• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.136-139
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• 2011

The conventional semiconductor equipment has adopted SRAM module as the test pattern memory, which has a simple design and does not require refreshing. However, SRAM has its disadvantages as it takes up more space as its capacity becomes larger, making it difficult to meet the requirements of large memories and compact size. if DRAM is adopted as the semiconductor inspection equipment, it takes up less space and costs less than SRAM. However, DRAM is also disadvantageous because it requires the memory cell refresh, which is not suitable for the semiconductor examination equipments that require correct timing. Therefore, In this paper, we will proposed an algorithm for punctuality guarantee of memory-free inspection equipment using DDR2 SDRAM. And we will produced memory controller using punctuality guarantee algorithm.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.6-10
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• 2011

This article deals with a problem of setting reliability targets of the railroad systems where the punctuality target is given to the operator and a penalty is imposed for the year when the target is not met. The operator should set the reliability targets of the railroad system and sub-systems because the reliability affects the expected number of years when the penalty is imposed. This paper presents a procedure for setting the service reliability target and equations to calculate the expected number of years when the penalty is imposed and the probability that the operator should pay the penalty per year according to the mean kilometer between service failures of the railroad system and sub-systems.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.112-123
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• 2017

The accurate forecasting of the public transportation's transit and arrival time has become increasingly important as more people use buses and subways instead of personal vehicles under the government's public transportation promotion policy. Using bus management system (BMS) data, which provide information on the real-time bus location, operation interval, and operation history, it is now possible to analyze the bus schedule reliability. However, the punctuality should always be considered together with the operation safety. Therefore, this study suggests a new methodology to secure both reliability and safety using the BMS data. Unlike other studies, we calculated the bus travel time between two bus stops by dividing the total travel length into 6 sections using 5 different measuring points. In addition, the optimal travel time for each bus route was proposed by analyzing the mean, standard deviation and coefficient of variation of the each section's measurement. This will ensure the reliability, safety and mobility of the bus operation.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2646-2648
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• 2005

열차는 타 교통수단에 비하여 정시성과 안전성이 우수하다는 장점을 가지고 있다. 이러한 열차의 정시성을 유지하는데 있어서 열차 경합에 대한 대응은 매우 중요한 용소이다. 열차 경합은 열차와 열차간의 충돌로 정의된다. 이러한 열차의 경합은 두 열차의 각 역에서의 도착 및 출발시각을 변경함으로써 해결할 수 있다. 본 논문에서는 전문가 시스템 및 제약조건 만족 기법을 이용하여 열차 경합을 해소하는 알고리즘을 제시한다.

• Journal of the KSME
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• v.51 no.8
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• pp.44-48
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• 2011

철도 이해관계자인 승객, 정부, 운영사 그리고 제작사가 철도서비스에 요구하는 핵심적인 품질인자인 안전성, 정시성, 서비스 공급비용 등은 철도시스템의 신뢰성과 밀접한 관계가 있으므로 이들을 만족시키기 위해서는 체계적인 신뢰성 관리활동이 필요하다.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.151-160
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• 2005

In case of public transit such as bus system, the probability concept is used to evaluate the Level-of-Service of the operations. And each levels could be classified according to the linear probability value. (TCQSM: Transit Capacity and Quality of Service Manual-2nd Edition, TRB, Washington DC., 2003) In this case, the drivers or passengers wouldn't think that the service level isn't equivalent to the linear probability value. Thus the linear probability value doesn't exactly reflect the service level. This study shows the problems of using the linear probability value in classifying the service level through the case of evaluation of bus operation's punctuality, presented in TCQSM. To make up for the problems of such case, two methodologies are presented in this study. The method of determining Level-of-Service criteria using probability density of headway variation's distribution, presented in this paper, adequately reflects passenger's expected waiting time. According to the application result to real bus operation data, it tis better than the method of TCQSM to evaluate the reliability of bus operations. However further research about the relations between utility difference and passenger feeling of service level in necessary to apply the method that uses the utility function. It remains as the limitation of this paper.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.3
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• pp.229-235
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• 2005

The results of having studied the relationships between environmental factors and family history which affected distribution of ametropia according to departments are like these. The subjects of study were 920 persons who were the industrial high school students in Daejeon. First, When we searched ametropia degree and congenital factors, expecially in case of emmetropia, it showed that the students' parents who wore glasses amounted to 22.6% in ratio and the students' brothers and sisters wore glasses in 22.8%. But in case of the students of ametropia, their parents' rate of wearing glasses was 27.7%. The result showed that refractive error status of offsprings was related to their parents' eye condition. Second, We studied emmetropia and ametropia who used computer for over 3 hours in order to see relationships between refractive error and acquired factors. The emmetropias were 45.6%, while the ametropias were 70.1%. The result showed that it appeared 24.5% more in ametropia. In the end, refractive error can be greatly influenced by environmental factors. Third, The result of comparing distribution of ametropia with VDT using time according to each department showed the students of constructional information department had much more ametropia rate. They used computers than any other students in taking lessons and spent much more time than other department's students.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.59-63
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• 2009

Purpose: To investigate the near horizontal heterophoria of the college students in their twenties on north Kyonggi Province. Methods: The all subjects had not experienced any ocular surgery and have no disease and their mean age is 22.9. As 122 subjects, they are 50 emmetropes and 72 ametropes. The ametropes are all myopia. After distance visual acuity correction with subjective and objective refraction test, evaluated their horizontal heterophoria with red maddox rod. Results: In maddox rod test, the subjects consist of orthophoria 4.9%, esophoria 9.8% and exophoria 85.3%. In the emmetropes orthophoria is 8%, esophoria is also 8% and exophoria is 84%. In the ametropes orthophoria is 2.8%, esophoria is 11.1% and exophoria is 86.1%. The mean size of horizontal heterophoria is esophoria 3.59PD (prism diopter), exophoria 7.04PD and in the emmetropes esophoria is 3.25PD, exophoria is 6.60PD. In the ametropes esophoria is 3.75PD and exophoria is 7.34PD. Conclusions: In the emmetropoes the orthophoria is more than in the ametropes and the esophoria and exophoria is more in the ametropes. But the differences between the heterophoria and emmetropia or ametropia were not significant (p>0.05). The mean size of heterophoria is higher in the ametropes than in the emmetropoes. The distribution range of heterophoria is wider in the male subjects than the female subjects.

• The Journal of Korean Philosophical History
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• no.59
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• pp.343-370
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• 2018

Jeong Si-Han(丁時翰) completed "Siqibianzheng"("四七辨證") at the age of 72, and later had the argument over Runwuxingtongyilunzheng(人物性同異論爭) with his disciple, Lee Sik(李?). Jeong Si-Han(丁時翰) had the position of Runwuxingyilun(人物性異論) and Lee Sik(李?) Runwuxingtonglun(人物性同論). Yet, the argument over Runwuxingtongyilunzheng(人物性同異論爭) had been forgotten and "Siqibianzheng"("四七辨證") could be acknowledged because Toegye school(退溪學派) and Yulgok school(栗谷學派) were conflicting and criticizing each other's stance at that time. It seems like Lee Hyeon-Il(李玄逸)'s "Liqulishilunsiduanqiqingshubian"("栗谷李氏論四端七情書辨") had a great influence on the completion of "Siqibianzheng" ("四七辨證"). Lee Yi(李珥)'s thought of Siduan(四端) and Qiqing(七情) was 'the position of Hunlun(渾淪)' that 'Qiqing(七情) includes Siduan(四端)', and Lee Hwang(李滉) had the 'position of Fenkai(分開)' that Siduan(四端) and Qiqing(七情) should be interpreted differently. Jeong Si-Han(丁時翰) criticized the stance of Hunlun(渾淪) from the position of Fenkai(分開). What did Jeong Si-Han(丁時翰) try to pursue through "Siqibianzheng"("四七辨證")? This fact tends to make us forget the controversy over Runwuxingtongyilunzheng(人物性同異論爭) between Jeong Si-Han(丁時翰) and disciple Lee Sik(李?). Now we know the fact that Jeong Si-Han(丁時翰) criticized Lee Yi(李珥) in "Siqibianzheng"("四七辨證"), but don't care much about the fact that Jeong Si-Han(丁時翰) caused the controversy over Runwuxingtongyilun(人物性同異論). Why "Siqibianzheng"("四七辨證") has remained in our memory even though it was an important one? It might be because "Siqibianzheng"("四七辨證") had an impact on Lee Sik(李?), Shin Hu-Dam(愼後聃), and even Jeong Yak-Yong(丁若鏞) in the process of summarizing the arguments over Siduanqiqinglunzheng(四端七情論爭) since Jeong Si-Han(丁時翰) regardless of whether Jeong Si-Han(丁時翰) had hoped it or not.

• 한국도로학회:학술대회논문집
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• 2011.03a
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• pp.235-242
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• 2011