• Resources Recycling
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• v.22 no.3
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• pp.65-72
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• 2013

A vertical column pneumatic separator was modified to improve its separation performance. A branch column was installed at the center of the main column, which created a bypass flow and changed the flow rate of the main column before and after the branch column. To separate a mixture comprising light and heavy materials, the airflow in main column after the branch column was set to lift the only light materials and the airflow in main column before the branch column was set to prevent the flow of the light materials from flowing downwards. Materials directed into the branch column were separated from the flow and returned to the feeder through the cyclone linked to the branch column. The performances of the straight-type separator and the modified separator were compared using glass and zirconia beads with a narrow size distribution.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2327-2335
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• 2018

Fluid catalytic cracking (FCC) is an important chemical process that is widely used to produce valuable petrochemical products by cracking heavier components. However, many difficulties exist in modeling the FCC process due to its complexity. In this study, a dynamic process model of a FCC process is suggested and its structural observability is analyzed. In the process modeling, yield function for the kinetic model of the riser reactor was applied to explain the product distribution. Hydrodynamics, mass balance and energy balance equations of the riser reactor and the regenerator were used to complete the modeling. The process model was tested in steady-state simulation and dynamic simulation, which gives dynamic responses to the change of process variables. The result was compared with the measured data from operating plaint. In the structural analysis, the system was analyzed using the process model and the process design to identify the structural observability of the system. The reactor and regenerator unit in the system were divided into six nodes based on their functions and modeling relationship equations were built based on nodes and edges of the directed graph of the system. Output-set assignment algorithm was demonstrated on the occurrence matrix to find observable nodes and variables. Optimal locations for minimal addition of measurements could be found by completing the whole output-set assignment algorithm of the system. The result of this study can help predict the state more accurately and improve observability of a complex chemical process with minimal cost.

• Earthquakes and Structures
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• v.15 no.6
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• pp.639-654
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• 2018

Rocking motion have been used for achieving the 'resilient buildings' against earthquakes in recent studies. Low-rise buildings, unlike the tall ones, because of their small aspect ratio tend to slide rather than move in rocking mode. However, since rocking is more effective in seismic response reduction than sliding, it is desired to create rocking motion in low-rise buildings too. One way for this purpose is making the building's structure rock on its internal bay(s) by reducing the number of bays at the lower part of the building's skeleton, giving it a mushroom form. In this study 'mushroom skeleton' has been used for creating multi-story rocking regular steel buildings with square plan to rock on its one-by-one bay central lowest story. To show if this idea is effective, a set of mushroom buildings have been considered, and their seismic responses have been compared with those of their conventional counterparts, designed based on a conventional code. Also, a set of similar buildings with skeleton stronger than code requirement, to have immediate occupancy (IO) performance level, have been considered for comparison. Seismic responses, obtained by nonlinear time history analyses, using scaled three-dimensional accelerograms of selected earthquakes, show that by using appropriate 'mushroom skeleton' the seismic performance of buildings is upgraded to mostly IO level, while all of the conventional buildings experience collapse prevention (CP) level or beyond. The strong-skeleton buildings mostly present IO performance level as well, however, their base shear and absolute acceleration responses are much higher than the mushroom buildings.

• Journal of Arbitration Studies
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• v.27 no.4
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• pp.179-198
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• 2017

The OECD Guidelines for Multinational Enterprises (The Guidelines) was initially promulgated in 1976 as a form of annex to the OECD Declaration on International Investment and Multinational Enterprises. The Guidelines aims at accomplishing the implementation and dissemination of the Responsible Business Conduct. The latest version of The Guidelines, as revised in 2011, directed 47 adhering countries to The Guidelines to set up their respective National Contact Points (NCPs). NCPs are The Guidelines' dispute resolution mechanism for specific instances arising from breach by multinational enterprises of The Guidelines. Korea to date has its own NCP performing its role to offer good offices and facilitates settlement between the parties to the specific instances regarding The Guidelines. However, there has been strong criticism from NGOs and civil society that Korea NCP has not performed well due to lack of transparency and impartiality, especially in the context of the governance of Korea NCP. Under this circumstance, this paper ⅰ) examines current status and problems of Korea NCP, ⅱ) evaluates the core criteria for function and governance of NCPs through a comparative overseas cases study, and ⅲ) suggests improvement plans for Korea NCP.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.3
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• pp.151-166
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• 1994

The manufacturing environment on which this research is focused is an FMS in which AGVs are used for material handling and each part type has one or more process plans. The research aims at developing a methodology whereby, given a part and volume mix for production during any production session, the best set of process plans including one plan per part type is selected and the best unidirectional AGV guidepath can be dynamically reconfigured in response to changes in parts and lot sizes combination. For the integrated PPS/FGD problem in which two functions of process plan selection (PPS) and flexible AGV guidepath design (FGD) are integrated, a zero-one integer programming model is developed. The integrated problem is decomposed into two subproblems, process plan selection given a directed AGV layout and AGV guidepath design with a fixed process plan per part type. A heuristic algorithm that alternately and iteratively solves these two subproblems is developed. The effectiveness of the heuristic algorithm is tested by solving various randomly generated sample problems and comparing the heuristic solutions with those obtained by an exact procedure. From the test results, the following conclusions are drawn: 1) For a reasonable size problem, the heuristic is very effective. 2) By integrating the two functions of PPS and FGD, a remarkable benefit in total production time for a given part and volume mix is gained.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1252-1273
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• 2011

In Web Service Composition (WSC) area, services selection aims at selecting an appropriate candidate from a set of functionally-equivalent services to execute the function of each task in an abstract WSC according to their different QoS values. In despite of many related works, few of previous studies consider transactional constraints in QoS-aware WSC, which guarantee reliable execution of Composite Web Service (CWS) that is composed by a number of unpredictable web services. In this paper, we propose a novel global selection-optimal approach in WSC by considering both transactional constraints and end-to-end QoS constraints. With this approach, we firstly identify building rules and the reduction method to build layer-based Directed Acyclic Graph (DAG) model which can model transactional relationships among candidate services. As such, the problem of solving global optimal QoS utility with transactional constraints in WSC can be regarded as a problem of solving single-source shortest path in DAG. After that, we present Graph-building algorithms and an optimal selection algorithm to explain the specific execution procedures. Finally, comprehensive experiments are conducted based on a real-world web service QoS dataset. The experimental results show that our approach has better performance over other competing selection approaches on success ratio and efficiency.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.151-155
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• 2001

Mobile agent technology has been the subject of much attention in the last few years, mainly due to the proliferation of distributed software technologies combined with the distributed AI research field. In this paper, we present a design of communication networks of agents that cooperate with each other for forwarding messages to the specific mobile agent in order to make the overall system location transparent. In order to make the material accessible to general intelligent system researchers, we present the general ideas abstractly in terms of the graph theory. In particular, a proxy network is defined as a directed acyclic graph satisfying some structural conditions. In turns out that the definition ensures some kind of reliability of the network, in the sense that as long as at most one proxy agent is abnormal, there agent exists a communication path, from every proxy agent to the target agent, without passing through the abnormal proxy. As the basis for the implementation of this scheme, an appropriate initial proxy network is specified and the dynamic nature of the network is represented by a set of graph transformation rules. It is shown that those rules are sound, in the sense that all graphs created from the initial proxy network by zero or more applications of the rules are guaranteed to be proxy networks. Finally, we will discuss some implementation issues.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.49
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• pp.167-188
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• 2011

The World Customs Organization (WCO) has designed standards to secure and to facilitate the ever-growing flow of goods in international commerce since 9.11 terrorism in U.S.A. These standards are set forth in the SAFE Framework of Standards, which was adopted by the WCO Council at its 2005 Sessions and the SAFE Framework incorporates the concept of the Authorized Economic Operator (AEO), and the Council directed the WCO to develop more detailed implementing provisions for the AEO concept. It is considered to be reliable in customs-related operations and ensures an equivalent level of protection in customs controls for goods brought into or out of the customs territory, whereas it is difficult for many Korean companies to make a decision of introducing the AEO certification programs because of a lack of cost and benefit information. In this article, We have reviewed the definition and the developing status of an AEO programmes and have studied the benefit and expected effect through documentary research methods. Therefore, it is essential for Korean companies to be certified the AEO programmes from Korea customs service for increasing security in international supply chains through risk management and customs compliance, in addition, the key-driver in the future will be expectations from the business community to work with AEO partners.

• Spatial Information Research
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• v.11 no.4
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• pp.341-358
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• 2003

Korean government has conducted National Geographic Information System(NGIS) project since 1995. The NGIS was set up and directed by central government to stimulate the growth of GIS field in Korea. Thanks to the project, all aspects of GIS in Korea has been rapidly developed. However, this government-led strategy now reveals some limitations on the advancement of GIS in Korea It is time to prepare new approaches for the further development of GIS in Korea. This study aims at introducing the concept and model of National Spatial Data Infrastructure(NSDI) and suggesting strategies fir it. By doing so, this research attempts to reestablish the role of government and draws new policy directions for the NGIS.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.198-205
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• 2020

The purpose of this study is to investigate the effect of real-time remote video instruction using zoom on learners' English reading achievement. The study also sought to identify the efficiency of zoom video lectures and consider supplementing them by surveying learners' opinions and satisfaction regarding zoom video lectures. To this end, control and experimental groups were set up, and two achievement tests and a questionnaire were conducted. The study's results demonstrated that zoom video lectures have a positive effect on learners' English reading achievement. The questionnaire found that learners are satisfied with zoom video lectures for the following reasons: 'increased interest in and motivation towards learning', 'self-directed learning', 'active interaction', 'ease of access', 'ease of information retrieval'. At the same time, the questionnaire also found that some learners are dissatisfied with zoom video lectures due to 'mechanical errors or defects', 'poor audio quality', and 'the need to add customized functions for efficient classes'. In practice, zoom video lectures must be supplemented with automatic attendance processing, convenient data upload and download, and more efficient video screen management. Given the recent increase in online classes, we, as instructors, must develop teaching activities and/or strategies for video lectures that can encourage active participation by learners.