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Petri Net Modeling and Analysis for Periodic Job Shops with Blocking

  • Lee, Tae-Eog;Song, Ju-Seog
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1996.04a
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    • pp.314-314
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    • 1996
  • We investigate the scheduling problem for periodic job shops with blocking. We develop Petri net models for periodic job shops with finite buffers. A buffer control method would allow the jobs to enter the input buffer of the next machine in the order for which they are completed. We discuss difficulties in using such a random order buffer control method and random access buffers. We thus propose an alternative buffer control policy that restricts the jobs to enter the input buffer of the next machine in a predetermined order. The buffer control method simplifies job flows and control systems. Further, it requires only a cost-effective simple sequential buffer. We show that the periodic scheduling model with finite buffers using the buffer control policy can be transformed into an equivalent periodic scheduling model with no buffer, which is modeled as a timed marked graph. We characterize the structural properties for deadlock detection. Finally, we develop a mixed integer programming model for the no buffer problem that finds a deadlock-free optimal sequence that minimizes the cycle time.

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끊김앞에서 보이는 서울말의 억양특징

  • Yun Il-Seung
    • MALSORI
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    • no.21_24
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    • pp.90-110
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    • 1992
  • The purpose of this thesis is to investigate the intonation features of the last two syllables of rhythmic units, with the exception of the sentence final unit, in the Seoul dialect of Korean. The Model 5500 Sona-graph was used to measure the pitch and duration of the target syllables. There are two classes of materials. One class was designed to determine the intonation of rhythmic units in a natural situation and the other to investigate the intonation of rhythmic units in an artificial situation, in which speakers were asked to read the materials pausing only at the marked boundaries, with a view to identifying the intonation of Seoul dialect more clearly. The findings of this investigation are as follows: (1) Korean averages an 11% rising intonation between the two syllables at the end of a rhythmic unit. (2) The rising rate between the final two syllables' pitch values at the subject rhythmic unit is generally higher than those at other units in a sentence and it seems to be meaningful syntactically. (3) Before a boundary the rhythmic units undergo 'pre-lowering', in which the pitch gradually lowers from the first syllable to the penultimate. (4) Every syllable in each rhythmic unit tends to lengthen when speakers read the materials with a pause between units and the tendency is most salient at the final syllable before a boundary.

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Hardware implementation of Petri net-based controller with matrix-based look-up tables (행렬구조 메모리 참조표를 사용한 페트리네트 제어기의 하드웨어 구현)

  • Chang, Nae-Hyuck;Jeong, Seung-Kweon;Kwon, Wook-Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.2
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    • pp.194-202
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    • 1998
  • This paper describes a hardware implementation method of a Petri Net-based controller. A flexible and systematic implementation method, based on look-up tables, is suggested, which enables to build high speed Petri net-based controllers. The suggested method overcomes the inherent speed limit that arises from the microprocessors by using of matrix-based look-up tables. Based on the matrix framework, this paper suggests various specific data path structures as well as a basic data path structure, accompanied by evolution algorithms, for sub-class Petri nets. A new sub-class Petri net, named Biarced Petri Net, resolves memory explosion problem that usually comes with matrix-based look-up tables. The suggested matrix-based method based on the Biarced Petri net has as good efficiency and expendability as the list-based methods. This paper shows the usefulness of the suggested method, evaluating the size of the look-up tables and introducing an architecture of the signal processing unit of a programmable controller. The suggested implementation method is supported by an automatic design support program.

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A Study on stylistic measurement of Chogori with Museum specimens (유물실측을 통한 여자저고리의 치수연구)

  • 유송옥
    • Journal of the Korean Society of Costume
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    • v.32
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    • pp.21-30
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    • 1997
  • Chogori the basic upper garment of korea costume occupies an important role in tra-ditional dressing and continues to be in use to the present days. Of course there has been changes in the length and line of Chogori with the flow of time based on the Ancient Yoo. This is a study of the 14 parts of Chgori based on statistical analysis by computing the practical measuements. Here the statistical analysis is a objective and quantitative of the stylistic changes in Chogori with time. In this study from the data the Mean and Standard deviation has been evaluated and periodic change is shown by graph to test the periodic change T-test Regressional analysis Index analysis has been used. The results are as follows: 1. The length of clothing has changed with time except the sleeve length. Here the length of clothing means all the other measurements ex-cept the sleeve Thus while the measurements of sleeve length has been uniquely unchanged the other measurements have influenced each other. 2. Generally the form of Chogori had the tendency towards smallness in the 19th cen-tury. But it tended to get larger in the 20th century. 3. Compared to other periods the mode of 19th and 20th century Chogori was widely ac-cepted as the Standard deviation of that period was very narrow. 4. The results seen from the regressional analysis of the Cho-sun period woman's Chogori satisfy the t-value and R-squared and thus support the regression formula presump-tion. 5. From the index analysis it is revealed that with decrease in the armhole measurement sleeve measurement and neckband; relatively same decrease in the wrist measurement; and very marked decrease in the sideline measurement.

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Analysis on the Trend in Customers' Consciousness as Appeared in Wellbeing Trend, LOHAS -Mainly in Food, Clothing, and Shelter Based Websites- (웰빙 트렌드 로하스(LOHAS)에 나타난 소비자 의식 변화에 따른 웹 디자인 발전방향 분석 - 의, 식, 주 웹 사이트를 중심으로 -)

  • Kim, Min-Seo;Chun, Yang-Deok
    • Archives of design research
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    • v.20 no.3 s.71
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    • pp.49-60
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    • 2007
  • As the world is in the age of globalization and information, we observe diverse changes in the market environment. Since wide-spread internet services and global networks made ubiquitous learning and business possible, equalizing consumers' ideology and preference, new trend and life style could be introduced easily. This study stipulates on the theoretical concept of the wellbeing consumer and LOHAS consumer. Consumers of LOHAS could be sampled out through pre-questionnaire targeting at selected food, clothing, and shelter based on companies of both wellbeing and general brands. Through this it is attempted to measure wellbeing emotion, recognition quotient of emotion and reason, affirmation and negation, mental emotion quotient, and preference in order to find out their value and to ultimately come up with what web design should be aiming at. Conclusions are as follows: Firstly, consumers easily recognize emotional identification from the web pages of wellbeing brand, rather than that of general brands. Secondly, what web pages of wellbeing brand recognize is reason, not emotion. Thirdly, the design of wellbeing brands scored higher than those of general brands in terms of positive aspects such as hospitality and familiarity, and high mental emotion quotient could not affect the consumers' preference toward web design. Fourthly, wellbeing brands win more preference than general brands do, and preference becomes higher after customers' visit to web pages basically. Lastly, sampled emotional adjectives toward the web designs of wellbeing brands marked a aesthetic graph figure, without leaning toward an active or stable one. It is expected that this study can serve as a groundwork to create proper strategies to actively involve consumers in industrial sphere.

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FLEXURAL STRENGTH OF IMPLANT FIXED PROSTHESIS USING FIBER REINFORCED COMPOSITE (섬유성 강화 컴포지트를 사용한 임플랜트 고정성 보철물의 굴곡강도)

  • Kang, Kyung-Hee;Kwon, Kung-Rock;Lee, Sung-Bok;Choi, Dae-Gyun
    • The Journal of Korean Academy of Prosthodontics
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    • v.44 no.5
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    • pp.526-536
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    • 2006
  • Statement of problem : Use of fiber composite technology as well as development of nonmetal implant prosthesis solved many problems due to metal alloy substructure such as corrosion. toxicity, difficult casting, expensiveness and esthetic limit. After clinical and laboratory test, we could find out that fiber-reinforced composite prostheses have good mechanical properties and FRC can make metal-free implant prostheses successful. Purpose : The purpose of this study is to evaluate the flexural strength of implant fixed prosthesis using fiber reinforced composite. Material and methods : 2-implant fixture were placed in second premolar and second molar area in edentulous mandibular model, and their abutments were placed, and bridge prostheses using gold, PFG, Tescera, and Targis Vectris were fabricated. Tescera was made in 5 different designs with different supplements. Group I was composed by 3 bars with diameter 1.0mm and 5 meshes, 2 bars and 5 meshes for Group II, 1 bar and 5 meshes for Group III, and only 5 meshes were used for Group IV. And Group V is composed by only 3 bars. Resin (Tescera) facing was made to buccal part of pontic of gold bridge. All of gold and PFG bridges were made on one model, 5 Targis Vectris bridges were also made on one model, and 25 Tescera bridges were. made on 3 models. Each bridge was attached to the test model by temporary cement and shallow depression was formed near central fossa of the bridge pontic to let 5 mm metal ball not move. Flexual strength was marked in graph by INSTRON. Results : The results of the study are as follows. The initial crack strength was the highest on PFG. and in order of gold bridge Tescera I, Tescera II, Targis vectris, Tescera IV, Tescera III, and Tescera V. The maximum strength was the highest on gold bridge, and in order of PFG, Tescera I, Tescera IV Tescera II, Targis vectris, Tescera III, and Tescera V. Conculsions : The following conclusions were drawn from the results of this study. 1. Flextural strength of implant prosthesis using fiber reinforced composite was higher than average posterior occlusal force. 2. In initial crack strength, Tescera I was stronger than Tescera V, and weaker than PFG. 3. Kinds and number of auxillary components had an effect on maximum strength, and maximum strength was increased as number of auxillary components increased. 4 Maximum strength of Tescera I was higher than Targis vectris, and lower than PFG.

Case Studies of Comparing EN 954-1 and EN ISO 13849-1 Standard for Design of Industrial Machinery Safety Control System

  • Kim, Tae-Ho;Kim, Hong-Ki;Yoon, Hoon Yong
    • Journal of the Ergonomics Society of Korea
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    • v.32 no.3
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    • pp.279-291
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    • 2013
  • Objective: The aim of this study was to compare old standard EN 954-1 and new standard EN ISO 13849-1 through case study and provide necessity of adaptation of EN ISO 13849-1 in Korea. Background: International and EU harmonized standard EN ISO 13849 "safety of machinery - Safety-related parts of control system" is classified into Part 1: General principles for design and Part 2: Validation. EN ISO 13849-1 standard was introduced in Official Journal of the European Union on September 8, 2009 as harmonized standard, and old standard EN 954-1 was withdrawn on December 31, 2011. So, EU decided to use of EN ISO 13849-1 standard forcibly from January 1, 2012 for safety of machinery. New machines need to be CE marked if they are to be placed on the market in the European Economic Area(EEA), Switzerland or Turkey, and Korean machine builder should apply EN ISO 3849-1 standard for safety of machinery accordingly. However, current Korean Safety Certification system(KCs mark) for dangerous machinery is not referred to EN ISO 13849-1 standard as safety standard. There is a need of research for adaptation of EN ISO 13849-1 standard in Korea as safety standards for new design of safety-related control system which use mostly electronic components. Method: Five case studies of representative designs for safety-related control system in accordance with EN 954-1were selected according to safety category from B to 4. And these five representative designs were tried to change new design in accordance with EN ISO 13849-1 standard. The results of comparison were analyzed in aspect of economy and technical complexity. Results: The results showed that EN ISO 13849-1 provided quantitative method of application and it enabled designers to create safety-related control systems that require fewer components and less wiring, with many of the components being to a lower specification and, therefore, less costly. Conclusion: EN ISO 13849-1 standard is good for electronic safety-related control systems compare to EN 954-1. By considering the importance of application of EN ISO 13849-1 and benefits, the application of EN ISO 13849-1 as safety standard for safety of machinery is urgent in Korea. Application: The results of comparing EN 954-1 and EN ISO 13849-1 standard might help to determine the adaptation of EN ISO 13849-1 standard for safety of industrial machinery in Korea.

Peer Relationship Problems in Relation to Children's Peer Status (아동의 또래지위에 따른 교우관계문제)

  • Jeong, Seong-Cheol;Hong, Sang-Hwang;Kim, Jong-Mee
    • The Korean Journal of Elementary Counseling
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    • v.10 no.2
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    • pp.167-184
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    • 2011
  • This study has investigated how five peer status groups that were selected by a social skills scale exhibit different peer relationship problems by means of averages, standard deviations, and profile analysis. Social skills scale developed by Yi-Hwan Ahn(2007) and the inventory of peer relationships by Hae-Won Jung(2007) were administered to 551 fifth and sixth graders in 9 elementary schools located in Gyungnam province, and averages and standard deviations of 5 peer status groups' peer relationship problems were explored. Also in order to see if differences exist among 8 sub-scales in the inventory of peer relationships according to the peer status, an average profile of scores was represented by a graph and multivariate analysis was carried out. The main results of the study are as follows. First, statistical analysis of 551 cases included in the study showed the children were distributed into the Average group(319, 57.9%), the Popular group(111, 29.1%), the Rejected group(70, 12.9%), the Controversial group(41, 7.4%), and the Neglected group(10, 1.8%), in that order. Second, as a result of comparing average scores for each measure in the inventory of peer relationships according to the peer status group, a significant difference was found to exist according to a child's peer status. The Popular group showed the lowest scores in Too Controlling, Hard to be Supportive, the Cold, and Non-Assertive among the 5 peer status groups whereas the Rejected group showed the highest scores in Social Avoidant, Non-Assertive, and Too Responsible. Third, marked differences according to the peer status group were found. The Popular group showed the lowest profile among the peer status groups whereas the Rejected group had the highest profile. In the sub-scales of the peer relationship problems, the Rejected children showed a significantly higher level of Socially Avoidant and Non-Assertiveness in comparison to the Popular children, which implies the Popular children group has lower levels of peer relationship problems than the other groups.

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Comparison of Center Error or X-ray Field and Light Field Size of Diagnostic Digital X-ray Unit according to the Hospital Grade (병원 등급에 따른 X선조사야와 광조사야 간의 면적 및 중심점 오차 비교)

  • Lee, Won-Jeong;Song, Gyu-Ri;Shin, Hyun-yi
    • Journal of the Korean Society of Radiology
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    • v.14 no.3
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    • pp.245-252
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    • 2020
  • The purpose of this study was intended to recognize the importance of quality control (QC) in order to reduce exposure and improve image quality by comparing the center-point (CP) of according to hospital grade and the difference between X-ray field (XF) and light field (LF) in diagnostic digital X-ray devices. XF and LF size, CP were measured in 12 digital X-ray devices at 10 hospitals located in 00 metropolitan cities. Phantom was made in different width respectively, using 0.8 mm wire after attaching to the standardized graph paper on transparent plastic plate and marked as cross wire in the center of the phantom. After placing the phantom on the table of the digital X-ray device, the images were obtained by shooting it vertically each field of survey. All images were acquired under the same conditions of exposure at distance of 100cm between the focus-detector. XF and LF size, CP error were measured using the picture archiving communication system. data were expressed as mean with standard error and then analyzed using SPSS ver. 22.0. The difference in field between the XF and LF size was the smallest in clinic, followed by university hospitals, hospitals and general hospitals. Based on the university hospitals with the least CP error, there was a statistically significant difference in CP error between university hospitals and clinics (p=0.024). Group less than 36-month after QC had fewer statistical errors than 36-month group (0.26 vs. 0.88, p=0.036). The difference between the XF and LF size was the lowest in clinic and CP error was the lowest in university hospital. Moreover, hospitals with short period of time after QC have fewer CP error and it means that introduction of timely QC according to the QC items is essential.

The Changing Patterns of Demand-Supply and Role of Mineral Resources in Economic Growth during Industrialization of the Republic of Korea (한국공업화과정(韓國工業化過程)에서의 광물자원(鑛物資源)의 수급구조변화(需給構造變化)와 경제성장(經濟成長)에 있어서의 역할(役割))

  • Yun, Suckew
    • Economic and Environmental Geology
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    • v.18 no.1
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    • pp.65-92
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    • 1985
  • A total of 12 mineral commodities significant in domestic output, economy and/or strategy of the Republic of Korea are chosen to examine the structural changes in production and demand-supply of these minerals during the last two decades of her industrialization. These include iron and manganese ores as the raw materials for iron and steel making, copper, zinc and tungsten ores among other non-ferrous metallic minerals, limestone (cement), kaolin, talc, pyrophyllite and graphite among other non-metallic minerals, and anthracite coal as the only domestic source of fossil energy. These are reviewed historically in time-series based on the statistical data which are tabulated and graphed in terms of domestic output, export, import, apparent demand-supply, its increasing rate, and self-sufficiency rate of each commodity. The increasing rates of demand-supply (IRDS) of some more important commodities are compared with those of Gross Domestic Production (GDP) and Economic Growth Rate (EGR) to evaluate how the IRDS contributed to the GDP and EGR. The major results revealed are as follows: Among the 12 commodities, the domestic output of 8 commodities appeared to have grown with steady upward trends: they are ores of lead, zinc and tungsten, limestone (cement), kaolin, talc, pyrophyllite and anthracite coal. Two commodities, ores of iron and copper, continued with unchanging or slightly declining trends and varied fluctuations, in spite of their cardinal importance to the heavy industry and strategy of Korea. The remaining two, graphite and manganese ore, have gradualy declined in domestic output in which the former has still enough resource potential but the latter has not and virtually ceased its domestic output. Trade patterns for mineral commodities in the Republic of Korea during the last two decades have changed greatly, being marked by a shift from mineral-exporting to mineral importing, mainly because of increasing consumption of mineral raw materials for industrialization rather than beceuse of decreasing output of domestic mineral commodities in quantity. In terms of trade patterns, the 12 commodities concerned in this study can be classified into the following four groups. The 1st group - ores of lead and tungsten have only been exported without imports. The 2nd group - amorphous graphite, and pyrophyllite have mainly been exported but partly been imported. The 3rd group - kaolin, talc and crystalline graphite have equally been exported and imported, but quantity of imports have rapidly been increased with time. The 4th group - ores of iron, manganese and zinc have shifted from exports to imports during the industrialization, particularly owing to the initiation of iron and steel making by the Pohang Iron and Steel Company in the middle 1970' s and the new establishment of the Onsan Zinc Refinery in the late 1970' s. All of the 12 commodities under considerations were far above 100% in self-sufficiency rate before or in the early 1960' s. Recently, however, most of them have been declined to below 100% except for those of limestone (cement) and pyrophyllite. It is particularly serious to identify that the self-sufficiency rates of the three important metallic minerals, iron, copper and manganese ores in 1982 appeared to be 5.1%, 0.5%, and 0.01%, respectively. The average self-sufficiency rate of the total domestic minerals produced in 1982 was 14.4% (in value) for that year. Mining industry appeared to be extremely high in its intermediate demand rate whereas its intermediate input rate to be quite low indicating that mineral raw materials have been exerted strong forward linkage effects upon the other industries rather than backward linkage effects. In comparing the curves of increasing rates of demand-supply of several major minerals - iron ore, manganese ore, copper ore, limestone (cement), kaolin, and anthracite coal - with those of Gross Domestic Production and Economic Growth Rate drawn on every graph, it is clearly shown that the curves of increasing rates of demand-supply comprise around 6 to 7 periods of cycles which roughly harmonious with those of the curves of GDP and EGR, except for the curve of anthracite coal of which the configuration seems to have resulted from the (artificial) government's mineral policy rather than from economic free market mechanism. The harmonic feature of these curves well suggests that the increasing rates of demand-supply of major minerals have been significantly contributed to the GDP and EGR. In addition, the wider amplitudes of the iron, manganese and copper curves than those of the limestone (cement) and kaolin curves indicate that the contribution of the former, metallic commodities, has been greater than that of the latter, non-metallic commodities.

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