• International Journal of Highway Engineering
• /
• v.15 no.5
• /
• pp.217-226
• /
• 2013

PURPOSES : Under the capacity conditions with balanced approach flows, roundabouts give less delay than existing signalized intersections; however, flows over 450 vehicles/hour/lane with unbalanced approach flow conditions, roundabouts efficiency drops due to the short time difference between the critical gap and the follow-up headway. The purpose of this study is developing a roundabout Signal Metering operation method by considering approach lanes degree of saturation. METHODS : A four-way-approach with one-lane roundabout is selected to compare the Signal Metering performance for the case of 16 different unbalanced flow conditions. Based on these traffic conditions, the performance is evaluated for 64 different cases of Signal Metering combinations by using SIDRA software. A degree of saturation(V/C ratio) sum for two adjoined approaches is used for the performance index of choosing Metered Approach and Controlling Approach. RESULTS : When the V/C ratio sum is 0.29~0.81 and Metered Approach flow is less than Controlling Approach flow, the average delay saving per vehicle is about 7 seconds; however, after this rage the delay saving decreases gradually until the V/C ratio sum reaches around 1.0. The range of V/C ratio sum 0.93~1.09 provides average delay saving per vehicle about 3 seconds. In case of V/C ratio sum is grater than 1.0 and the flows of Metered Approach is grater than Controlling Approach, the average delay per vehicle increases 3~11 times respectively. CONCLUSIONS : As expected, the Signal Metering provides substantial improvements in delay saving for the case of V/C ratio sum is 0.3~1.0 under the traffic flow conditions of Metered Approach is less than Controlling Approach.

• Journal of Integrative Natural Science
• /
• v.10 no.1
• /
• pp.51-57
• /
• 2017

The Taguchi parameter design in industry is an approach to reducing performance variation of quality characteristic in products and processes. In the Taguchi parameter design, the product array approach using orthogonal arrays is mainly used. It often requires an excessive number of experiments. An alternative approach, which is called the combined array approach, was studied. In these studies, only single response was considered. In this paper we propose how to simultaneously optimize multiresponse for the robust design using the combined array approach.

• Proceedings of the Korea Database Society Conference
• /
• 1999.06a
• /
• pp.403-413
• /
• 1999

Today's businesses are experiencing intensive global competition and the most accelerating pace of change ever. Competitors have sprung up that were not even on the business's radar. This environment impacts all decisions and strategies as business try to dominate their market or their industry merely to survive. So recently most of organizations are considering on building the data warehouse system to pursuit the business intelligence. We need the proper model to guide the approach to plan building data warehouse system when we want to plan it in considering the organizational status. Therefore we suggest a model to decide the approach to build data warehouse considering the project's environmental factors. First we review Ronald S. Swift(1998)'s five environmental factors that we have to consider when planing to build data warehouse. Then we propose a model to decide DW approach by the degree of those factors to be measured. DW approaches in this model are classified in conservative approach, technological approach, increasing approach. enterprise- wide approach, and ideal approach.

• Communications for Statistical Applications and Methods
• /
• v.8 no.3
• /
• pp.685-696
• /
• 2001

Robust design is an approach to reducing performance variation of response values in products and processes. In the Taguchl parameter design, the product-array approach using orthogonal arrays is mainly used. However, it often requires an excessive number of experiments. An alternative approach, which is called the combined-array approach, was suggested by Welch et. al. (1990) and studied by others. In these studies, only single response variable was considered. We propose how to simultaneously optimize multiple responses when there are correlations among responses, and when we use the combined-array approach to assign control and noise factors. An example is illustrated to show the difference between the Taguchi's product-array approach and the combined-array approach.

• English Language & Literature Teaching
• /
• v.10 no.1
• /
• pp.179-200
• /
• 2004

The purpose of this study is to investigate the adequacy of derivational approach and representational approach to syntactic theories in generative grammar. As the generative grammar is based on the derivational process of syntactic theories, it is suggested that derivational approach is more valid than representational approach. Move, Economy Principle, Local Economy and Label-free Phrase Structure in Minimalist framework support the preference of derivational approach to representational approach with the elimination of computational complexity, minimality, and label-free phrase structure. Syntactic structure is considered as the result of the interaction of the properties of lexical items containing probe and economy conditions constrained by bare output conditions. On the other hand, Pseudogapping in Lasnik(1999) is analyzed in terms of Object Shift, that is, overt raising to Spec of $Agr_o$ and the PF deletion of VP in representational approach. Hence, it is suggested that the combination of derivational and representational approaches to syntactic theories can be admitted in generative grammar.

• Speech Sciences
• /
• v.11 no.4
• /
• pp.207-221
• /
• 2004

There are two different approaches in studying mapping between syntactic structure and prosody, the 'phonetic approach' and the 'phonological approach'. An experiment to examine which approach is more valid was conducted. In the experiment, syntactically ambiguous Seoul Korean sentences in each of which a noun immediately after an adjective starts with either an H-segment (a segment which triggers the AP-initial H tone) or an L-segment (a segment other than H-segments) were recorded. by 3 Seoul Korean speakers. The F0 values in the syllables containing the consonants in question were then measured. The results show that interaction between the segment type and the branching structure is statistically significant. which suggests that it is difficult to use the phonetic .approach to generalize the relationship between syntax and prosody. Thus, it is concluded that the phonological approach is more valid.

• Structural Engineering and Mechanics
• /
• v.30 no.1
• /
• pp.37-66
• /
• 2008

This paper focuses on the nonlinear vibrations of stay cables and evaluates the dynamic characteristics of stay cables by using the nonlinear enhanced MECS approach and the approximate approach. The nonlinear enhanced MECS approach is that both the girder-tower vibrations and the cable vibrations including parametric cable vibrations are simultaneously considered in the numerical analysis of cable-stayed bridges. Cable finite element method is used to simulate the responses including the parametric vibrations of stay cables. The approximate approach is based on the assumption that cable vibrations have a small effect on girder-tower vibrations, and analyzes the local cable vibrations after obtaining the girder-tower responses. Under the periodic excitations or the moderate ground motion, the differences of the responses of stay cables between these two approaches are evaluated in detail. The effect of cable vibrations on the girder and towers are also discussed. As a result, the dynamic characteristics of the parametric vibrations in stay cables can be evaluated by using the approximate approach or the nonlinear enhanced MECS approach. Since the different axial force fluctuant of stay cables in both ends of one girder causes the difference response values between two approach, it had better use the nonlinear enhanced MECS approach to perform the dynamic analyses of cable-stayed bridges.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1991.06a
• /
• pp.39-39
• /
• 1991

뇌하수체 종양에 대한 경비중격 경접형동 수술은 1907년 Schloffer가 비절개수술에 의한 방법을 보고한 이래 1914년 Cushing이 sublabial approach를 정립하였으나, 이후 약 반세기 동안 경비중격 경접형동 수술이 개두술에 비해 종양의 재발율이 높다는 이유로 기피되어왔다. 1968년에 이르러 Cottle의 maxilla-premaxilla approach로 비중격에 대한 수기가 축적되고 수술현미경의 발달로 미세수술이 도입되면서 경비중격 경접형동수술이 다시 각광을 받게 되었다. 이후 sublabial approach, alotomy approach, columellar approach, external rhinoplasty approach 등이 개발되어 보고되었으며 접형동의 함기화가 불완전한conchal 형이나 터어키안 상측부로의 종양의 확장이 심한 예를 제외하고는 모두 이 방법으로 수술을 시행하는 것이 보편화되어 있으며 문헌고찰에 의하면 개두술시의 술후 사망율이 17%인데 비해 경비중격 경접형동술의 경우 1.8%라고 보고되고 있다. 서울대학교병원 이비인후과에서는 sublabial approach로 터어키안까지 종양을 노출시킨 후 신경외과의와 공동으로 뇌하수체 종양을 치료한 예를1977년부터 1988년까지 135례를 보고한 바 있다. 최근에는 sublabial approach의 단점을 보완하면서 외비의 해부학적인 구조에 익숙해질 수 있는external rhinoplasty approach를 이용하여 경비중격 경접형동 수술을 시행하고 있으며 1977년부터의 치험례를 임상분석하여 특히 external rhinoplasty approach의 수술성적을 보고하는 바이다.

• Archives of Plastic Surgery
• /
• v.35 no.2
• /
• pp.152-158
• /
• 2008

Purpose: Mandibulotomy approach and mandible sparing approach are most common methods for oropharyngeal cancer surgery. Good surgical view and convenience of flap inset are advantages of mandibulotomy approach but deformity of mandible contour, postoperative malocclusion and radionecrosis are its limitations. To make up for the limitations, mandible sparing method is commonly performed, but limited surgical view and difficulties of flap inset are the weak points of this approach. The purpose of the study is to compare mandibulotomy and mandible sparing approaches in postoperative complications and progression of the treatment in oropharyngeal cancer operation and reconstruction. Methods: Single reconstructive microsurgeon operated for oropharyngeal cancer patients with different surgeons of head and neck department who prefer mandibulotomy and mandible sparing approach respectively, and we compared the frequency of postoperative complication, operation time, duration of hospitalization and recurrence rate between two different surgical approaches. Results: Mandibulotomy approach was used in 18 patients and mandible sparing approach was used in 15 patients. In mandibulotomy approach, there happened one case of teeth injury and one case of necrosis of skin and gingiva, but there happened no malocclusion and radionecrosis. In mandible sparing approach, there were 3 cases of fistula and 2 cases of infection which are significantly higher than mandibulotomy approach. There were no significant differences between early regional recurrence and duration of hospitalization. Conclusion: In this study we compared two different methods for the surgical approach in oropharyngeal cancer surgery. As mandible sparing approach has difficulties of limited surgical view, it can be used for the limited indications of anterior tongue and mouth floor cancer. Mandibulotomy approach has advantages of good surgical view and convenience of flap inset. In this method preservation of gingival tissue, watertight fashion suture, delicate osteotomy and plate fixation to maintain occlusion are the key points for the successful results.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.2
• /
• pp.166-172
• /
• 2001

We construct several supercategories of ACHY (of approach Cauchy spaces) and AULim (of approach uniform limit spaces) and investigate the relation among them.