necessary assurances that spent fuel can be received, handled, stored and retrieved without undue risk to health and safety of workers and the public. To achieve these objectives, the design of the system incorporates features to remove spent fuel residual heat, to provide for radiation protection, and to maintain containment over the lifespan of the system as specified in the design specifications. The features also provide for all possible anticipated operational occurrences and design basis events in accordance with the design basis as guided by the designated regulations. The general performance requirements of a projected storage system are introduced in this paper. The storage system is designed to store fuel assemblies in associated with designated regulatory requirements. Small increases/decreases in maximum burnup can be adjusted with cooling time. These variations are compensated for by a corresponding small site-specific increase/decrease in the design basis-cooling period, as long as the maximum heat load and radioactivity of loaded fuel assemblies are met. Generic design basis events considered for the storage system are summarized. Shielding and radiological requirements along with mechanical and structural are derived in this study.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.5
• /
• pp.516-521
• /
• 2016

In this study, we investigated the operation of railroad fire fighting vehicles against fires on trains in a long railway tunnel. In recent years, long railway tunnels (more than 10 km in length) have been built and the number of such tunnels, such as the Geumjeong tunnel (20.3 km in length) on the Gyeongbu high speed line, Solan tunnel (16.7 km in length) on the Yeongdong line and Yulhyeon tunnel (50.3 km in length) on the Suseo high speed line which is scheduled to be opened in the second half of 2016, is increasing. Significant damage is to be expected, due to the increased evacuation time and limited accessibility of fire services when the train is stopped by an urgent fire in the tunnel. Special fire fighting vehicles capable of running on rails have been developed and operated in overseas advanced countries. Therefore, a fire-response system using Unimog vehicles, which can run on road and rail, instead of road vehicles, is necessary. The characteristics of the railway tunnel and thermal environmental change caused by a train fire in a tunnel were analyzed in this study. Also, the operational requirements of the railroad fire fighting vehicles were evaluated by taking into account the specifications of the railroad fire fighting vehicles under development.

• Journal of the Korea Society for Simulation
• /
• v.29 no.4
• /
• pp.33-46
• /
• 2020

The purpose of Electronic warfare is to disturbe, neutralize, attack, and destroy the opponent's electronic warfare weapon system or equipment. Suppression of Enemy Air Defense (SEAD) mission is aimed at incapacitating, destroying, or temporarily deteriorating air defense networks such as enemy surface-to-air missiles (SAMs), which is a representative mission supported by electronic warfare. This paper develops a simulator for analyzing the effectiveness of SEAD missions under electronic warfare support using C++ language based on the DEVS (Discrete Event Systems Specification) model, the usefulness of which has been proved through case analysis with examples. The SEAD mission of the friendly forces is carried out in parallel with SSJ (Self Screening Jamming) electronic warfare under the support of SOJ (Stand Off Jamming) electronic warfare. The mission is assumed to be done after penetrating into the enemy area and firing HARM (High Speed Anti Radiation Missile). SAM response is assumed to comply mission under the degraded performance due to the electronic interference of the friendly SSJ and SOJ. The developed simulator allows various combinations of electronic warfare equipment specifications (parameters) and operational tactics (parameters or algorithms) to be input for the purpose of analysis of the effect of these combinations on the mission effectiveness.