• Journal of Intelligence and Information Systems
• /
• v.17 no.4
• /
• pp.213-226
• /
• 2011

In global supply chain, the scheduling problems of large products such as ships, airplanes, space shuttles, assembled constructions, and/or automobiles are complicated by nature. New scheduling systems are often developed in order to reduce inherent computational complexity. As a result, a problem can be decomposed into small sub-problems, problems that contain independently small scheduling systems integrating into the initial problem. As one of the authors experienced, DAS (Daewoo Shipbuilding Scheduling System) has adopted a two-layered hierarchical architecture. In the hierarchical architecture, individual scheduling systems composed of a high-level dock scheduler, DAS-ERECT and low-level assembly plant schedulers, DAS-PBS, DAS-3DS, DAS-NPS, and DAS-A7 try to search the best schedules under their own constraints. Moreover, the steep growth of communication technology and logistics enables it to introduce distributed multi-nation production plants by which different parts are produced by designated plants. Therefore vertical and lateral coordination among decomposed scheduling systems is necessary. No standard coordination mechanism of multiple scheduling systems exists, even though there are various scheduling systems existing in the area of scheduling research. Previous research regarding the coordination mechanism has mainly focused on external conversation without capacity model. Prior research has heavily focuses on agent-based coordination in the area of agent research. Yet, no scheduling domain has been developed. Previous research regarding the agent-based scheduling has paid its ample attention to internal coordination of scheduling process, a process that has not been efficient. In this study, we suggest a general framework for agent-based coordination of multiple scheduling systems in global supply chain. The purpose of this study was to design a standard coordination mechanism. To do so, we first define an individual scheduling agent responsible for their own plants and a meta-level coordination agent involved with each individual scheduling agent. We then suggest variables and values describing the individual scheduling agent and meta-level coordination agent. These variables and values are represented by Backus-Naur Form. Second, we suggest scheduling agent communication protocols for each scheduling agent topology classified into the system architectures, existence or nonexistence of coordinator, and directions of coordination. If there was a coordinating agent, an individual scheduling agent could communicate with another individual agent indirectly through the coordinator. On the other hand, if there was not any coordinating agent existing, an individual scheduling agent should communicate with another individual agent directly. To apply agent communication language specifically to the scheduling coordination domain, we had to additionally define an inner language, a language that suitably expresses scheduling coordination. A scheduling agent communication language is devised for the communication among agents independent of domain. We adopt three message layers which are ACL layer, scheduling coordination layer, and industry-specific layer. The ACL layer is a domain independent outer language layer. The scheduling coordination layer has terms necessary for scheduling coordination. The industry-specific layer expresses the industry specification. Third, in order to improve the efficiency of communication among scheduling agents and avoid possible infinite loops, we suggest a look-ahead load balancing model which supports to monitor participating agents and to analyze the status of the agents. To build the look-ahead load balancing model, the status of participating agents should be monitored. Most of all, the amount of sharing information should be considered. If complete information is collected, updating and maintenance cost of sharing information will be increasing although the frequency of communication will be decreasing. Therefore the level of detail and updating period of sharing information should be decided contingently. By means of this standard coordination mechanism, we can easily model coordination processes of multiple scheduling systems into supply chain. Finally, we apply this mechanism to shipbuilding domain and develop a prototype system which consists of a dock-scheduling agent, four assembly- plant-scheduling agents, and a meta-level coordination agent. A series of experiments using the real world data are used to empirically examine this mechanism. The results of this study show that the effect of agent-based platform on coordinated scheduling is evident in terms of the number of tardy jobs, tardiness, and makespan.

• The Journal of the Korea Contents Association
• /
• v.18 no.5
• /
• pp.191-214
• /
• 2018

This research empirically analyzed the selection factors and the locational selection factors of the medical service facilities according to the gradual increase of the importance of the selection factors and the locational selection factors regarding the establishments of the small- and medium-sized hospitals according to the rapid changes of the socio-economic conditions. By analyzing the priority order according to the levels of the importance of each evaluation item factor through a research related to the selection factors and the locational selection factors of the small- and medium-sized hospitals and by drawing what the important factors that have the influences on the competitiveness of the pre-existent small- and medium-sized hospitals are through the classification of the real estate locational factors and the non-locational factors, the purpose lies in utilizing them as the basic data and materials for the opening strategies of the small- and medium-sized hospitals considering the special, locational characteristics according to the important factors of the selection factors of the small- and medium-sized hospitals, regarding the medical suppliers that have been preparing, for opening the new, small- and medium-sized hospitals. Based on the results of the preceding researches and the researches on the case examples, 28 evaluation factors were arrived at in terms of the level of the medical treatment, the medical services, the accessibilities of the hospitals, the conveniences of the hospitals, and the physical environment. And, regarding the 28 detailed evaluation factors that had been collected, through the interviews with the related experts, the 5 factors of the medical level, the medical service, the expertise of the hospital, the convenience of the hospital, and the physical environment were selected as the upper class evaluation factors. And, according to each upper class, a total of 28 low-part evaluation factors were selected. Regarding the optimal evaluation factors that were selected, the optimal locational factors were selected by carrying out an AHP questionnaire survey investigation with 200 medical experts as the subjects. Regarding the AHP analysis results, similarly with the case examples of the precedent researches, the levels of the importance appeared in the order of the medical level, the medical services, the accessibility of the hospital, the physical environment, and the convenience. And the factors that were related to the facilities of a hospital appeared low. The results of this research can be applied in providing the basis for the decision-makings regarding the selections of the locations of the small- and medium-sized hospitals in the future.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.869-877
• /
• 2008

The purpose of this study is to investigate the trends and patterns of variou kind of water uses in a household by metering in Korea. Water use components are classified by toilet, washbowl, bathing, laundry, kitchen, etc. Flow meters are installed in 146 household selected by sampling in all around Korea. The data are gathered by web-based data collection system from the year 2002 to 2006, considering pre-investigated data such as occupation, revenue, family members, housing types, age, floor area, water saving devices, education, etc. Reliable data are selected by upper fence method for each observed water use component and statistical characteristics are estimated for each residential type to determine liter per capita per day. Estimated domestic per capita day show an indoor water use with the range from $150{\ell}pcd$ to $169{\ell}pcd$ for each housing type as the order of high rise apartment, multi-house, and single house. As the order of consuming amount among water use components, it is investigated that toilet($38.5{\ell}pcd$) is the first, and the second is laundry water($30.8{\ell}pcd$), the third is kitchen($28.4{\ell}pcd$), the fourth is bathtub($24.7{\ell}pcd$), the next is washbowl($15.4{\ell}pcd$). The results are compared with water uses in U.K. and U.S. As life style has been changed into western style, pattern of water use in Korea is tend to be similar with the U.S. water use pattern. Compared with the surveying results by Bradley, on 1985. Thirty liter of total use increased with the advancement of economic level, and a little change of water use pattern can be found. Especially, toilet water take almost half part of total water use and laundry water shows lowest as 11% in surveying at the year of 1985. But, this study shows that 39 liter, 28% of toilet water, has been decreased by the spread of saving devices and campaign. It is supposed that the spread large sized laundry machine make by-hand laundry has been decreased and water use increased. Unit water amount of each end-use in household can be applied to design factor for water and wastewater facilities, and it play a role as information in establishing water demand forecasting and conservation policy.

• Radiation Oncology Journal
• /
• v.17 no.1
• /
• pp.1-8
• /
• 1999

Purpose : Experimental studies have implicated the wild type p53 In cellular response to radiation. Whether altered p53 function can lead to changes in clinical radiocurability remains an area of ongoing study. This study was performed to investigate whether any correlation between change of p53 and outcome of curative radiation therapy in patients with head and neck cancels. Methods : Immunohistochemical analysis with a mouse monoclonal antibody (DO-7) specific for human p53 was used to detect to overexpression of protein in formalin fixed, paraffin-embedded tumor sample from 55 head and neck cancer patients treated with curative radiation therapy (median dose of 7020 cGy) from February 1988 to March 1996 at 51. Mary's Hospital. Overexpression of p53 was correlated with locoregional control and survival using Kaplan-Meier method. A Cox regression multi-variate analysis was peformed that included all clinical variables and status of p53 expression. Results : Thirty-seven (67.2$\%$) patients showed overexpression of p53 by immunohistochemical staining in their tumor. One hundred percent of oral cavity, 70$\%$ of laryngeal, 66.7$\%$ of oropharyngeal, 66.7$\%$ of hypopharyngeal cancer showed p53 overexpression (P=0.05). The status of p53 had significant relationship with stage of disease (P=0.03) and history of smoking (P=0.001). The overexpression of p53 was not predictive of response rate to radiation therapy. The locoregional control was not significantly affected by p53 status. Overexpression of p53 didn't have any prognostic implication for disease free survival and overall survival. Primary site and stage of disease were significant prognostic factors for survival. Conclusions : The p53 overexpression as detected by immunohistochemical staining had significant correlation with stage, primary site of disease and smoking habit of patients. The p53 overexpression didn't have any predictive value for outcome of curative radiation therapy in a group of head and neck cancers.

• Korean Business Review
• /
• v.19 no.1
• /
• pp.53-80
• /
• 2006

This research has been accomplished to build up the growth strategies of Kangwon district's small & medium-sized construction firms. For this purpose, we made an investigation of the present situation and status for existing regional small & medium construction firms by analyzing data. Based on the results from this study, the following growth strategies are suggested to gain their competitive advantages. Firstly, most of all, the role of the top manager is the most important factor since most of the top manager for the small & medium-sized construction firms coincide with the owner the firms. Secondly, the specialization strategy is to establish. Above all they concentrate their business capacities on core business. Then, this growth strategy should be based on the selective escalation of functions in order to maintain an appropriate level of construction works. Thirdly, the specialized skills and skilled workers are ensured for competitive advantages. For human resource development, they should train workers to be multi-functioned on the assumption the they could stay at firm until they wish to retire. Finally, the government must also spare no effort to encourage the small & medium-sized construction firms to build up it's competitive power and cultivate it's spontaneous generation power though the reformation of system related whit the small and medium construction industry.

• Journal of The Korean Association For Science Education
• /
• v.37 no.3
• /
• pp.507-521
• /
• 2017

The purpose of this study is to investigate a meaningful path model among the components of students' positive experiences about science and science learning to understand the interactive relationships among different variables of affective domains. Positive Experiences about Science (PES) means whole experiences that have positive effects on students' affectional achievement related with science learning, which consists of science academic emotion, science-related self-concept, science learning motivation, science-related attitude, and science-related career aspiration. We conducted an online survey with 1,841 students consisting of 4th, 6th, 8th, and 10th graders from 17 provinces and cities using Test for Indicators of Positive Experiences about Science (TIPES). To explore the structural relationships among variables, we selected and analyzed an optimal structural equation model and then conducted multigroup analyses among groups. According to the analysis of the structural equation model, 'positive as well as negative science academic emotion' has effects on science learning motivation, science-related attitude, and science-related career aspiration via science-related self-concept. According to the independent t-test results for TIPES scores by participants' characteristics, there were statistically significant differences in the average scores of five sub-components of PES depending on gender, school-level, school location, and participation in science-related activities. According to the multi-group analysis results, the difference of path coefficients by gender and school-level were statistically significant, whereas the difference of path coefficients by school location and participation were not significant. Discussed in the conclusion are the implications of this research for science education research and ways to help students' affectional achievement related with science learning.

• Journal of Gastric Cancer
• /
• v.9 no.4
• /
• pp.186-192
• /
• 2009

Purpose: The aim of this study was to analyze the trend of the literature reported in the Journal of Korean Gastric Cancer Association (JKGCA) and the Journal of Korean Surgical Society (JKSS) in order to suggest new directions for the future studies on gastric cancer. Materials and Methods: The papers published in the Journal of Korean Gastric Cancer Association (JKGCA) and the Journal of Korean Surgical Society (JKSS) between 2001 and 2008 were compared and summarized in terms of the following categories, retrospective study, prospective study, case report, biomolecular study, genetic study, tumor marker study, review article, and report. Results: For recent 8 years, while the number of review articles in JKSS had initially increased, gradually fallen down and recently increased again, only a few (only 6 publications) in JKGCA have been published. The number of case reports in JKSS has gradually increased and fallen down. On the other hand, a few of case reports (1~3 publications) has been annually published in JKSS. Uniquely, reports were published only in JKGCA with the noticeable increase during the period from 2004 to 2005. For retrospective studies, in JKGCA the number started off very high and decreased, and finally increased again (U-shaped), whereas it had a bell-shaped trend in JKSS. The number of prospective studies in JKGCA had a bell-shaped trend, but the one in JKSS continued to decrease. Few papers of molecular biologic study, tumor marker study and genetic study had been published in both journals. Conclusion: We concluded that the transition from retrospective studies to prospective studies as well as a comprehensive multi-disciplinary team management of a clinical research would represent a desirable strategy in gastric cancer research.

• Journal of Gastric Cancer
• /
• v.13 no.3
• /
• pp.164-171
• /
• 2013

Purpose: Laparoscopy-assisted distal gastrectomy for early gastric cancer has gained acceptance and popularity worldwide. However, laparoscopy-assisted distal gastrectomy for advanced gastric cancer is still controversial. Therefore, we propose this prospective randomized controlled multi-center trial in order to evaluate the safety and feasibility of laparoscopy assisted D2-gastrectomy for advanced stage gastric cancer. Materials and Methods: Patients undergoing distal gastrectomy for advanced gastric cancer staged cT2/3/4 cN0/1/2/3a cM0 by endoscopy and computed tomography are eligible for enrollment after giving their informed consent. Patients will be randomized either to laparoscopyassisted distal gastrectomy or open distal gastrectomy. Sample size calculation revealed that 102 patients are to be included per treatment arm. The primary endpoint is the non-compliance rate of D2 dissection; relevant secondary endpoints are three-year disease free survival, surgical and postoperative complications, hospital stay and unanimity rate of D2 dissection evaluated by reviewing the intraoperative video documentation. Discussion: Oncologic safety is the major concern regarding laparoscopy-assisted distal gastrectomy for advanced gastric cancer. Therefore, the non-compliance rate of clearing the N2 area was chosen as the most important parameter for the technical feasibility of the laparoscopic procedure. Furthermore, surgical quality will be carefully reviewed, that is, three independent experts will review the video records and score with a check list. For a long-term result, disease free survival is considered a secondary endpoint for this trial. This study will offer promising evidence of the feasibility and safety of Laparoscopy-assisted distal gastrectomy for advanced gastric cancer. Trial Registration: NCT01088204 (international), NCCCTS-09-448 (Korea).

• KDI Journal of Economic Policy
• /
• v.31 no.2
• /
• pp.127-153
• /
• 2009

There is a growing concern about potential harmful effect of second-hand or environmental tobacco smoking. As a result, smoking bans in workplace become more prevalent worldwide. In Korea, workplace smoking ban policy become more restrictive in 2003 when National health enhancing law was amended. The new law requires all office buildings larger than 3,000 square meters (multi-purpose buildings larger than 2,000 square meters) should be smoke free. Therefore, a lot of indoor office became non smoking area. Previous studies in other counties often found contradicting answers for the effects of workplace smoking ban on smoking behavior. In addition, there was no study in Korea yet that examines the causal impacts of smoking ban on smoking behavior. The situation in Korea might be different from other countries. Using 2001 and 2005 Korea National Health and Nutrition surveys which are representative for population in Korea we try to examine the impacts of law change on current smoker and cigarettes smoked per day. The amended law impacted the whole country at the same time and there was a declining trend in smoking rate even before the legislation update. So, the challenge here is to tease out the true impact only. We compare indoor working occupations which are constrained by the law change with outdoor working occupations which are less impacted. Since the data has been collected before (2001) and after (2005) the law change for treated (indoor working occupations) and control (outdoor working occupations) groups we will use difference in difference method. We restrict our sample to working age (between 20 and 65) since these are the relevant population by the workplace smoking ban policy. We also restrict the sample to indoor occupations (executive or administrative and administrative support) and outdoor occupations (sales and low skilled worker) after dropping unemployed and someone working for military since it is not clear whether these occupations are treated group or control group. This classification was supported when we examined the answers for workplace smoking ban policy existing only in 2005 survey. Sixty eight percent of indoor occupations reported having an office smoking ban policy compared to forty percent of outdoor occupation answering workplace smoking ban policy. The estimated impacts on current smoker are 4.1 percentage point decline and cigarettes per day show statistically significant decline of 2.5 cigarettes per day. Taking into account consumption of average sixteen cigarettes per day among smokers it is sixteen percent decline in smoking rate which is substantial. We tested robustness using the same sample across two surveys and also using tobit model. Our results are robust against both concerns. It is possible that our measure of treated and control group have measurement error which will lead to attenuation bias. However, we are finding statistically significant impacts which might be a lower bound of the true estimates. The magnitude of our finding is not much different from previous finding of significant impacts. For cigarettes per day previous estimates varied from 1.37 to 3.9 and for current smoker it showed between 1%p and 7.8%p.

• International Commerce and Information Review
• /
• v.4 no.2
• /
• pp.253-277
• /
• 2002

Nowaday, the advanced technology in information and communication has been leading the dramatic change of transaction paradigm expansion from physical basis to electronic one. As we know, financial services support most of financial exchange between two business parties. So the expansion of electronic transaction paradigm affects to every financial institutions which provide financial services. Thus, financial institutions have accepted e-Finance systems and providing internet financial services to live in the competition. The purpose of this study is to contribute the qualitative enhancement of its customer service, rapid diffusion and accurate strategy establishment for e-Finance industry in the user side. Through the literature review and factor and reliability analysis, this study selects six diffusion factors such as efficiency of perceived e-Finance, reliability and safety of e-Finance in perceived e-Finance itself's characteristic; confidence, technical factors and the customer service quality of e-Finance system in perception on e-Finance System; inclination to innovation in the personal characteristic. According to result of hypothesis verification by using logistics regression analysis, technical factors and the customer service quality of e-Finance system in perception on e-Finance System and inclination to innovation in the personal characteristic gave statistically positive effect to the diffusion decision at the significant level 0.05 and 0.01. However efficiency of perceived e-Finance, reliability and safety of e-Finance in perceived e-Finance itself's characteristic didn't affect to diffusion decision and confidence of e-Finance system in perception on e-Finance System didn't have any statistical significancy. This study can be used as a basic material for the forward empirical study of diffusion factors in the user side and be able to apply to company and government policy making or embodiment, determination for customer service quality degree of financial institutions. But this study has some limitations like didn't touch satisfaction factors and its effect, only deal domestic customers and didn't use multi-regression analysis.