• Title/Summary/Keyword: speed change

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The Study of Visual Fatigue by Monitor Letter Contrast with an Eye Tracker (아이트래커를 이용한 모니터 글자 대비도에 따른 눈의 피로도 연구)

  • Kim, Ha-Rim;Jeong, Ju-Hyun
    • Journal of Korean Ophthalmic Optics Society
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    • v.19 no.4
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    • pp.533-538
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    • 2014
  • Purpose: This study is to investigate correlation between eye fatigue and letter contrast according to letter contrast changes on monitor display. Methods: Reading speed test were carried out for 53 subjects (mean age: $22.68{\pm}1.85$ years) who have over Best-corrected visual acuity (BCVA) 1.0, and 45 subjects, who could read over 123 out of 163 letters among 53 subjects were selected. They were asked to read the letters which were composed of Black (contrast 100%), Dark gray (contrast 80%), Gray (contrast 80%), Light gray (contrast 30%) randomly. The change of their eye fatigue by letter contrast on monitor display was measured by monitoring their eyes with an eye-tracker while they were reading letters. Results: Event Duration (sec) was 33.635 for Black, 32.266 Dark gray, 33.936 for Gray, and 34.848 for Light gray. Average of Fixation Duration (sec) was 0.224 for Black, 0.218 for Dark gray, 0.239 for Gray and 0.243 for Light gray. Average of Pupil diameter (mm) was 41.133 mm for Black, 41.160 mm for Dark gray, 40.880 mm for Gray and 40.459 mm for Light gray. Frequency (blinks/sec) was 0.211 for Black, 0.206 for Dark gray, 0.221 for Gray, and 0.238 for Light gray. Conclusions: Event Duration and average of Fixation Duration were the shortest for Dark gray and the longest for Light gray. In average Pupil diameter was the biggest Dark gray and the smallest for Light gray. Blink Frequency (blinks/sec) was the lowest for Dark gray and the highest for Light gray. Visual fatigue by brightness of letters on monitor display was the least for Dark gray followed by Black, Gray and Light gray.

Analysis of Surface Sound Channel by Low Salinity Water and Its Mid-frequency Acoustic Characteristics in the East China Sea and the Gulf of Guinea (동중국해와 기니만에서 저염분수로 인한 표층음파채널과 중주파수 음향 특성 분석)

  • Kim, Hansoo;Kim, Juho;Paeng, Dong-Guk
    • The Journal of the Acoustical Society of Korea
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    • v.34 no.1
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    • pp.1-11
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    • 2015
  • Salinity affects sound speed in the low salinity environment, in the seas where freshwater from large rivers and flows into the marginal sea area near the Yangtze River and the Niger River. In this paper, SSC (Surface Sound Channel) formed by low salinity water was investigated in the East China Sea and the Gulf of Guinea of rainy season. The data from KODC (Korea Oceanographic Data Center) in the East China Sea and from ARGO (Array for Real-time Geostrophic Oceanography) in the Gulf of Guinea of the tropical area were used for analysis. SSC haline channel was formed 14 times among 32 SSC occurrences when the 90 data from 9 points were analyzed during a decade (2000 ~ 2009) in the East China Sea. In the Gulf of Guinea, haline channel was formed 18 times among 20 SSC occurrences during 3 years (2006 ~ 2009). When the sound speed gradient was analyzed from temperature-salinity gradient diagram, the gradients of both salinity and temperature affect SSC formation in the East China Sea. In contrast, the salinity gradient mostly affects SSC formation due to the least change of temperature in the well-developed mixed layer in the Gulf of Guinea. Their acoustic characteristics show that channel depth is 6.5 m, critical angle is $1.5^{\circ}$ and difference of transmission loss between surface and thermocline is 11.5 dB in the East China Sea, while channel depth is 18 ~ 24 m, critical angle is $4.0{\sim}5.4^{\circ}$ and difference of transmission loss is 21.5 ~ 27.9 dB in the Gulf of Guinea. These results are expected to be used as a basic understanding of the acoustic transmission changes due to low salinity water at the estuaries and the ocean with heavy precipitation.

Influences of Unilateral Mandibular Block Anesthesia on Motor Speech Abilities (편측 하악전달마취가 운동구어능력에 미치는 영향)

  • Yang, Seung-Jae;Seo, In-Hyo;Kim, Mee-Eun;Kim, Ki-Suk
    • Journal of Oral Medicine and Pain
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    • v.31 no.1
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    • pp.59-67
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    • 2006
  • There exist patients complaining speech problem due to dysesthesia or anesthesia following dental surgical procedure accompanied by local anesthesia in clinical setting. However, it is not clear whether sensory problems in orofacial region may have an influence on motor speech abilities. The purpose of this study was to investigate whether transitory sensory impairment of mandibular nerve by local anesthesia may influence on the motor speech abilities and thus to evaluate possibility of distorted motor speech abilities due to dysesthesia of mandibular nerve. The subjects in this study consisted of 7 men and 3 women, whose right inferior alveolar nerve, lingual nerve and long buccal nerve was anesthetized by 1.8 mL lidocaine containing 1:100,000 epinephrine. All the subjects were instructed to self estimate degree of anesthesia on the affected region and speech discomfort with VAS before anesthesia, 30 seconds, 30, 60, 90, 120 and 150 minutes after anesthesia. In order to evaluate speech problems objectively, the words and sentences suggested to be read for testing speech speed, diadochokinetic rate, intonation, tremor and articulation were recorded according to the time and evaluated using a Computerized Speech $Lab^{(R)}$. Articulation was evaluated by a speech language clinician. The results of this study indicated that subjective discomfort of speech and depth of anesthesia was increased with time until 60 minutes after anesthesia and then decreased. Degree of subjective speech discomfort was correlated with depth of anesthesia self estimated by each subject. On the while, there was no significant difference in objective assessment item including speech speed, diadochokinetic rate, intonation and tremor. There was no change in articulation related with anesthesia. Based on the results of this study, it is not thought that sensory impairment of unilateral mandibular nerve deteriorates motor speech abilities in spite of individual's complaint of speech discomfort.

Verification of Kompsat-5 Sigma Naught Equation (다목적실용위성 5호 후방산란계수 방정식 검증)

  • Yang, Dochul;Jeong, Horyung
    • Korean Journal of Remote Sensing
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    • v.34 no.6_3
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    • pp.1457-1468
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    • 2018
  • The sigma naught (${\sigma}^0$) equation is essential to calculate geo-physical properties from Synthetic Aperture Radar (SAR) images for the applications such as ground target identification,surface classification, sea wind speed calculation, and soil moisture estimation. In this paper, we are suggesting new Kompsat-5 (K5) Radar Cross Section (RCS) and ${\sigma}^0$ equations reflecting the final SAR processor update and absolute radiometric calibration in order to increase the application of K5 SAR images. Firstly, we analyzed the accuracy of the K5 RCS equation by using trihedral corner reflectors installed in the Kompsat calibration site in Mongolia. The average difference between the calculated values using RCS equation and the measured values with K5 SAR processor was about $0.2dBm^2$ for Spotlight and Stripmap imaging modes. In addition, the verification of the K5 ${\sigma}^0$ equation was carried out using the TerraSAR-X (TSX) and Sentinel-1A (S-1A) SAR images over Amazon rainforest, where the backscattering characteristics are not significantly affected by the seasonal change. The calculated ${\sigma}^0$ difference between K5 and TSX/S-1A was less than 0.6 dB. Considering the K5 absolute radiometric accuracy requirement, which is 2.0 dB ($1{\sigma}$), the average difference of $0.2dBm^2$ for RCS equation and the maximum difference of 0.6 dB for ${\sigma}^0$ equation show that the accuracies of the suggested equations are relatively high. In the future, the validity of the suggested RCS and ${\sigma}^0$ equations is expected to be verified through the application such as sea wind speed calculation, where quantitative analysis is possible.

Effectiveness Analysis of HOT Lane and Application Scheme for Korean Environment (HOT차로 운영에 대한 효과분석 및 국내활용방안)

  • Choi, Kee Choo;Kim, Jin Howan;Oh, Seung Hwoon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1D
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    • pp.25-32
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    • 2009
  • Currently, various types of TDM (Transportation Demand Management) policies are being studied and implemented in an attempt to overcome the limitations of supply oriented policies. In this context, this paper addressed issues of effectiveness and possible domestic implementation of the HOT lane. The possible site of implementation selected for this simulation study is part of the Kyung-bu freeway, where a dedicated bus lane is currently being operated. Minimum length of distance required in between interchanges and access points of the HOT lane for vehicles to safely enter and exit the lane, and traffic management policies for effectively managing the weaving traffic trying to enter and exit the HOT lane were presented. A 5.2km section of freeway from Ki-heuing IC to Suwon IC and a 8.3km section from Hak-uei JC to Pan-gyo JC have been selected as possible sites of implementation for the HOT lane, in which congestion occurs regularly due to the high level of travel demand. VISSIM simulation program has been used to analyze the effects of the HOT lane under the assumption that one-lane HOT lane has been put into operation in these sections and that the lane change rate were in between 5% to 30%. The results of each possible scenario have proven that overall travel speed on the general lanes have increased as well by 1.57~2.62km/h after the implementation of the HOT lane. It is meaningful that this study could serve as a basic reference data for possible follow-up studies on the HOT lane as one effective method of TDM policies. Considering that the bus travel rate would continue increase and assuming the improvement in travel speed on general lanes, similar case study can be implemented where gaps between buses on bus lane are available, as a possible alternative of efficient bus lane management policies.

Evaluation of frictional forces between orthodontic brackets and archwires (교정용 브라켓과 교정선 사이의 마찰력)

  • Jeong, Tae-Jong;Choie, Mok-Kyun
    • The korean journal of orthodontics
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    • v.30 no.5 s.82
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    • pp.613-623
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    • 2000
  • The purpose of this study was to amount of the frictional forces with the brackets and wires, ligation methods, dry/wet, offsets, interbracket distances, velocity and to compare them each other by different conditions. This study tested 0.018'x0.025' slot sized 8 types of orthodontic bracket systems and 0.016', 0.016'x0.022' sized stainless steel, NiTi, Cu-NiTi orthodontic wires. One cuspid bracket were positioned on the slide glass and archwire was engaged into bracket and ligated with elastomeric modules. The values of frictional forces were measured with the instron universal testing machine. The results were as follows; 1. Polycrystalline ceramic bracket had the highest mean frictional forces and followed and by ceramic reinforced plastic bracket, metal bracket, plastic bracket with metal slot, monocrystalline ceramic bracket, single bracket, self-ligating bracket, friction free bracket in descending order. The self-ligating bracket showed low frictional forces in the round wires and high frictional forces in the rectangular wires. 2. Stainless steel wires had the least frictional forces and followed by NiTi, Cu-NiTi wires in descending order. Round wires had lower frictional forces then that of rectangular wires. 3. The stainless steel ligation method had significantly greater mean frictional forces them the elastomeric module ligation method. 4. Artificial saliva statistically increased the frictional forces in stainless steel wire, NiTi wire and Cu-NiTi wire. 5. There was a statistically significant difference with offset change 6. There was no statistically significant difference with interbracket distance in stainless steel wires but a significant difference in NiTi wires as the interbracket was decreased. 7 There was no statistically significant difference with velocity change. From the above findings, self-ligating bracket, stainless steel wires and the elastomeric module ligation method might be effective than any other materials to reduce the frictional forces in the orthodontic treatment and can be correlated to clinical situations seen in orthodontic patient care.

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Study on the Midwater Trawl Available in the Korean Waters ( V ) - Opening Efficiency of the Otter Board with a Large Float on the Top - (한국 근해에 있어서의 중층 트로올의 연구 ( V ) - 전개판에 대형 뜸을 달았을 때의 전개성능 -)

  • Lee, Byong-Gee;Kim, Min-Suk
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.24 no.2
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    • pp.78-82
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    • 1988
  • Near sea trawlers of Korea sometimes catch pelagic fishes like file fish by using midwater trawl gear even though usually catch bottom fish. It is reasonable to use the specific otter board as well as specific net in bottom trawling and in midwater trawling respectively. But, the trawlers are so small ranging 100 to 120GT, 700 to 100ps that it is very complicated to use different otter board for bottom trawling and for midwater trawling. The otter board for bottom trawling. is also used for the midwater trawling without any change even though the net is changed into the specific one. Although the otter board in the midwater trawling should be lighter than that for bottom trawling, to use otter board for bottom trawling directly for the midwater trawling without any change makes the net easily touch the sea bed and also make the horizontal opening of the otter boards be limited owing to the length of warp in the southern sea of Korea, main fishing ground of midwater trawling, which is 100m or so in depth. That is why the otter board for the midwater trawling should be made lighter than that in the bottom trawling, even if temporary. The authors carried out an experiment to achieve this purpose by attaching a large styropol float on the top of the otter board. In this experiment, underwater weight of the otter board was 630kg and buoyancy of the float was 510kg. To determine the depth and horizontal opening of the otter board, two fish finder was used. A transmitter of 50KHz fish finder was set downward through the shoe plate of otter board to determine the elevation of otter board from the sea bed, and a transmitter of 200KHz fish finder was set sideways on the starboard otter board to be able to detect the distance between otter boards. The obtained results can be summarized as follows: 1. The actual towing speed in the experiment varied 1.1 to 1.8 m/sec. 2. The depth of otter board was within 41 to 25m with float on the top and 45 to 26m without float in case of the warp length 100m, whereas the depth 68-44m with float and 74-46m without float in case of the warp length 150m. This fact means that the depth with float was 9-4% shallower than that without float. 3. The horizontal opening between otter boards was within 34-41m with float and 30-38m without float in case of the warp length 100m, whereas the opening was 44-50m with float and 37-46m without float in case of the warp length 150m. This fact means the opening with float was 10% greater than that without float in case of the warp length 100m, and 15% greater in case of the warp length 150m. 4. The horizontal opening between wing tips by using the otter board with float was 1m greater than by without float in case of the warp length 100m, whereas the opening by with float was 2m greater than by without float in case of warp length 150m. From this fact, it can be estimated that the effective opening area of the net mouth by using the otter board with float could be made 10% greater than by without float in case of warp length 100m, whereas the area with float 20% greater than by without float in case of warp length 150m.

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Study on economic effects of outsourcing of food materials on the hotel kitchen - Focus on cooking Western food in the first class hotel - (식재료 아웃소싱이 경제적 주방에 미치는 영향에 관한 연구 - 특1급호텔 양식조리를 중심으로 -)

  • 성태종
    • Journal of Applied Tourism Food and Beverage Management and Research
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    • v.13 no.2
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    • pp.45-69
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    • 2002
  • This study is designed to examine feasibility and limitation of outsourcing in cooking Western food in a hotel, to interpret importance of outsourcing(eg. outside order, outside procurement, outside supply) in a broad sense in order to reinforce the core capacity in the cooking department, and to know whether the cooking human power is efficiently used and how much the chefs recognize outsourcing of food materials. As many companies conduct restructuring to cut down its size, the reduction of human power led the Western food cooking in the hotel to lower core capacities, lower quality, and lower efficiency. In addition, the sagging morale of chefs undermined creativity. To change from the traditional kitchen to an economic kitchen needs to look into importance of outsourcing, cognitive attitude of chefs, relation with outside suppliers. Here suggests performance of positive changes in the structure The study examined feasibility and limitation of outsourcing in the hotel kitchen as well as chefs' cognitive attitude toward outsourcing of food materials to reinforce core capabilities of the hotel kitchen. 1. Companies of outsourcing are selected according to variability of price conditions, flexibility of contract conditions, popularity of the outsourcing company, and reputation of the outsourcing company. 2. The importance of outsourcing in the Western food cooking is divided into 4 factors such as standard of selecting outsourcing companies, policies of cooking manu, quality of cooking, and quantity of cooking. 3. The most feasible section in outsourcing of food materials is a process of kneading flour for bread, which shows that many Western-food chefs expect to put higher possibility of outsourcing on the kneading. In other words, when it comes to confectionery and bakery, there are many outside expert processing companies supplying high quality products. In the order of outsourcing feasibility, sauce is followed by processed vegetable, garnish of main dish, and soup. The least feasible section in outsourcing of food materials is appetize. Appetize includes a concept of a improvised dish and needs speed. Due to its color, freshness, and sensibility of taste, the appetize plays a key role in the Western food cooking. 4. When outsourcing is taken in place, the highest risk is to lower the inner cooking skills. Therefore chefs in charge of the Western food sequently recognize both internal problems including storage of cooking skills, unstability of layoffs, and loss of cooperation between departments, and external problems including inferior goods, difficulty of differentiating manu, delay of delivery, and expiration date. It shows that most of the Western food chefs consider risks of the internal problems at first. 5. A effective outsourcing needs appropriate selection of outsourcing companies, maintenance of credibility, active communication, check and management of hygiene. However regardless of their position or career, chefs in charge of the Western food have the same cognitive attitude toward selecting successful outsourcing companies after the outsourcing system is enforced. The core of cooking, or a final stage in the full process of so-called artistic cooking, should be treated with insourcing. Reduction of several cooking processes resulted in shortened cooking time, increased efficiency, faster cooking, cutting the waiting-lines, and finally more room for customers. The outsourcing system can reduce or eliminate the following processes in cooking: buying various food materials, checking, storing, preparing, and processing. Especially in the Western food cooking department of a hotel, the outsourcing system should be enforced to make an economic kitchen and to efficiently manage it. Wow it's time to change from the traditional kitchen to an economic kitchen in the hotel cooking department. For that, the cooking department should become a small but strong organization by outsourcing except its core work.

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A Way for Creating Human Bioclimatic Maps using Human Thermal Sensation (Comfort) and Applying the Maps to Urban and Landscape Planning and Design (인간 열환경 지수를 이용한 생기후지도 작성 및 도시·조경계획 및 디자인에의 적용방안)

  • Park, Soo-Kuk
    • Journal of the Korean Institute of Landscape Architecture
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    • v.41 no.1
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    • pp.21-33
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    • 2013
  • The purpose of this study is to find applicabilities of human bioclimatic maps, using human thermal sensation(comfort) in summer, with microclimatic in situ data and computer simulation results at the study site of downtown Daegu. This includes the central business district(CBD) area and two urban parks, the Debt Redemption Movement Memorial Park and the 2.28 Park, for urban and landscape planning and design. Climatic data and urban setting information for the analysis of human thermal sensation were obtained from in situ measurement and the geographic information system data. As a result, the CBD had higher air temperature than the parks when the wind speed was low. Relative humidities were opposite to the air temperature. Especially, same directional streets with local wind direction had lower air temperature than streets perpendicular to the wind direction. The most important climatic variable of human thermal sensation in summer was direct beam solar radiation. Also, creating shadow areas would be the most relevant method for modifying hot thermal environments in urban areas. The most effective method of creating shadow patterns was making a tree shadow over a pergola, and the second best one was making a tree shadow on the front of north directional building walls. Moreover, how to plant trees for creating shadow patterns was important as well as what kind of trees should be planted. The results of human thermal sensation were warm to very hot at sunny areas and neutral to warm at shaded ones. At the sunny areas, wide, squared shape areas had a little bit higher thermal sensation than those of narrow streets. The albedo change of building walls 0.15 and ground surface 0.1 could change 1/6 of a sensation level at the shaded areas and 1/3 at the sunny ones. These microclimatic approaches will be useful to find appropriate methods for modifying thermal environments in urban areas.

A Research on Perception of Leadership Affects Long-term Working Intention in the Beauty Service Employees (미용서비스종사자의 리더십 지각이 장기근속의도에 미치는 영향에 관한 연구)

  • Oh, Jin Sook;Youn, Chun Sung
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.7 no.4
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    • pp.21-32
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    • 2012
  • The current beauty service of Korea is upgrading its outside appearance from traditional small-shop image and its speed of change and competition are more severe than ever before. The top priority trait of beauty management is based on man-power resource, and personnel-management is the most important thing that more than anything else. Compared with other arenas of business, personnel management plays a key role in beauty industry. As a result, this research begins with the issue of personnel management. In addition, I will show that the management leadership of beauty service affects organization civil actions and changing jobs in the beauty industry employees, and the leadership can lower changing job rate to some extent. The role and duty of business manager is very significant because the dependence of man-power resource is magnificent in beauty service. In spite of rapid changing of economic surroundings, the management of beauty service is still working without any detail plans. It is no exaggeration to say that the most of beauty service managers are lack of leadership conception. Although the demands of customers are changing everyday, the frequent changing of jobs among talented employees drops customers credibility and high-quality service. From a management viewpoint, re-training cost of employees leads to economic loss and the company suffers from financial problems. As a result, it creates vicious circle in the beauty industry. Today, the management atmosphere in the beauty service is hard to get its right track because of the cutthroat competitions of beauty industry and difficulties of hiring promising employees. It has been said that "Nothing ventured, Nothing gained" Above all, the beauty service requires job speciality and it produces economic profits. Therefore, the managers desperately need to change the way they regard those with job changers. In this research shows the principal index of the leadership type of beauty business managers how much affects its employees' long-term working condition. The new concept of leadership, such as alternative suggestions, setting goals, and organization civil action will reorganize the stereo-type frame. I will also investigate the factors of job changing and intention of the beauty service employees for the development option of the beauty industry.

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