• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.89-100
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• 2022

With the advancement in the Internet of things Technology (IoT) cloud computing, billions of physical devices have been interconnected for sharing and collecting data in different applications. Despite many advancements, some latency - specific application in the real world is not feasible due to existing constraints of IoT devices and distance between cloud and IoT devices. In order to address issues of latency sensitive applications, fog computing has been developed that involves the availability of computing and storage resources at the edge of the network near the IoT devices. However, fog computing suffers from many limitations such as heterogeneity, storage capabilities, processing capability, memory limitations etc. Therefore, it requires an adequate task scheduling method for utilizing computing resources optimally at the fog layer. This work presents a comprehensive review of different task scheduling methods in fog computing. It analyses different task scheduling methods developed for a fog computing environment in multiple dimensions and compares them to highlight the advantages and disadvantages of methods. Finally, it presents promising research directions for fellow researchers in the fog computing environment.

• Advances in aircraft and spacecraft science
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• v.9 no.5
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• pp.479-491
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• 2022

This work concerns the investigation of a Q1D methodology employed to study pressure oscillations in solid rocket motors driven by hydrodynamic instabilities. A laboratory-scale solid motor designed to develop vortex-shedding phenomena is analyzed for the whole firing time. The comparison between numerical results and experimental data shows good agreement regarding pressure oscillations signature, especially in the flute-mode behavior, the typical oscillations frequency trend present in any motor liable to hydrodynamic instabilities. Such result ensures the model capability to cope with this particular kind of pressure oscillations source, allowing the investigation of the phenomenon with a lighter and cost savings methodology than CFD simulations.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.147-152
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• 1995

During transients or major upsets, operators of a nuclear power plant are faced with a significant amount of information which oftentimes exceeds their capability of processing information in such a time-critical situation. To help resolve this problem of information overload, considerable work is underway worldwide to improve its man-machine interface systems (MMISs). The I&C research team of KAERI is developing a DYNamic Alarm processing System, called DYNAS, to suppress unnecessary or nuisance alarms, and at the same time, emphasize vital information. This paper describes our basic strategy to process alarms in DYNAS.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2356-2365
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• 2023

Characterization, dismantling and pre-disposal management of irradiated graphite (i-graphite) have an important role in safe decommissioning of several nuclear facilities which used this material as moderator and reflector. In addition to common radiation protection issues, easily volatizing long-lived radionuclides and stored Wigner energy could be released during imprudent retrieval and processing of i-graphite. With this regard, among all cutting technologies, abrasive waterjet (AWJ) can successfully achieve all of the thermo-mechanical and radiation protection objectives. In this work, factorial experiments were designed and systematically conducted to characterize the AWJ processing parameters and the machining capability. Moreover, the limitation of dust production and secondary waste generation has been addressed since they are important aspects for radiation protection and radioactive waste management. The promising results obtained on non-irradiated nuclear graphite blocks demonstrate the applicability of AWJ as a valid technology for optimizing the retrieval, storage, and disposal of such radioactive waste. These activities would benefit from the points of view of safety, management, and costs.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.147-149
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• 2015

A nuclear power plant construction project normally involves a large construction work of which the total project cost is over 5 trillion Won, Such a large-scale construction project has the risks of schedule delay and quality degradation due to increase in project cost, because designs are changed due to design errors. The reasons for design changes during installation are 1) insufficient engineering capability of the owner, 2) information discontinuance due to the multiple package method, and 3) inefficient constructability review processes. Accordingly, this study proposes, through problem analysis, a method of developing a constructability review system that utilizes constructability review processes and a data-based technology (3D modeling) that are optimized for nuclear power plant construction projects. It also presents a method of establishing a system for reviewing constructability in which constructability review processes and a Database (3D model, Schedule, Design change Items) are linked each other.

• Journal of KIISE:Information Networking
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• v.33 no.3
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• pp.257-268
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• 2006

In this paper, we have designed and implemented mobile instant messenger which has extensible presence service capability. Most previous work on instant messaging system has some limitation with regard to interoperability and extensibility. To solve these problems, we have employed the presence service architecture of IETF. In order to provide extensible presence capability in the wireless mobile communication, we have employed the presence service attributes which are defined in OMA's IMPS architecture. In particular, we have designed and implemented the presence service libraries for manipulating the presence information in response to user's requirement. finally, we have developed the wireless E-mail service, employing the presence service architecture, to verity the extensibility.

• IE interfaces
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• v.25 no.1
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• pp.52-63
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• 2012

Up-to-date enlargement of the scale of global outsourcing has brought about the need of systematic and efficient tools for competitive supplier discovery located in various areas. A web-based business supporting system, referred to as Excellent Manufacturer Scouting System(EMSS), is being developed to serve core business functions including supplier discovery, negotiation, and collaboration between overseas buyers and domestic suppliers throughout the process of supply chain formation. In this paper, a supplier assessment model devoted to evaluation of core manufacturing capability is proposed by targeting small and medium sized mold companies. The assessment model will eventually be loaded to EMSS. Even if many well-designed models for supplier assessment have been presented in literature, most of them limit the evaluation criteria to somewhat general information on a given supplier, such as cost, delivery time, quality, rather than core manufacturing capability itself. This research is pioneering work on supplier assessment from the viewpoint of manufacturability. The proposed assessment model classifies assessment indices into six criteria, which have been drawn by intensive survey and analysis of the mold industry. Actual assessment indices for each criterion are also presented along with an exemplary evaluation result.

• Carbon letters
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• v.17 no.1
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• pp.39-44
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• 2016

The work presented in this report was a detailed comparative study of the electrochemical response exhibited by graphite anodes in Li-ion batteries having different physical features. A comprehensive morphological and physical characterization was carried out for these graphite samples via X-ray diffraction and scanning electron microscopy. Later, the electrochemical performance was analyzed using galvanostatic charge/discharge testing and the galvanostatic intermittent titration technique for these graphite samples as negative electrode materials in battery operation. The results demonstrated that a material having a higher crystalline order exhibits enhanced electrochemical properties when evaluated in terms of rate-capability performance. All these materials were investigated at high C-rates ranging from 0.1C up to 10C. Such improved response was attributed to the crystalline morphology providing short layers, which facilitate rapid Li⁺ ions diffusivity and electron transport during the course of battery operation. The values obtained for the electrical conductivity of these graphite anodes support this possible explanation.

• Journal of the Korean Electrochemical Society
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• v.3 no.2
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• pp.72-75
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• 2000

For the purpose of developing the non-stoichiometric Zr-based Laves phase alloy with higher capacity and better performance for electrochemical application, extensive work has been carried out in KAIST. After careful alloy design of $ZrMn_2-based$ hydrogen storage alloys through varing their stoichiometry while susbstituting or adding some alloying elements, the $Zr-Ti-(Lh-V-Ni)_{2.2},\;Zr-Ti-(Mn-V-Cr-Ni)_{1.8\pm0.1}$ with high capacity and better performance was developed. Consequently the $Zr-Ti-(Mn-V-Ni)_{2.2}$ alloy has a high discharge capacity of 394mAh/g and shows a high rate capability equaling to that of commercialized $AB_5$ type alloys. On the other hand, in order to develop the hydrogen storage alloy with higher discharge capacity, the hypo-stoichiometric $Zr(Mn-V-Ni)_{2-\alpha}$ alloys substituted by Ti are under developing. As the result of competitive roles of Ti and $stocihiometry({\alpha})$, the discharge capacity of $Zr-Ti-(Mn-V-Cr-Ni)_{l.8\pm0.1}$ alloys is about 400mAh/g(410 mAh/g, which shows the highest level of performance in the Zr-based alloy developed. Our sequential endeavor is improving the shortcoming of Zr-based Laves phase alloy for commercialization, i.e., poor activation property and low rate capability, etc. It is therefore believed that the commercialization of Zr-based Laves phase hydrogen storage alloy for Ni-MH rechargeable battery is in near future.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, $50-80\%$ of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, Improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.