• Journal of Conservation Science
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• v.33 no.5
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• pp.331-344
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• 2017

In this study, glass beads from Osan Sucheong were classified according to color into 10 groups. Among these groups, reddish brown, bluish green, and purplish blue were identified as the main colors of glass beads based on their large quantities in Osan Sucheong. The glass beads of these main colors were then classified according to their chemical compositions and and looked at the changing process. Based on the results, reddish brown and bluish green glass beads can both be divided into five types, and purplish blue glass beads can be divided into four types. Furthermore, according to continuity of type, it was identified as the main attributes that the reddish brown beads belong to two types, whereas the bluish green and purplish blue each belong to one type. Based on a review of primary attributes, beads of these three colors were identified as soda glass and high-alumina glass. The results indicate that these beads came from a single, consistent route of origin into the region. However, it is possible that glass beads came through various routes into Osan Sucheong in the $4^{th}$ century, because many types of chemical compositions have been detected for beads from this time.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.426-439
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• 1999

본 논문에서는 웹(World Wide Web)에서 사용자가 손쉽고 편리하게 이용할 수 있는 멀티미디어 대중교통 안내시스템 개발 경험을 소개한다. 개발된 시스템은 클라이언트와 서버 시스템, 경로탐색 시스템, 교통정보 저장 시스템, 노선 및 정류장 관리 시스템으로 구성되어 있다. 클라이언트에서 작동되는 사용자 인터페이스는 직관적으로 이해가 쉽고, 사용이 편리하며 인터액티브한 멀티미디어 대중 교통안내 서비스를 제공한다. 서버 시스템은 교통정보 수집 시스템으로부터 입력되는 데이타와, 경로탐색 시스템, 교통정보 저장 시스템과 연동되어 클라이언트의 요구사항을 처리하고 그 결과를 사용자에게 돌려준다. 수정된 A* 알고리즘을 이용하는 경로탐색 시스템은 최적경로를 탐색하며, 교통정보 저장 시스템은 현재 교통상황, 정류장, 노선, 지도 등의 정보를 저장한다. 노선 및 정류장 관리시스템은 시스템 관리자가 노선 또는 정류장 관리를 서버 화면의 지도상에서 효율적으로 수행할 수 있는 도구이다. 본 논문에서 다루는 대중교통 안내시스템은 Java로 구현하였기 때문에 확장과 이식이 용이하며, 시스템 유지보수 비용이 적게 드는 장점을 가지고 있다. 그리고, 웹 브라우저가 동작되는 환경에서는 어디서나 쉽게 접근이 가능하며 향후 구축될 Intelligent Transportation Systems(ITS)의 한 모듈로써 바로 작동될 수 있을 뿐만 아니라, 현재 인터넷상에서 제공되는 다양한 서비스와도 연동이 가능하다.Abstract This paper introduces our experience for developing a public transportation guidance system, which facilitates the World-Wide Web(WWW) to provide users with easier access and use. The proposed system is composed of four subsystems: client/server system, path search system, traffic data storage system, and traffic raw-data management system. The user interface in clients utilizes Java to furnish users with multimedia data accessibility and interactivity. The server processes clients' requests based on the traffic data coming from remote sensing devices and interacts with the path search system and traffic data storage system to provide users with the results. The path search system, which uses a modified A* algorithm, produces optimal solutions based on dynamic traffic data. The traffic data storage system stores the current traffic information together with the geographical information about the b$us_way routes. The traffic raw-data management system is a graphical user interface which enables the system manager to handle the traffic information easily on the map in the terminal screen. The system has considerable benefits such as portability, scalability, and flexibility since it is implemented using Java. Also, it can be extended to an integrated Intelligent Transportation Systems(ITS) which includes a variety of information on the Internet as well as traffic information.n.

• Economic and Environmental Geology
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• v.11 no.3
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• pp.89-98
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• 1978

Mineralogy, beneficiation, and processes of titanium ores are reviewed from petrographic viewpoints. The most important titanium minerals are ilmenite ($FeTiO_3$) and rutile ($TiO_2$). Ilmenite will play major role :for raw material, because rutile are rapidly diminishing. Thus, there is a need to develope a successful process for producing high grade Ti02 from ilmenite. Commercial, as well as R and D processes to treat more abundant ilmenite ores fall in three general classess: 1. Iron in ilmenite is partially or completely reduced and separated either physically or chemically. 2. Iron is reduced to ferrous state and chemically leached away from the titanium. 3. Ore is treated to make chlorides either selectively or with subsequent separation and purification of $TiC_4$. Routes and efficiencies of these process technologies are primarily influenced by the particular ore deposit to be mined and secondly by environmental considerations. One deposit parameters which influence ilmenite process technologies are: 1. Complexity of microtextures of ilmenite intergrown with Fe-oxide minerals. 2. Composition of concentrates; ilmenites contain minor amounts of substituted Mg, Mn, and V. These elements plus iron and gangue minerals can cause difficulties to complete reactions, substantial acid consumption, difficulties of removing waste solids, and waste disposal problems. Major contributions to be made by petrologists for process optimization are: characterization and interpretation of compositional and physical changes of raw materials and solids derived from process streams. These informations can play significant role in selecting and improving process steps for titania production.

• Journal of Korean society of Dental Hygiene
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• v.6 no.3
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• pp.229-242
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• 2006

This study was conducted to find out basic information on better customer satisfaction and service by examining and analyzing in what routes patients mostly have selected their dental medical organizations and how they have reacted to their dissatisfaction. The subject of study included the patients who have come to dental clinics and dental hospitals to be treated in Cheonan City, Chungnam and the researcher of this study used a survey and analyzed its gathered data using an SPSS(Statistical Package for the Social Science) WIN 11.5 Program. As analysis methods, frequency and percentage were calculated to figure out the general characteristics of its subject. In addition, a ${\chi}^2$(Chi-square) test was performed to figure out the factors that patients have selected their dental medical organizations and the following results were obtained. 1. The largest number of patients selected their dental medical organizations by hearsay and more female and married patients selected them by hearsay than other patients, and there were significant differences(p<.05). 2. The dental patients put the priority on treatment techniques in their visiting hospitals and the patients who were more than 40 years old and married patients put more emphasis on treatment techniques in their visiting hospitals than other patients and there were significant differences(p<.05). 3. The said dental patients were not satisfied with the kindness of medical staffs in their visiting medical organizations; meanwhile, the patients who were aged below 30 and had an academic background of more than university degree and were unmarried were less satisfied with the kindness of medical staffs in their visiting medical organizations than other patients and there were significant differences(p<.05). 4. In terms of improvement methods or complaints, the largest number of them said that they just ignored and endured; meanwhile, the patients who were aged below 30 and had an education of more than university degree and were unmarried were more patient of improvement methods or complaints than other patients and there were significant differences(p<.05). 5. There were more patients who have introduced their visiting medical organizations to their neighboring people than the patients who have not done it; in the meantime, the patients who were aged over 40 and were married have introduced their visiting medical organizations to their neighboring people more than other patients(p<.05).

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.81-109
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• 1999

This study aims to reflect the basic principles and teaching-teaming principles of Realistic Mathematics Education in order to suppose an way in which mathematics as an activity is carried out in primary school. The development of what is known as RME started almost thirty years ago. It is founded by Freudenthal and his colleagues at the former IOWO. Freudenthal stressed the idea of matheamatics as a human activity. According to him, the key principles of RME are as follows: guided reinvention and progressive mathematisation, level theory, and didactical phenomenology. This means that children have guided opportunities to reinvent mathematics by doing it and so the focal point should not be on mathematics as a closed system but on the process of mathematisation. There are different levels in learning process. One should let children make the transition from one level to the next level in the progress of mathematisation in realistic contexts. Here, contexts means that domain of reality, which in some particular learning process is disclosed to the learner in order to be mathematised. And the word of 'realistic' is related not just with the real world, but is related to the emphasis that RME puts on offering the students problem situations which they can imagine. Under the background of these principles, RME supposes the following five instruction principles: phenomenological exploration, bridging by vertical instruments, pupils' own constructions and productions, interactivity, and interwining of learning strands. In order to reflect how to realize these principles in practice, the teaming process of algorithms is illustrated. In this process, children follow a learning route that takes its inspiration from the history of mathematics or from their own informal knowledge and strategies. Considering long division, the first levee is associated with real-life activities such as sharing sweets among children. Here, children use their own strategies to solve context problems. The second level is entered when the same sweet problems is presented and a model of the situation is created. Then it is focused on finding shortcomings. Finally, the schema of division becomes a subject of investigation. Comparing realistic mathematics education with constructivistic mathematics education, there interaction, reflective thinking, conflict situation are many similarities but there are alsodifferences. They share the characteristics such as mathematics as a human activity, active learner, etc. But in RME, it is focused on the delicate balance between the spontaneity of children and the authority of teachers, and the development of long-term loaming process which is structured but flexible. In this respect two forms of mathematics education are different. Here, we learn how to develop mathematics curriculum that respects the theory of children on reality and at the same time the theory of mathematics experts. In order to connect the informal mathematics of children and formal mathematics, we need more teachers as researchers and more researchers as observers who try to find the mathematical informal notions of children and anticipate routes of children's learning through thought-experiment continuously.

• School Mathematics
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• v.15 no.3
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• pp.619-632
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• 2013

One area where research is especially needed is their elaboration process and how they elaborate their idea as a group in a mathematical board game re-creation project. In this research, this process was named 'Mathematical Elaboration Process'. The purpose of this research is to understand how the gifted children elaborate their idea in a small group, and which idea can be chosen for a new board game when they are exposed to a project for making new mathematical board games using the what-if-not strategy. One of the gifted children's classes was chosen in which there were twenty students, and the class was composed of four groups in an elementary school in Korea. The researcher presented a series of re-creation game projects to them during the course of five weeks. To interpret their process of elaborating, the communication of the gifted students was recorded and transcribed. Students' elaboration processes were constructed through the interaction of both the mathematical route and the non-mathematical route. In the mathematical route, there were three routes; favorable thoughts, unfavorable thoughts and a neutral route. Favorable thoughts was concluded as 'Accepting', unfavorable thoughts resulted in 'Rejecting', and finally, the neutral route lead to a 'non-mathematical route'. Mainly, in a mathematical route, the reason of accepting the rule was mathematical thinking and logical reasons. The gifted children also show four categorized non-mathematical reactions when they re-created a mathematical board game; Inconsistency, Liking, Social Proof and Authority.

• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.32-37
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• 2015

Naturalized plants are invaded through various routes and distributed throughout the nation. They are also invaded in the sand dune ecosystem and poses a threat ecological niche of indigenous sand dune plants. We studied the effects of salt stress on the plant growth to suggest the management plans of naturalized plants in the sand dune ecosystem. As a result of germination experiment according to the salt gradient, germination rate decreased as the higher concentration and tolerance range was up to 160 mM. As a result of seedling experiment according to salt gradient, mortality rate was up to 90% from 0 mM to 200 mM and 100% over 300 mM. The day of first death with different concentration was 18.5 days in 100 mM and 6 days in 800 mM since the experiment has started. In addition, the day of last death with different concentration was 29.5 days in 100 mM and 6 days in 800 mM. Therefore, two stages of management plans would be effective. The first one is to suppress the germination by salt spray over 170 mM before germination. The other one is to wither seedlings in a short period by salt spray over 600 mM.

• Fire Science and Engineering
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• v.32 no.5
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• pp.46-51
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• 2018

The purpose of this study was to assess the evacuation route in a disaster information map to evacuate people to a shelter quickly and precisely during a disaster situation. For this purpose, this study examined the current status of domestic and international disaster information maps and related laws and conducted experiments to derive effective types of intersecting routes. The problems of the disaster information map were obtained through the first preliminary experiment and a survey. Based on these problems, experiments for each type were conducted to provide effective indication information for a disaster information map. To investigate the gait characteristics according to the number of crossing paths, the reduction rate in the crossing path was derived for each type by comparing the previous speed and passing speed. This will enable suggestions to judge the route quickly and accurately when determining the intersecting route in the search for an evacuation route. In conclusion, the experiment of this paper aims to make rapid and accurate evacuations using the disaster information map in response to disasters, and provide guidelines to citizens to contribute to a reduction of casualties.

• Journal of Radiation Protection and Research
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• v.14 no.1
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• pp.16-23
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• 1989

To obtain the basic data for protective roles and first-aid of radiation hazard, the present studies were carried out to evaluate the decontamination of radiostrontium by the First-Aid drugs. Each mouse was administered intraperitoneally dose of sodium alginate 5mg, $CaNa_3DTPA$ 8.4mg and saline 5ml following the internal contamination with 1 $\mu$Ci of strontium as $^{85}SrCl_2$. $^{85}Sr$ was determined by the radioactivity of body burden, urinary excretion, fecal excretion and organ distribution by Ge-detector and MCA. The results are summarized as follows. 1. Effective half life on whole body retention $^{85}Sr$ was determined at 33 hours. 2. The decontamination effect of First-Aid durgs on the body $^{85}Sr$ burden were increased $CaNa_3DTPA$ (4.7 times), sodium alginate (1.7 times) and saline (2.4 times) respectively. 3. Strontium were excreted through urine (35.4%), feces (64.4%) and other (0.2%). But on the $^{85}Sr$ excretion routes following First-Aid drugs treatment, strontium-85 mainly were excreted through urine after $CaNa_3DTPA$ and saline treatment, and was excreted through feces after sodium alginate treatment. 4. The organ distribution of strontium-85 is vertebra, femur, sternum and liver in order Finally, the extrapolations from these data to victims were suggested that the rapid administration of $CaNa_3DTPA$, sodium alginate and saline simultaneously were markedly increased the decontamination effects on the internal contamination of radiostrontium.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.408-420
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• 2010

On a Mobile Ad hoc NETwork(MANET), it is difficult to detect and prevent misbehaviors nodes existing between end nodes, as communication between remote nodes is made through multiple hop routes due to lack of a fixed networked structure. Therefore, to maintain MANET's performance and security, a technique to identify misbehaving middle nodes and nodes that are compromise by such nodes is required. However, previously proposed techniques assumed that nodes comprising MANET are in a friendly and cooperative relationship, and suggested only methods to identify misbehaving nodes. When these methods are applied to a larger-scale MANET, large overhead is induced. As such, this paper suggests a system model called Secure Cluster-based MANET(SecCBM) to provide secure communication between components aperANET and to ensure eed. As such, this pand managems suapemisbehavior nodes. SecCBM consists apetwo stages. The first is the preventis pstage, whereemisbehavior nodes are identified when rANET is comprised by using a cluster-based hierarchical control structure through dynamic authentication. The second is the post-preventis pstage, whereemisbehavior nodes created during the course apecommunication amongst nodes comprising the network are dh, thed by using FC and MN tables. Through this, MANET's communication safety and efficiency were improved and the proposed method was confirmed to be suitable for MANET through simulation performance evaluation.