• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.11
• /
• pp.943-954
• /
• 2000

Fieldbus is the lowest level industrial network in the communication hierarchy of factory automation and distributed process control systems. Data generated from field devices are largely divided into three categories : time-critical, periodic and time-available data. Because these data share one fieldbus medium, it needs a method that allocates these data to the bandwidth-limited fieldbus medium. This paper introduces an implementation method of bandwidth allocation scheme on PROFIBUS. In order to implement bandwidth allocation scheme on PROFIBUS, the following functions need to be supplemented on the FDL(Fieldbus Datalink Layer) protocol: (i) separation of medium bandwidth into periodic and non-periodic intervals, (ii) synchronization of node timers over a local link. In order to examine the validity of bandwidth allocation scheme on PROFIBUS, this paper develops an experimental model of a network system. The results obtained from the experimental model show that the bandwidth allocation scheme satisfies the performance requirement of time-critical, periodic and time-available data.

• Journal of Communications and Networks
• /
• v.16 no.6
• /
• pp.667-676
• /
• 2014

Connectivity is a crucial quality of service measure in wireless sensor networks. However, the network is always at risk of being split into several disconnected components owing to the sensor failures caused by various factors. To handle the connectivity problem, this paper introduces an in-advance mechanism to prevent network partitioning in the initial deployment phase. The approach is implemented in a distributed manner, and every node only needs to know local information of its 1-hop neighbors, which makes the approach scalable to large networks. The goal of the proposed mechanism is twofold. First, critical nodes are locally detected by the critical node detection (CND) algorithm based on the concept of maximal simplicial complex, and backups are arranged to tolerate their failures. Second, under a greedy rule, topological holes within the maximal simplicial complex as another potential risk to the network connectivity are patched step by step. Finally, we demonstrate the effectiveness of the proposed algorithm through simulation experiments.

• Journal of Internet Computing and Services
• /
• v.9 no.4
• /
• pp.79-84
• /
• 2008

In these days, many organizations try to manage their assets in safe way due to fast change in information-communication environment. In Korea, risk analysis and vulnerability analysis for security improvement of critical asset is booming by enforcement of Act on security of information and communication infrastructure. It is obligate that each critical information infrastructure needs to get vulnerability analysis. In this paper, we proposed Object Oriented Asset Classification model for asset analysis and risk analysis.

• Nuclear Engineering and Technology
• /
• v.42 no.5
• /
• pp.520-545
• /
• 2010

This paper presents the neutronics modeling capabilities of the fast reactor simulation system SHARP, which ANL is developing as part of the U.S. DOE's NEAMS program. We discuss the three transport solvers (PN2ND, SN2ND, and MOCFE) implemented in the UNIC code along with the multigroup cross section generation code $MC^2$-3. We describe the solution methods and modeling capabilities, and discuss the improvement needs for each solver, focusing on massively parallel computation. We present the performance test results against various benchmark problems and ZPR-6 and ZPPR critical experiments. We also discuss weak and strong scalability results for the SN2ND solver on the ZPR-6 critical assembly benchmarks.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.10a
• /
• pp.527-530
• /
• 2004

This paper presents an optimization formulation for resource scheduling in Critical Resource Diagramming (CRD) of production scheduling networks. A CRD network schedules units of resources against points of needs in a production network rather than the conventional approach of scheduling tasks against resource availability. This resource scheduling approach provides more effective tracking of utilization of production resources as they are assigned or 'moved' from one point of need to another. Using CRD, criticality indices can be developed for resource types in a way similar to the criticality of activities in Critical Path Method (CPM). In our supply chain model, upstreams may choose either normal operation or expedited operation in resource scheduling. Their decisions affect downstream's resource scheduling. The suggested optimization formulation models resources as CRD elements in a production two-stage supply to minimize the total operation cost

• Journal of the Korean Applied Science and Technology
• /
• v.18 no.4
• /
• pp.249-253
• /
• 2001

A proposed method of determining the composition of mixed micelles in equilibrium with monomer of known composition is described. The systems were sodium ${\alpha}-sulfonated$ dodecanoyl ethyl esther (${\alpha}-SR_{12}Et$) or sodium dodecyl sulfate(SDS)-polyoxyethylene 23 lauryl ether (Brij 35) un water and in 0.1M sodium chloride solution at $25^{\circ}C$. This technique applies the Gibbs-Duhem equation to the mixed micelles, which is treated as a pseudophase. This proposed methodology, which needs only critical micelle concentration data as a function of monomer composition, is applied to an anionic/nonionic surfactant pair. The calculated monomer-micelle equilibrium is found to be very similar to the much-used regular solution for nonideal systems.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.555-557
• /
• 2003

As electric power transmission systems grow to supply the increasing electric power demand, transmission capacity is larger. but that's really difficult to secure the location for power transmission and distribution to user. The high temperature superconducting(HTS) cable is a method to solve this problem. But for applying to real systems, it needs to investigate the effect of HTS cable. The most important things is the investigation of fault condition. the fault on HTS cable include the quench state. When a fault occur in a circuit, three critical parameters(temperature, current density, magnetic field) exist. when one of these parameters exceeds the critical value, the superconducting becomes normal-conducting. f the cooling power is insufficient to recover the superconducting state, the normal-conducting zone expands. In order to solve these problem, this paper present simulate the quench state considering the over-current and over-voltage in the informal circuit and analyze the quench state.

• Journal of Korean Critical Care Nursing
• /
• v.11 no.3
• /
• pp.35-44
• /
• 2018

Purpose : This study investigates pediatric nurses' knowledge and attitudes regarding iatrogenic narcotic analgesic withdrawal symptoms management (INAWSM). Methods : In this cross-sectional study, 253 pediatric nurses working at a tertiary hospital in Seoul participated. Instruments were the inventory consisting questionnaires on 35 items knowledge and 12 items attitude for INAWSM. Further, descriptive statistics, t-test, and analysis of variance were used to evaluate the nurses' knowledge and attitudes. Results : The correct answers rate of knowledge toward INAWSM was 44.9%. With respect to the pediatric nurses' attitudes, the participants scored an average value of $2.83{\pm}0.25$ out of 4 points. The factor related to the knowledge and attitude level was age, pediatric nursing experience, educational experience, and educational needs. Conclusions : Results revealed that pediatric nurses had inadequate knowledge and attitude on INAWSM despite a compulsory education. Therefore, it is necessary to develop an efficient INAWSM educational program.

• Journal of the military operations research society of Korea
• /
• v.36 no.1
• /
• pp.1-13
• /
• 2010

Defense expenditure is the investment for national defense capabilities acquisitions based on the national competitiveness, and includes research and development budgets more than some fixed ratio. So we need to guarantee the defense research and development budgets for National Defense Reform 2020 to posture that correspond to the future warfare, to acquire advanced weapon systems and critical technologies effectively. Especially advancement of the defense technology capabilities for future warfare is one of the issues that we are faced, and it needs to be researched and interested continuously. In this paper, we analysed 16 nation`s defense expenditures growth patterns and defense S&T indices, and proposed the needs of the guaranteed funding at the fixed ratio for defense S&T development.

• Korean Journal of Applied Biomechanics
• /
• v.12 no.2
• /
• pp.407-415
• /
• 2002

Athletic products must meet the needs of athletes and the demands imposed by sports through innovative design. These needs of athletes and requirements of sports are performance, protection and comfort related. In depth knowledge of anatomy and physiology, etiology of commonly reported injuries, and lower extremity mechanics form the basis of product creation/engineering. Game analysis which entails time and frequency surveys of the skills performed during a game, interviews with athletes and coaches, and discussions with medical staffs are used to identify the skills that are critical to the needs of athletes. In lab full biomechanical analyses of these skills and/or physiological responses of the athletes lead to clear functional criterions that serve as guidelines to be met by the design team. The concepts created by the design team are in turns subjected to the same battery of biomechanical analyses. The learning gathered through this pluridisciplinary process is used to further evolve design concepts. The evolution-testing loop is repeated until biomechanical and/or physiological, mechanical and perceptual tests indicate that the design concept meets the established functional design criterions. At that time, the design concepts is ready for manufacturing research and development. Additional biomechanical and physical tests are performed through that phase to confirm that the manufacturing processes preserve the functionality of the design concept. Durability and long term performance of production samples are evaluated through a final three month long weartest program. A rigorous research/testing program is crucial to create and engineer sport products that meet the performance, protection.