Loading [MathJax]/jax/output/CommonHTML/jax.js
  • Title/Summary/Keyword: Directional Information

Search Result 1,313, Processing Time 0.023 seconds

Development of Satellite and Terrestrial Convergence Technology for Internet Services on High-Speed Trains (Service Scenarios) (고속열차대상의 위성인터넷 서비스 제공을 위한 위성무선연동 기술(서비스 시나리오 관점))

  • Shin, Min-Su;Chang, Dae-Ig;Lee, Ho-Jin
    • Journal of Satellite, Information and Communications
    • /
    • v.2 no.2
    • /
    • pp.69-74
    • /
    • 2007
  • Recently, the demands for the satellite broadband mobile communication services are increased. To provide these services, mobile satellite communication systems for the passengers or crews on the high-speed moving vehicles, are being developed for the last several years especially in the Europe and North America. However, most of these systems can provide only several hundred kbps of transmission rate and this is not enough performance to provide satellite internet service for the group users such as passengers on the high-speed train. Moreover, service availability with these systems is limited to be rather low because they don't have any countermeasure scheme for the N-LOS environment which happens often along the railway. This paper describes mobile broadband satellite communication system, which is on the development, to provide high data-rate internet services to the high-speed trains. This system is applied with the inter-networking scenarios of both satellite/terrestrial network and satellite/gap-filler network so that it can provide seamless service even in the train operating environment, and these inter-networking schemes result in high service availability. And this system also has the countermeasure schemes, such as upper layer FEC and antenna diversity, for the short fading which is occurred periodically on the railway due to the power supplying structures so that it can provide high speed internet services. Mobile DVB-S2 technology which is now being standardized in the DVB is used for the forward-link transmission and DVB-RCS for the return-link.

  • PDF

The Design of Object-based 3D Audio Broadcasting System (객체기반 3차원 오디오 방송 시스템 설계)

  • 강경옥;장대영;서정일;정대권
    • The Journal of the Acoustical Society of Korea
    • /
    • v.22 no.7
    • /
    • pp.592-602
    • /
    • 2003
  • This paper aims to describe the basic structure of novel object-based 3D audio broadcasting system To overcome current uni-directional audio broadcasting services, the object-based 3D audio broadcasting system is designed for providing the ability to interact with important audio objects as well as realistic 3D effects based on the MPEG-4 standard. The system is composed of 6 sub-modules. The audio input module collects the background sound object, which is recored by 3D microphone, and audio objects, which are recorded by monaural microphone or extracted through source separation method. The sound scene authoring module edits the 3D information of audio objects such as acoustical characteristics, location, directivity and etc. It also defines the final sound scene with a 3D background sound, which is intended to be delievered to a receiving terminal by producer. The encoder module encodes scene descriptors and audio objects for effective transmission. The decoder module extracts scene descriptors and audio objects from decoding received bistreams. The sound scene composition module reconstructs the 3D sound scene with scene descriptors and audio objects. The 3D sound renderer module maximizes the 3D sound effects through adapting the final sound to the listner's acoustical environments. It also receives the user's controls on audio objects and sends them to the scene composition module for changing the sound scene.

A Study on the Relation Exchange Rate Volatility to Trading Volume of Container in Korea (환율변동성과 컨테이너물동량과의 관계)

  • Choi, Bong-Ho
    • Journal of Korea Port Economic Association
    • /
    • v.23 no.1
    • /
    • pp.1-18
    • /
    • 2007
  • The purpose of this study is to examine the effect of exchange rate volatility on Trading Volume of Container of Korea, and to induce policy implication in the contex of GARCH and regression model. In order to test whether time series data is stationary and the model is fitness or not, we put in operation unit root test, cointegration test. And we apply impulse response functions and variance decomposition to the structural model to estimate dynamic short run behavior of variables. The major empirical results of the study show that the increase in exchange rate volatility exerts a significant negative effect on Trading Volume of Container in long run. The results Granger causality based on an error correction model indicate that uni-directional causality between trading volume of container and exchange rate volatility is detected. This study applies impulse response function and variance decompositions to get additional information regarding the Trading Volume of Container to shocks in exchange rate volatility. The results indicate that the impact of exchange rate volatility on Trading Volume of Container is negative and converges on a stable negative equilibrium in short-run. Th exchange rate volatility have a large impact on variance of Trading Volume of Container, the effect of exchange rate volatility is small in very short run but become larger with time. We can infer policy suggestion as follows; we must make a stable policy of exchange rate to get more Trading Volume of Container

  • PDF

Development of Multi-agent Based Deadlock-Free AGV Simulator for Material Handling System (자재 취급 시스템을 위한 다중 에이전트 기반의 교착상태에 자유로운 AGV 시뮬레이터 개발)

  • Lee, Jae-Yong;Seo, Yoon-Ho
    • Journal of the Korea Society for Simulation
    • /
    • v.17 no.2
    • /
    • pp.91-103
    • /
    • 2008
  • In order to simulate the behavior of automated manufacturing systems, the performance of material handling systems should be measured dynamically. Multi-Agent technology could be well adapted for the development of simulator for distributed and intelligent manufacture systems. A multi-agent system is composed of one coordination agent and multiple application agents. Issues in AGVS simulator can be classified by the set-up and operating problems. Decisions on the number of vehicles, bi- or uni-directional guide-path, etc. are fallen into the set-up problem category, while deadlock tree algorithm and conflict resolution are in operating problem. In this paper, a multi-agent based deadlock-free simulator for automated guided vehicle system(AGVS) are proposed through the use of multi-agent technologies and the development of deadlock-free algorithm. In this AGVS simulator proposed, well-known Floyd algorithm is used to create AGVS Guide path, through which AGVS move. Also, AGVs avoid vehicle conflict and deadlock using check path algorithm. And Moving vehicle agents are operated in real-time control by coordination agent. AGV position is dynamically calculated based on the concept of rolling time horizon. Simulator receives and presents operating information of vehicle in AGVS Gaunt chart. The performance of the proposed algorithm and developed simulator based on multi-agent are validated through set of experiments.

  • PDF

Energy-Efficient Data-Aware Routing Protocol for Wireless Sensor Networks (무선 센서 네트워크를 위한 에너지 효율적인 데이터 인지 라우팅 프로토콜)

  • Lee, Sung-Hyup;Kum, Dong-Won;Lee, Kang-Won;Cho, You-Ze
    • Journal of the Institute of Electronics Engineers of Korea CI
    • /
    • v.45 no.6
    • /
    • pp.122-130
    • /
    • 2008
  • In many applications of wireless sensor networks, sensed data can be classified either normal or urgent data according to its time criticalness. Normal data such as periodic monitoring is loss and delay tolerant, but urgent data such as fire alarm is time critical and should be transferred to a sink with reliable. In this paper, by exploiting these data characteristics, we propose a novel energy-efficient data-aware routing protocol for wireless sensor networks, which provides a high reliability for urgent data and energy efficiency for normal data. In the proposed scheme, in order to enhance network survivability and reliability for urgent data, each sensor node forwards only urgent data when its residual battery level is below than a threshold. Also, the proposed scheme uses different data delivery mechanisms depending on the data type. The normal data is delivered to the sink using a single-path-based data forwarding mechanism to improve the energy-efficiency. Meanwhile, the urgent data is transmitted to the sink using a directional flooding mechanism to guarantee high reliability. Simulation results demonstrate that the proposed scheme could significantly improve the network lifetime, along with high reliability for urgent data delivery.

A STUDY ON THE CHANGES IN PATIENT DISTRIBUTION AND PRACTICE PATTERN FOR LAST 8 YEARS IN THE DEPARTMENT OF PEDIATRIC DENTISTRY OF CHONNAM NATIONAL UNIVERSITY DENTAL HOSPITAL (최근 8년간 전남대학교 치과병원 소아치과에 내원한 초진환자의 분포 및 진료현황에 관한 실태조사(2003-2010))

  • Son, Jeong-Min;Kim, Seon-Mi;Choi, Nam-Ki
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.39 no.4
    • /
    • pp.373-382
    • /
    • 2012
  • The purpose of this study was to understand the change of demands in young patients and to suggest a directional shift for the pediatric dental practitioners who are facing these changes. This study collected data on new patients who had visited Chonnam National University Dental Hospital, Department of Pediatric Dentistry from 2003 to 2010 and the researchers were able to find out the following information. Total number of dental visits has been increasing since 2009 and 2010, which includes an increase of male patients in the 13~15 years age group showed significant increase and that in the 3~4 years age group showed a significant decrease. December showed the largest number of total dental visits, of which 69.6% of newly visit patients were living in Gwang-ju. Patients who had systemic diseases were 10.7% of total newly visit patients and 19.1% of patients received sedative treatment. Considering the chief complaints of new patients, 36% of patients visited because of dental caries. Regarding the dental treatment of patients, 38.4% had restoration treatment in 2003 and 30.4% had restoration treatment in 2010.

Signatures Verification by Using Nonlinear Quantization Histogram Based on Polar Coordinate of Multidimensional Adjacent Pixel Intensity Difference (다차원 인접화소 간 명암차의 극좌표 기반 비선형 양자화 히스토그램에 의한 서명인식)

  • Cho, Yong-Hyun
    • Journal of the Korean Institute of Intelligent Systems
    • /
    • v.26 no.5
    • /
    • pp.375-382
    • /
    • 2016
  • In this paper, we presents a signatures verification by using the nonlinear quantization histogram of polar coordinate based on multi-dimensional adjacent pixel intensity difference. The multi-dimensional adjacent pixel intensity difference is calculated from an intensity difference between a pair of pixels in a horizontal, vertical, diagonal, and opposite diagonal directions centering around the reference pixel. The polar coordinate is converted from the rectangular coordinate by making a pair of horizontal and vertical difference, and diagonal and opposite diagonal difference, respectively. The nonlinear quantization histogram is also calculated from nonuniformly quantizing the polar coordinate value by using the Lloyd algorithm, which is the recursive method. The polar coordinate histogram of 4-directional intensity difference is applied not only for more considering the corelation between pixels but also for reducing the calculation load by decreasing the number of histogram. The nonlinear quantization is also applied not only to still more reflect an attribute of intensity variations between pixels but also to obtain the low level histogram. The proposed method has been applied to verified 90(3 persons * 30 signatures/person) images of 256*256 pixels based on a matching measures of city-block, Euclidean, ordinal value, and normalized cross-correlation coefficient. The experimental results show that the proposed method has a superior to the linear quantization histogram, and Euclidean distance is also the optimal matching measure.

Construction of the Smoke Exhaust System and Its Applicability by the Fire Model Test for a Bidirectional Tunnel (대면교행터널에서 배연시스템의 구축과 화재모형실험에 의한 적정성 평가)

  • Lee Sang-Eun;Lee Chang-Woo
    • Tunnel and Underground Space
    • /
    • v.15 no.6 s.59
    • /
    • pp.452-461
    • /
    • 2005
  • In a bidirectional tunnel, the accident rate is 1.5 times as high as that of one directional tunnel , the risk of a fire is increased. On fire, there is a problem that the jet fan should not be operated until completion of refuge. To be special, as the great damages occur owing to the expansion of smoke in long tunnels, there is a need to minimize fatality by constructing cross passage and smoke removal system. This study aims at verifying the efficiency of smoke exhaust system through fire propagation simulation as well as scale model test. The results show that completion of escape through emergency exit requires 335 seconds, while addition of smoke exhaust system reduce the escape time to 185 seconds. Also, near the fire source temperature decreased by about 60C. Without the exhaust system, fire propagation speed was in the range of 0.36 and 0.82 m/s, and it dropped to 0.27\~0.58m/s with the exhaust system on. Taking into account the escape speed of tunnel users, usually 0.7\~1.0m/s, the emergency exit built every 150m is sufficient for the safe egress. The ultimate goal of this study is to provide fundamental information for the smoke exhaust system in bidirectional tunnels.

The Line Feature Extraction for Automatic Cartography Using High Frequency Filters in Remote Sensing : A Case Study of Chinju City (위성영상의 형태추출을 통한 지도화 : 고빈도 공간필터 사용을 중심으로)

  • Jung, In-Chul
    • Journal of the Korean association of regional geographers
    • /
    • v.2 no.2
    • /
    • pp.183-196
    • /
    • 1996
  • The purpose of this paper is to explore the possibility of automatic extraction of line feature from Satellite image. The first part reviews the relationship between spatial filtering and cartographic interpretation. The second part describes the principal operations of high frequency filters and their properties, the third part presents the result of filtering application to the SPOT Panchromatic image of the Chinju city. Some experimental results are given here indicating the high feasibility of the filtering technique. The results of the paper is summarized as follows: Firstly the good all-purposes filter dose not exist. Certain laplacian filter and Frei-chen filter were very sensitive to the noise and could not detect line features in our case. Secondly, summary filters and some other filters do an excellent job of identifying edges around urban objects. With the filtered image added to the original image, the interpretation is more easy. Thirdly, Compass gradient masks may be used to perform two-dimensional, discrete differentiation directional edge enhancement, however, in our case, the line featuring was not satisfactory. In general, the wide masks detect the broad edges and narrow masks are used to detect the sharper discontinuities. But, in our case, the difference between the 3×3 and 7×7 kernel filters are not remarkable. It may be due to the good spatial resolution of Spot scene. The filtering effect depends on local circumstance. Band or kernel size selection must be also considered. For the skillful geographical interpretation, we need to take account the more subtle qualitative information.

  • PDF

A Study on the Preventive Education for Adolescents′s Problems in Home Economic Education (II) - Adolescents′Culture Analyzed with Newspaper Articles Concerning Adolescents - (가정과 교육에서의 청소년문제 예방교육을 위한 기초 연구 (II) -청소년관련 신문기사분석을 통해 본 청소년 문화 -)

  • 배영미
    • Journal of Korean Home Economics Education Association
    • /
    • v.10 no.2
    • /
    • pp.131-144
    • /
    • 1998
  • The lack of characteristical understanding of the Home Economics Education will have difficulty in achieving the goal of the Home Economics Education. To allow the Home Economics Education class in school contribute toward the enhancement of the quality of life, it is inevitable to reinforce the recognition of the importance and necessity of the Home Economics Education and to newly propose a directional guidance forward the coming 21st century. The purpose of this study was to provide basic data for planners of the future Home Economics Education by surveying research administrators in charge of programming the overall school curriculum. This study was conducted under the following procedure to have the outcome as follows ; 1. Answers from respondents of age over 50 or careers over 16 years tended to grasp the goal of Home Economics Education in relation to the enhancement of quality of life rather than to the accumulation of knowledge, skill or capacity. 2. Of all the surveyed, 9.64% regarded Home Economics Education as an essential part of school education and the positive ratio was higher with younger respondents. 3. To the question asking if the high school Home Economics Education could have influence on one's capacity, 97.2% of the answerers said yes. The respondents with career under 15 year showed 100% of positive agreement in this matter and of age under 40 marked much higher ratio of 98.84% than the elders. 4. The overall recognition of the necessity for separate sections in Home Economics Education programmed in accordance with the 6th Revision of High School Curriculum displayed a considerably high ratio, with a little differences among age and job groups. The purpose of this study is to analyze and understand adolescents'culture, thereby to provide fundamental information for Preventive Education for Adolescents'Problems in Home Economic Education. 745 articles collected in computer communication service were used for the analysis. The data were analyzed by frequency and percentage using the SPSS/PC+computer program. The most important results of this study were as follows ; 1) Concerning 'Adolescent's Problems's, problems such as violence, homicide and robbery were treated with the greatest frequency. It was also analyzed that the older generations are highly inclined to understand adolescents'culture as a negative one, for example, 'delinquency'or 'immaturity'. 2) Although the area of 'Adolescents'Education'was treated most frequently reflecting the high educational concern in our society, the significant part of those articles were on wrongful educational administration. As much as 70.6% of the articles analyzed were on 'Education'and 'Problems'. Thereby it may be concluded that the other areas such as health, activities, worries, values and harmful environments ere treated respectively as only a 'subculture'or'fragmentary culture'. The articles containing correlations and interactions among them and certain alternative proposals were very rare. 3) The areas such as 'Worries and Counselling'and 'Health'were occupying only a small portion of the articles. The articles which were treating the practical worries and their resolutions were even rarer. 4) 'Values'of the adolescents tended to be viewed by the older generations very negatively. It was also found that the older generations gave the tendency to see the 'consumption culture'of the adolescents as a kind of 'counter culture'or'subculture'.

  • PDF