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Dinosaur Track-Bearing Deposits at Petroglyphs of Bangudae Terrace in Daegokcheon Stream, Ulju (National Treasure No. 285): Occurrences, Paleoenvironments, and Significance in Natural history (국보 제285호 울주 대곡리 반구대 암각화 지역의 공룡발자국 화석층 : 산상, 고환경 및 자연사적 가치)

  • Kim, Hyun Joo;Paik, In Sung;Lim, Jong-Deock
    • Korean Journal of Heritage: History & Science
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    • v.47 no.2
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    • pp.46-67
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    • 2014
  • The Dinosaur track-bearing deposits recently found at Bangudae Petroglyph site in Ulju (National Treasure No. 285) have been studied in the aspects of sedimentology, paleoenvironments, and significance in natural history. The dinosaur tracks occur in the Daegu Formation (late Early Cretaceous), and over 80 footprints including 43 ornithopod footprints, 36 sauropod footprints, and 2 theropod footprints are preserved in this tracksite. The track-bearing deposits consist of irregularly interlaminated siltstone and mudstone, calcareous sandy to silty mudstone, thin-bedded tuffaceous sandstone, planar- to cross-laminated sandstone, and thin- to medium-bedded graded sandstone, and they are interpreted to be sheetflood deposits on an alluvial plain. Diverse types of ripples and mudcracks, rainprints, and invertebrate trace fossils are observed in these deposits, and the crest-lines of wave ripples do not show preferred orientation. Dinosaur footprints occur as true prints, underprints, overtracks, and casts on the bedding surfaces, and the orientation of trackways are scattered. It is interpreted that paleoclimatic condition of the track-bearing deposits were semiarid with alternation of wetting and drying periods, and that dinosaurs frequented small and shallow ponds during wetting periods and recorded their tracks on an alluvial plain. The frequent occurrence of dinosaur tracks in study area indicates that the Cretaceous deposits around Daegokcheon Stream are very useful sedimentological and paleontological records to understand the paleoecology and paleoenvironments during the dinosaur age in Korean Peninsula. Consequently the dinosaur track-bearing deposits around Daegokcheon Stream should be further studied in sedimentary geology and paleontology in order to enhance cultural heritage value of the Petroglyphs of Bangudae Terrace as the World Heritage.

Issues Involving the Relationship between Religion and the Anti-Japanese Independence Movement: A Case Study of Mugeukdo (종교와 항일독립운동, 그리고 쟁점 - 무극도 사례를 중심으로 -)

  • Ko, Byoung-chul
    • Journal of the Daesoon Academy of Sciences
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    • v.35
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    • pp.39-71
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    • 2020
  • Ever since gaining liberation in 1945, Korean society has constantly recalled memories of Japan's invasion and Korea's anti-Japanese movements for an independent state (AMIS). In the process, a small number of new religious groups were also identified as main subjects within AMIS. However, the logic necessary to connect these religious groups with AMIS was still weak. In order to solve this situation academically, the purpose of this article is to illuminate the activities of Mugeukdo (無極道) and Jo Jeongsan (趙鼎山) through the lens of AMIS and to reflect on the issues that will arise when linking the religion with AMIS. Regarding this purpose, this article analyzed the internal and external data collected by Daesoon Jinrihoe (大巡眞理會) about Jo Jeongsan and Mugeukdo's activities linked to AMIS. Later, this paper presents several tasks for future research on this subject matter. Specifically, according to Chapter II, the AMIS of Jo Jeongsan and Mugeukdo were generally centered on resistance at the family level, Jo Jeongsan's order to participate in the March 1st Movement, and Mugeukdo's industrial activities. In Chapter III, I reviewed the contents of Chapter II using Daesoon Jinrihoe's external materials. According to the results of the review, future research is required to discover and cross-check materials related to the AMIS of Jo Jeongsan and Mugeukdo believers. Likewise, further research is needed to highlight the theory of the enthronement of emperor (天子登極說) and the Great Opening of the later world (後天開闢) in terms of AMIS. These efforts can make contributions that increase the credibility of Daesoon Jinrihoe's internal data on the AMIS of Jo Jeongsan and Mugeukdo and expand the periphery of AMIS as it relates to certain religious groups. Subsequently, in Chapter IV, I present three items for reflecting upon the connection between certain religious groups and AMIS. The first is that criteria for establishing the category of AMIS is necessary to determine whether religious activities can be included. Second, reductionist approaches make it difficult to explain the reasons why some of the people who participated in AMIS did so while forming 'new religious movements,' and why these groups have maintained their religious identity even after liberation was achieved in 1945. Third, it is necessary to distinguish between the primary and the secondary dimensions to elaborate on the connection between these religions and AMIS. This means that researchers should be expected to look at whether the activities in question are based on a religious worldview and whether the goal of the activities is the realization of AMIS or the implementation of some aspect of that religious worldview. In the future, considering the mechanisms that make AMIS memorable in Korea, religious groups and religious studies should take greater interest in discovering and accumulating data that facilitates research on these topics. At the same time, effort should be made to find the basis for AMIS within religious worldviews. It can also be made possible through specific interest in further elaboration on the various AMIS-related activities of Jo Jeongsan and Mugeukdo.

The Effects of Technological Competitiveness by Country on The Increase of Unicorn Companies (국가별 기술경쟁력이 유니콘기업 증가에 미치는 영향에 관한 연구)

  • Kyu Hoon Cho;Dong Woo Yang
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.19 no.1
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    • pp.55-73
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    • 2024
  • Unicorn companies are attracting attention around the world as they are recognized for their high corporate value in a short period of time as an innovative business models. Their growth process presents good lessons for the startup ecosystem and have a positive impact on national economic development and job creation. However, previous studies related to unicorn companies are focused on 'event studies' and 'case studies' such as characteristics of founders, environmental factors, business models and success/failure cases of companies already recognized as unicorns rather than a multifaceted approach. The occurrence of unicorn companies and Macroscopic analysis of related factors is lacking. Against this background, this study are considering the characteristics of unicorns examined through previous research and the current status unicorns with a high proportion of technology companies, the purpose was to analyze the impact of the country's technological competitiveness, such as 'technology human resource index', 'R&D index', and 'technology infrastructure index', on the increase in unicorn companies. For statistical analysis, data published by various international organizations, the Bank of Korea, and Statistics Korea from 2017 to 2020 and unicorn company data compiled by CB Insights were used as panel data for 44 countries to be tested by multiple regression analysis. As a result of the study, it was confirmed that the number of science majors had a positive (+) effect on the increase of unicorn companies in the case of technology human resource index, and in the case of R&D index, the total amount of R&D investment had a positive (+) effect on the increase of unicorn companies, while the number of Triad Patents Families and the number of scientific and technological papers published had a negative (-) effect on the increase of unicorn companies. Finally, in the case of technology infrastructure index, it was confirmed that the number of the world's 500th-ranked universities had a positive (+) effect on the increase of unicorn companies. This study is the first to reveal the causal relationship between national technological competitiveness and unicorn company growth based on country-specific and time-series empirical data, which were insufficiently covered in previous studies. and compared to the UN's ranking of the global industrial competitiveness index and the OECD's total R&D investment by country, Korea is considered to have technological and growth potential, while the number of unicorn companies driving growth as leaders of the innovative economy is relatively small, so the research results can be used when establishing policies to discover and foster unicorn companies in the future.

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Factors Affecting International Transfer Pricing of Multinational Enterprises in Korea (외국인투자기업의 국제이전가격 결정에 영향을 미치는 환경 및 기업요인)

  • Jun, Tae-Young;Byun, Yong-Hwan
    • Korean small business review
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    • v.31 no.2
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    • pp.85-102
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    • 2009
  • With the continued globalization of world markets, transfer pricing has become one of the dominant sources of controversy in international taxation. Transfer pricing is the process by which a multinational corporation calculates a price for goods and services that are transferred to affiliated entities. Consider a Korean electronic enterprise that buys supplies from its own subsidiary located in China. How much the Korean parent company pays its subsidiary will determine how much profit the Chinese unit reports in local taxes. If the parent company pays above normal market prices, it may appear to have a poor profit, even if the group as a whole shows a respectable profit margin. In this way, transfer prices impact the taxable income reported in each country in which the multinational enterprise operates. It's importance lies in that around 60% of international trade involves transactions between two related parts of multinationals, according to the OECD. Multinational enterprises (hereafter MEs) exert much effort into utilizing organizational advantages to make global investments. MEs wish to minimize their tax burden. So MEs spend a fortune on economists and accountants to justify transfer prices that suit their tax needs. On the contrary, local governments are not prepared to cope with MEs' powerful financial instruments. Tax authorities in each country wish to ensure that the tax base of any ME is divided fairly. Thus, both tax authorities and MEs have a vested interest in the way in which a transfer price is determined, and this is why MEs' international transfer prices are at the center of disputes concerned with taxation. Transfer pricing issues and practices are sometimes difficult to control for regulators because the tax administration does not have enough staffs with the knowledge and resources necessary to understand them. The authors examine transfer pricing practices to provide relevant resources useful in designing tax incentives and regulation schemes for policy makers. This study focuses on identifying the relevant business and environmental factors that could influence the international transfer pricing of MEs. In this perspective, we empirically investigate how the management perception of related variables influences their choice of international transfer pricing methods. We believe that this research is particularly useful in the design of tax policy. Because it can concentrate on a few selected factors in consideration of the limited budget of the tax administration with assistance of this research. Data is composed of questionnaire responses from foreign firms in Korea with investment balances exceeding one million dollars in the end of 2004. We mailed questionnaires to 861 managers in charge of the accounting departments of each company, resulting in 121 valid responses. Seventy six percent of the sample firms are classified as small and medium sized enterprises with assets below 100 billion Korean won. Reviewing transfer pricing methods, cost-based transfer pricing is most popular showing that 60 firms have adopted it. The market-based method is used by 31 firms, and 13 firms have reported the resale-pricing method. Regarding the nationalities of foreign investors, the Japanese and the Americans constitute most of the sample. Logistic regressions have been performed for statistical analysis. The dependent variable is binary in that whether the method of international transfer pricing is a market-based method or a cost-based method. This type of binary classification is founded on the belief that the market-based method is evaluated as the relatively objective way of pricing compared with the cost-based methods. Cost-based pricing is assumed to give mangers flexibility in transfer pricing decisions. Therefore, local regulatory agencies are thought to prefer market-based pricing over cost-based pricing. Independent variables are composed of eight factors such as corporate tax rate, tariffs, relations with local tax authorities, tax audit, equity ratios of local investors, volume of internal trade, sales volume, and product life cycle. The first four variables are included in the model because taxation lies in the center of transfer pricing disputes. So identifying the impact of these variables in Korean business environments is much needed. Equity ratio is included to represent the interest of local partners. Volume of internal trade was sometimes employed in previous research to check the pricing behavior of managers, so we have followed these footsteps in this paper. Product life cycle is used as a surrogate of competition in local markets. Control variables are firm size and nationality of foreign investors. Firm size is controlled using dummy variables in that whether or not the specific firm is small and medium sized. This is because some researchers report that big firms show different behaviors compared with small and medium sized firms in transfer pricing. The other control variable is also expressed in dummy variable showing if the entrepreneur is the American or not. That's because some prior studies conclude that the American management style is different in that they limit branch manger's freedom of decision. Reviewing the statistical results, we have found that managers prefer the cost-based method over the market-based method as the importance of corporate taxes and tariffs increase. This result means that managers need flexibility to lessen the tax burden when they feel taxes are important. They also prefer the cost-based method as the product life cycle matures, which means that they support subsidiaries in local market competition using cost-based transfer pricing. On the contrary, as the relationship with local tax authorities becomes more important, managers prefer the market-based method. That is because market-based pricing is a better way to maintain good relations with the tax officials. Other variables like tax audit, volume of internal transactions, sales volume, and local equity ratio have shown only insignificant influence. Additionally, we have replaced two tax variables(corporate taxes and tariffs) with the data showing top marginal tax rate and mean tariff rates of each country, and have performed another regression to find if we could get different results compared with the former one. As a consequence, we have found something different on the part of mean tariffs, that shows only an insignificant influence on the dependent variable. We guess that each company in the sample pays tariffs with a specific rate applied only for one's own company, which could be located far from mean tariff rates. Therefore we have concluded we need a more detailed data that shows the tariffs of each company if we want to check the role of this variable. Considering that the present paper has heavily relied on questionnaires, an effort to build a reliable data base is needed for enhancing the research reliability.

The Yellow Sea Ecoregion Conservation Project : the Present Situation and its Implications (황해생태지역 보전사업 추진현황 및 시사점)

  • Kim, Gwang Tae;Choi, Young Rae;Jang, Ji Young;Kim, Woong-Seo
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.15 no.4
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    • pp.337-348
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    • 2012
  • The Yellow Sea Ecoregion Conservation Project is a joint international project which is carried out under the purposes of conserving the habitats in the Yellow Sea Ecoregion and biodiversity from various threats that damage ecosystems, informing the importance and value of the Yellow Sea Ecoregion, and promoting the understanding and interests of Korea, China and Japan. Subsequent to the Yellow Sea Ecoregion Planning Programme which had been performed during the period from 2002 to 2006, the Yellow Sea Ecoregion Support Project has been performed over 7 years in total from 2007 to 2014. Panasonic is sponsoring the financing of the project, and the organizations in charge of the project by country are Korea Institute of Ocean Science & Technology for Korea and World Wide Fund for Nature branches for China and Japan. While the Yellow Sea Ecoregion Planning Programme was focused on the biological assessment and the selection of potential priority area by scientific review, the Yellow Sea Ecoregion Support Project is oriented toward practical activities targeting more diversified stakeholder. Especially, this project plans to support direct conservation activities in the region and participation and cooperation from local residents. The project plan is comprised of 3 phases. During the first period from 2008 to 2009, small grant projects were operated targeting 16 institutions of Korea and China, and for the second period from 2010 to 2012, one place each was selected as demonstration site for habitat conservation in Korea and China respectively and supported for three years to introduce the conservation method based on international standards such as the management of marine protected areas, ecosystem-based management and community-based management and simultaneously to develop habitat conservation activities suitable for national and regional characteristics. During the period from 2013 to 2014 which is the last phase, the project plans to distribute the performance of small grant projects and demonstration site activities through a series of forums among stakeholder. Through the activities described above, the recognition of general public on the conservation of the Yellow Sea Ecoregion was changed positively, and community-based management began to be reflected in the policies for the marine protected areas of central and local government.

Some lessons from German startup policies (독일의 창업정책과 정책적 시사점)

  • Kim, Young-woo
    • Journal of Venture Innovation
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    • v.1 no.1
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    • pp.49-65
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    • 2018
  • For a long time the German economy was primarily defined by large corporations and thriving small and medium-sized enterprises. Since about 2005 a second strand has started to emerge and it is one which is becoming increasingly important and is creating jobs - start-ups in the digital sector. This start-up activity is taking an important role in Germany's economic development: Start-up companies spawn innovations and create jobs, thus promoting the concept of competition. In general "start-up" refers to digitally-driven companies that are not more than five years old. Germany's start-up policy consists of three main parts. First of all, Germany has the characteristics of technology-based start-ups. The Hartz reform since 2002 has shown its focus on technology-based start-ups. In particular, it is the most appropriate for a start-up company to take the role of a new technology company to respond to changes in the global industrial structure. Second, it is approaching from a long-term perspective. In this regard, the small business policy, including Germany's new business policy, is seen as a tradition that can be consistent and can make policy decisions based on the basics rather than following the times. Third, the government is implementing policies centered on demand. Germany's start-up policy is summarized as a technology-based policy and new job creation. The policy response is that the government seeks the best combination of policies by adapting them to the times from the broad trend of employment market policies. What is important here is that policies are made based on consumers, not suppliers, in the process of policy making and implementation. With the Digital Agenda 2020 the Federal government has likewise committed itself to preparing the digital economy for international competition and making Germany the "No. 1 digital growth country in Europe". Ever since 1998 the Federal Ministry for Economic Affairs and Energy (BMWi) has awarded the "EXIST" start-up scholarship to students and graduates. The Ministry also invests in the High Tech start-up fund. Together with Kreditanstalt für Wiederaufbau (KfW) and 18 other investors from the world of business the seed investor promotes young technology companies. Germany offers start-ups a good infrastructure and lots of funding opportunities. Berlin is regarded as Europe's start-up capital and also attracts lots of international young entrepreneurs.

Recommender Systems using Structural Hole and Collaborative Filtering (구조적 공백과 협업필터링을 이용한 추천시스템)

  • Kim, Mingun;Kim, Kyoung-Jae
    • Journal of Intelligence and Information Systems
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    • v.20 no.4
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    • pp.107-120
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    • 2014
  • This study proposes a novel recommender system using the structural hole analysis to reflect qualitative and emotional information in recommendation process. Although collaborative filtering (CF) is known as the most popular recommendation algorithm, it has some limitations including scalability and sparsity problems. The scalability problem arises when the volume of users and items become quite large. It means that CF cannot scale up due to large computation time for finding neighbors from the user-item matrix as the number of users and items increases in real-world e-commerce sites. Sparsity is a common problem of most recommender systems due to the fact that users generally evaluate only a small portion of the whole items. In addition, the cold-start problem is the special case of the sparsity problem when users or items newly added to the system with no ratings at all. When the user's preference evaluation data is sparse, two users or items are unlikely to have common ratings, and finally, CF will predict ratings using a very limited number of similar users. Moreover, it may produces biased recommendations because similarity weights may be estimated using only a small portion of rating data. In this study, we suggest a novel limitation of the conventional CF. The limitation is that CF does not consider qualitative and emotional information about users in the recommendation process because it only utilizes user's preference scores of the user-item matrix. To address this novel limitation, this study proposes cluster-indexing CF model with the structural hole analysis for recommendations. In general, the structural hole means a location which connects two separate actors without any redundant connections in the network. The actor who occupies the structural hole can easily access to non-redundant, various and fresh information. Therefore, the actor who occupies the structural hole may be a important person in the focal network and he or she may be the representative person in the focal subgroup in the network. Thus, his or her characteristics may represent the general characteristics of the users in the focal subgroup. In this sense, we can distinguish friends and strangers of the focal user utilizing the structural hole analysis. This study uses the structural hole analysis to select structural holes in subgroups as an initial seeds for a cluster analysis. First, we gather data about users' preference ratings for items and their social network information. For gathering research data, we develop a data collection system. Then, we perform structural hole analysis and find structural holes of social network. Next, we use these structural holes as cluster centroids for the clustering algorithm. Finally, this study makes recommendations using CF within user's cluster, and compare the recommendation performances of comparative models. For implementing experiments of the proposed model, we composite the experimental results from two experiments. The first experiment is the structural hole analysis. For the first one, this study employs a software package for the analysis of social network data - UCINET version 6. The second one is for performing modified clustering, and CF using the result of the cluster analysis. We develop an experimental system using VBA (Visual Basic for Application) of Microsoft Excel 2007 for the second one. This study designs to analyzing clustering based on a novel similarity measure - Pearson correlation between user preference rating vectors for the modified clustering experiment. In addition, this study uses 'all-but-one' approach for the CF experiment. In order to validate the effectiveness of our proposed model, we apply three comparative types of CF models to the same dataset. The experimental results show that the proposed model outperforms the other comparative models. In especial, the proposed model significantly performs better than two comparative modes with the cluster analysis from the statistical significance test. However, the difference between the proposed model and the naive model does not have statistical significance.

Development of Agent-based Platform for Coordinated Scheduling in Global Supply Chain (글로벌 공급사슬에서 경쟁협력 스케줄링을 위한 에이전트 기반 플랫폼 구축)

  • Lee, Jung-Seung;Choi, Seong-Woo
    • Journal of Intelligence and Information Systems
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    • v.17 no.4
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    • pp.213-226
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    • 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.

High Resolution MR Images from 3T Active-Shield Whole-Body MRI System (3T 능동차페형 전신 자기공명영상 장비로부터 얻어진 고해상도 자기공명영상)

  • Bo-Young Choe;Sei-Kwon Kang;Myoung-Ja Chu;Hyun-Man Baik;Euy-Neyng Kim
    • Investigative Magnetic Resonance Imaging
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    • v.5 no.2
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    • pp.138-148
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    • 2001
  • Purpose : Within a clinically acceptable time frame, we obtained the high resolution MR images of the human brain, knee, foot and wrist from 3T whole-body MRI system which was equipped with the world first 37 active shield magnet. Materials and Methods : Spin echo (SE) and Fast Spin Echo (FSE) images were obtained from the human brain, knee, foot and wrist of normal subjects using a homemade birdcage and transverse electromagnetic (TEM) resonators operating in quadrature and tuned to 128 MHz. For acquisition of MR images of knee, foot and wrist, we employed a homemade saddle shaped RF coil. Topical common acquisition parameters were as follows: matrix=$512{\times}512$, field of view (FOV) =20 cm, slice thickness = 3 mm, number of excitations (NEX)=1. For T1-weighted MR images, we used TR = 500 ms, TE = 10 or 17.4 ms. For T2-weighted MR images, we used TR=4000 ms, TE = 108 ms. Results : Signal to noise ratio (SNR) of 3T system was measured 2.7 times greater than that of prevalent 1.5T system. MR images obtained from 3T system revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter. Conclusion The present results demonstrate that the MR images from 3T system could provide better diagnostic quali\ulcorner of resolution and sensitivity than those of 1.5T system. The elevated SNR observed in the 3T high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the microscopic structural level under in vivo conditions. These images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods.

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Effects of Amount and Type of Jeotgal, a Traditional Korean Salted and Fermented Seafood, on N-Nitrosodimethylamine Formation during Storage of Kimchi (김치 저장 중 N-Nitrosodimethylamine 생성에 젓갈의 함량과 종류의 영향)

  • Kang, Kyung Hun;Kim, Sung Hyun;Kim, Sang-Hyun;Kim, Jeong Gyun;Sung, Nak-Ju;Lee, Soo-Jung;Chung, Mi Ja
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.9
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    • pp.1302-1309
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    • 2016
  • N-Nitrosodimethylamine (NDMA) is formed through reactions between dimethylamine (DMA) and nitrite. Jeotgal, a traditional Korean salted and fermented seafood, contains a large amount of DMA and is an ingredient of kimchi condiment. This study investigated the effects of amount and type of Jeotgal on changes in NDMA and its precursor contents during storage of kimchi. NDMA was found in all 23 Jeotgal samples, and DMA in nine salted and fermented shrimp samples showed levels ranging from 16.5 to 58.9 mg/kg (average of 30.9 mg/kg). The seven salted and fermented anchovy juice samples showed DMA levels ranging from 21.7 to 44.4 mg/kg (average of 34.5 mg/kg). Kimchi was assigned to one of the following five groups: kimchi without salted and fermented anchovy juice and salted and fermented shrimp (control), kimchi with small amount of salted and fermented anchovy juice (AK1), kimchi with large amount of salted and fermented anchovy juice (AK2), kimchi with small amount of salted and fermented shrimp (SK1), and kimchi with large amount of salted and fermented shrimp (SK2). SK2 had higher DMA content than SK1 during storage while AK2 had higher DMA content than AK1 after storage for 10 days. Nitrite contents of AK1 and SK1 were higher than those of AK2 and SK2 after storage for 20 days. NDMA content was significantly higher in SK2 than in SK1 after storage for 0 and 10 days, and NDMA content in AK2 was significantly higher compared to that in AK1 after storage for 0 days. The DMA and NDMA contents decreased in all kimchi samples during storage. The effects of amount and type of Jeotgal on DMA and NDMA contents were reduced after storage for 20 days. The results suggest that the content and type of Jeotgal have significant effects on formation of NDMA in kimchi.