• 대한기계학회논문집B
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• 제30권12호
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• pp.1218-1227
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• 2006

In this paper a parametric study using an immersed boundary method has been carried out to investigate the effects of stable density stratification on the wakes past two identical three-dimensional hills aligned in tandem. The Reynolds number based on the uniform inlet velocity and twice the hill height was fixed at Re=300 while the Froude number based on the inlet velocity and the hill height was retained at Fr=0.2. Neutral flow without density stratification was also computed for comparison. Under a strong stratification, vertical motion of fluid particles over the three-dimensional hills is suppressed and the wake structures behind the hills become planar. Depending on the distance between the two hills, the flow pattern of each wake is significantly affected by the stratification. There is a critical hill distance at which flow characteristics drastically change. Qualitative and quantitative features of the wake interaction are reported.

• International Journal of Knowledge Content Development & Technology
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• 제10권3호
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• pp.51-68
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• 2020

The library provides its services to satisfy the user's approach. Naturally, the development of library services may determine by considering the satisfaction of users. It traces users' perceptions regarding subject access highlighting problems in the retrieval of Bengali documents by subject. This study has designed to assess users' attitudes towards the retrievals of Bengali documents in OPAC through subject headings. For a collection of data, a representative sample has drawn from a large and heterogeneous population consisting of users in university libraries of West Bengal using a stratified sampling technique. Subsequently, under each of the universities, users' community was stratified into students, research scholars, and faculty members. Under each stratum, the sample selected on a random basis. The users met personally to collect relevant data, while they came to the library and went on to search OPAC. A structured schedule, prepared for the purpose, was presented before library users and consequently, interviews and interpretations recorded systematically. In this manner, several factors have identified concerning subject searching and retrieval performance for Bengali documents. This study explores the access using subject headings in multilingual information retrieval systems. Moreover, the suitability of subject headings for retrieval of Bengali resources has ascertained from the users' point of view. The findings demand standard principles and rules for the construction of Bengali subject headings to maintain uniformity and consistency.

• 한국해양공학회지
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• 제33권3호
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• pp.236-244
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• 2019

Internal waves occur at the interface between two layers caused by a seawater density difference. The internal waves generated by a body moving in a two-layer fluid are also related to the generation of surface waves because of their interaction. In these complex flow phenomena, the experimental measurements and experimental set-up for the wave patterns of the internal waves and surface waves are very difficult to perform in a laboratory. Therefore, studies have mainly been carried out using numerical analysis. However, model tests are needed to evaluate the accuracy of numerical models. In this study, the various experimental conditions were evaluated using CFD simulations before experiments to measure the wave patterns of the internal waves and surface waves in a stratified two-layer fluid. The numerical simulation conditions included variations in the densities of the fluids, depth of the two-layer fluid, and moving speed of the underwater body.

• 한국의류학회지
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• 제25권6호
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• pp.1069-1078
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• 2001

Pattern grading is a technique used to increase or decrease the size of a garment pattern according to the measurements in a given size chart. The original pattern is graded and laid out for cutting before mass production. This study tried to classify body types for pattern grading of jacket by applying a concept of "drop"defined as the difference between chest girth and waist girth and the difference between hip girth and waist girth for pants. Data were collected through the stratified sampling method. 138 subjects were selected out of 1,290 subjects of our sample population. Findings were as follows : 1) For pattern grading of jacket, the cell with the chest girth of 96cm and the waist girth of 87cm had the highest frequency rate and body type was 87H type and the coverage of this type was 9.52%. Then, the size specification 87-96 was the center of distribution. H type had seven ones such as 72H, 75H, 78H, 81H, 84H. 87H and 90H. H type had 33 observations and frequency ratio of 26.19%. Same types could be graded up and down from the reference size for the age group. And this reference size became to the starting point for developing the grading system. 2) For pattern grading of pants, fatty types, H10 type had six ones such as 80H10. 82H10, 84H10, 86H10, 88H10 and 90H10. H10 type had 28 observations and frequency ratio of 20.29%. H6 type had 6 ones such as 84H6, 86H6, 88H6, 90H6. 92H6 and 94H6. H6 type had 27 observations and frequency ratio of 19.57%. If lower body types were classified as same ones, these types could be graded up and down proportionately.

• Nutrition Research and Practice
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• 제9권3호
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• pp.313-318
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• 2015

BACKGROUND/OBJECTIVES: Dietary pattern and its association with cardio-cerebrovascular disease have not been studied in Baoji city by now. This study was aimed to identify the dietary patterns among Chinese adults in Baoji, and explore the association between these dietary patterns and cardio-cerebrovascular disease. SUBJECTS/METHODS: A total of 4,968 participants were included in this study at 12 counties. With multistage stratified random sampling and semi quantitative food frequency questionnaire, the prevalence of cardio-cerebrovascular disease and dietary intake were investigated in 2013. We used factor analysis to establish dietary patterns. RESULTS: A total of 4,968 participants over 15 years old were included in this study. Five dietary patterns were identified in Baoji: protein, balanced, beans, prudent, and traditional patterns. The protein dietary pattern mainly included animal and plant proteins and was negatively associated with hypertension as well as stroke. The balanced pattern included carbohydrates, protein, and fat and was negatively associated with hypertension as well as stroke. The beans pattern was mainly beans and beans products and was negatively associated with hypertension. The prudent pattern only included staple foods and pickled vegetables and was positively associated with hypertension as well as coronary heart disease. The traditional pattern was representative of local Baoji traditional recipes and was positively associated with hypertension. CONCLUSIONS: The protein, balanced, and beans dietary patterns showed many protective effects on cardio-cerebrovascular disease. Based on these results, Baoji city residents should be encouraged to choose protein, balanced, and beans dietary patterns and abandon prudent and traditional patterns to prevent incidence of hypertension, coronary heart disease, and stroke.

• 한국조경학회지
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• 제23권2호
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• pp.124-136
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• 1995

This study was conducted to find the distinguished pattern of Korean 'Dae'. Therefore, the purpose of this study is to define how the pattern of 'Dae' has been developed and what is the characteristics of the pattern of Korean 'Dae'. The summarized results are as follows; 1. The types of 'Dae'(rock in the nature, a 'Dae' built artificially, a structure) were identified in the era of the three kingdoms. And in the era of the three kingdoms, 'Dae' was regarded as: a mysterious place related with a king, the place where concrete activities of a specific person had occurred in there, and a mountain peak 2. in the era of Koryo , artificial aspect of 'Dae' were emphasized. In addition, the activities occurred in the 'Dae' took concrete shape by kings. 3. The characteristics of the pattern of 'Dae' during Chosen Dynasty are: 1) A type of huge flat rock(27.6%), a type of mounts고 peak and a type of cuff(24.1%), a type of fantastic rock(15.5%), a type of stratified rock(6.9%) were shown 2) The main activities on 'Dae' were play , observation, and rest 3) In the viewpoint of the locational characteristics, 'Dae' were found in the mountains, at the top of the mountain peaks, on high hill, on cliffs, at the riversides, and on the beaches, etc. 4. With consideration on change trend of the number of'Dae' according to literature(time) , the biggest geographical distributions of 'Dae' were shows in Hamkyungdo in noddle of 15th century (Saejongsillockjiriji), in Kangwondo in the middle of 16th century (Sinjeongdonggukyecjiseongram), in Chunrado in middle of 17th century(Donggukyeojiji), and in Kyungsangdo in middle of 18th 19th century(Yeojidoseo, Eubji) 5. Through the whole period of Chosen Dynasty, the geographical distribution of 'Dae' had much in Kyungsangdo and Pyungahndo.

• 한국조경학회지
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• 제34권2호
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• pp.26-35
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• 2006

The purpose of this research is to suggest the planting methods and the reasonable target levels of IGS for promoting green streetscape in Seoul. Using the three dimensional computer simulations, various greening methods were applied to evaluate effectiveness of promoting green streetscape. The results of this study suggest that promoting tree planting on car lane is more effective than on pedestrian side walks. In wide streets, the height of tree has positive effects on promoting green streetscape. In both car lane and pedestrian side walks, the greening effects of tree planting both in zig-zag pattern and in parallel pattern were similarly most high. The width of strip in side strip planting has positive effect on promoting green streetscape. Promoting stratified planting is very effective. Promoting greening wall on pedestrian side walks is more effective than on car lane. Combined the results of IGS survey with the public officials and complex simulations, suggest that the optimal levels of IGS is ranging from 12.0% in alleys to 54.0% in car lanes among arterial roads.

• The Korean Journal of Ecology
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• 제8권2호
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• pp.61-68
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• 1985

The modeling of interception and absorption of light was studied in plant canopies at Mt. Kwanak. Followering results were obtained. Light intensity passing through the stacked leaves is attenuated exponentially. This phenomenon seems to be more clearly applied to the plant canopies, if they have large cumulative leaf area and are matured densely. Light interception and absorption are influenced by leaf thickness, shape pigments, and leaf area, and they have great effect on the maturation of canopies. It was confirmed that the light penetrating through the stratified canopies is decreased exponentially in dual pattern. The cumulative leaf area of a definite space in a certain plant canopy is the same as the growth of leaf area of the canopy at that time. A hypothetical model for calculating the light absorption in plant canopies, was established on the bases of phenomena that incident light is captured at the maximum level and light inerception effect is minimized by leaves.

• Journal of electromagnetic engineering and science
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• 제5권1호
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• pp.43-47
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• 2005

Microwave or optical photonic band-gap(PBG) structures are conventionally realized by cascading distributive elements in a periodic pattern. However, the frequency bandwidth obtained through such plainly periodic arrangement is typically narrow, corporate with a relatively high rejection side-lobe band. To alleviate such problems, a design involving a chirping and tapering technique is hence introduced and employed. The design has been applied in both a planar stratified dielectric medium as well as a strip-line transmission line structure, and results are validated when compared with the corresponding conventional PBG structure.

• 대한기계학회논문집B
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• 제33권9호
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• pp.722-727
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• 2009

The effect of the intake flow on the spray structure of a high pressure 11-hole fuel injector were examined in a single cylinder optical direct injection spark ignition (DISI) engine. The effects of injection timing and in-cylinder charge motion were investigated using the 2-dimensional Mie scattering technique. It was confirmed that in the homogeneous charge mode, the in-cylinder swirl charge motion played a major role in the fuel spray distribution during the induction stroke rather than the tumble flow. But, in the stratified charge mode, the effect of the in-cylinder charge was not so large that the injected spray pattern was nearly maintained and the increase of in-cylinder pressure by the upward moving piston reduced the fuel spray penetration.