• Title/Summary/Keyword: Guard Time

Search Result 276, Processing Time 0.032 seconds

An OFDM Receiver Scheme for Multipath Environment with Delay Profile over the Guard Interval (가드인터벌을 초월하는 지연프로필의 멀티패스채널에 적합한 OFDM수신시스템)

  • 주창복
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.4 no.4
    • /
    • pp.66-72
    • /
    • 2003
  • In the present paper some fundamentals about exceeding the guard interval of an OFDM system is going to discuss and will introduce method to cancel a ISI and ICI effects. In this paper, the performance characteristics of robust OFDM receiving system algorithm that is composed of a channel estimator using recursive least square(RLS) algorithm in time domain and of a ISI and ICI replica and subtracter using the channel coefficients are presented. By computer simulation method, the effect of suppression of ISI and ICI is demonstrated and compared the BER performance with a conventional 1-tap equalized system. Especially the presented scheme improves the BER performance at low SNRs more or so compared with the conventional one-tap equalized receiving configuration.

  • PDF

Effect of Claw Abrasives in Cages on Claw Condition, Feather Cover and Mortality of Laying Hens

  • Glatz, P.C.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.17 no.10
    • /
    • pp.1465-1471
    • /
    • 2004
  • A trial was conducted to determine the effect of abrasive strips and abrasive paint in layer cages on claw length and claw sharpness, foot condition, feather cover and mortality of hens. During the preparation of the cages for the experiment it was simpler and took less time to apply the pre-prepared paint with a spatula to the egg guard compared to sticking the abrasive strips onto the egg guard. Fitting the strips took longer because it had to be cut from a 25 mm roll, cut into the appropriate lengths, the tape backing removed and then stuck onto the egg guard section. Abrasive paint was more effective as a claw shortener than abrasive strips. The birds using the abrasive paint had the shortest (p<0.05) claw length and lowest (p<0.05) claw sharpness. One of the original reasons for reducing claw length with claw shorteners was to reduce mortality by minimising skin skin abrasions caused by the claws. Surprisingly hen mortality from prolapse and cannibalism was higher (p<0.05) in cages fitted with abrasives. There are no other reports in the literature showing an increase in prolapse and cannibalism from hens using abrasives.

Virtual-Channel Division Duplex via Dual Coding (이중 부호화를 이용한 가상 채널에서의 양방 통신 기법)

  • Ju, Hyung-Sik;Lee, Sung-Eun;Hong, Dae-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.45 no.1
    • /
    • pp.51-58
    • /
    • 2008
  • We propose a new duplex which does not require guard resources in MIMO environments. In the proposed duplex, two virtual channels in spatial domain are generated by preceding and postcoding MIMO channels, not to use guard resources in either the time or frequency domain. The capacity can be improved by properly selecting precoder and postcoder. We show the improved capacity of the proposed duplex outperforms conventional duplexes even without guard resources.

Effect Analysis of Timing Offsets for Asynchronous MC-CDMA Uplink Systems (비동기 MC-CDMA 상향 링크 시스템에서의 시간 옵셋 영향 분석)

  • Ko, Kyun-Byoung;Woo, Choong-Chae
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.47 no.8
    • /
    • pp.1-8
    • /
    • 2010
  • This paper models a symbol timing offset (STO) with respect to the guard period and the maximum access delay time for asynchronous multicarrier code division multiple access (MC-CDMA) uplink systems over frequency-selective multipath fading channels. Analytical derivation shows that STO causes desired signal power degradation and generates self-interferences. This effect of the STO on the average bit error rate (BER) and the effective signal-to-noise ratio (SNR) is evaluated. The approximated BER and the SNR loss caused by STO are then obtained as closed-form expressions. The tightness between the analytical result and the simulated one is verified for the different STOs and SNRs. Furthermore, the derived analytical results are verified via Monte Carlo simulations.

A Study on a Design for the Korean Coast Guard Uniform (한국 해양경찰복제 디자인 연구)

  • Lee, Jae-Jung;Kim, Youn-Hee
    • Journal of the Korean Society of Costume
    • /
    • v.61 no.5
    • /
    • pp.1-20
    • /
    • 2011
  • As a follow-up of a study on design strategies to improve Korea's Korean coast guarduniforms, this study set out to propose Korean coast guard uniforms of a new concept that would meet the changing needs of the times and match the advanced technology and work environments. Three concepts of classical, nautical and techno chic were identified from the design strategies of the previous study. Using the results from a prototype show and preference survey, the investigator divided items into design, color, material, and detail and reflects demands for each of them. As a result, design was examined in four aspects of identity, acknowledgement, unity, and practicality and focused its improvement factors on design differentiated from other organizations' uniforms including ground police, segmentation of size system, adjustment of the length of upper garment to consider activity, and changes to the lines and silhouette to give out a modern image. As for color, the focus was placed on differentiated colors from other organizations' uniforms including ground police through dark blue and ocean color, change toward colors that reflect environmental characteristics, and unity in colors between the summer and winter uniform. As for material, the focus of improvement was put on elasticity, resistance against contamination, warmth retention, texture, wearing sensation, and functionality by taking into account convenience for field workers on coast guard vessels and branch offices who have much time in contact with ocean environments in order to make the materials high-grade. As for detail, structural details were added to give out a modern image such as changing the detail lines, efficiency of storage space, buttons, sleeve hems, ironing lines, and neck collars by taking into account environmental characteristics. The significance of the study lies in that it proposed a development model for large-scale uniform copy design by establishing copy design that secures functionality and is proper for an organization's social and cultural environment.

A Study on the Development of an RFID System for Recreational Boating Safety (RFID 기술을 활용한 해양인명구조 시스템 개발에 관한 연구)

  • Yang, Dong-Shin;Sung, Chul;Choi, Tae-Sung
    • Proceedings of KOSOMES biannual meeting
    • /
    • 2006.11a
    • /
    • pp.119-123
    • /
    • 2006
  • Finding out the exact location of survivors in short period of time is critical to conduct rescue activity successfully in oceans. Current technology with natural circumstances limits the activity that our efforts come along. R&D Center housed at Korea Coast Guard (KCG) has developed the system named "RFID for Life jacket" which enables us to access the location of persons under distressed situation. The RFID has been widely known as state-of-art technology to monitor the location even in inland or in ocean. Composed of tag, antenna. reader and middleware, RFID is attached to attached to a life jacket that people usually wears in recreational activity. By conducting experiments in pilot-scale several times, successful results showing 96.7% of transmission within 3.5km in diameter were produced. This study explains the routes of experiments to reach the goal and expected results coming from this accomplishments.

  • PDF

Benefits and perceived risks of influencing the consumer's willingness to use customization service for rash guard design (래시가드 디자인 커스터마이징 서비스 이용에 영향을 미치는 소비자의 추구혜택과 지각된 위험)

  • Lee, Jung-Woo;Jang, Seyoon
    • The Research Journal of the Costume Culture
    • /
    • v.26 no.4
    • /
    • pp.598-612
    • /
    • 2018
  • This research aims to shed a light on the benefits and perceived risks to the willingness to use perceived by consumers, centering on design-customizing service catering to individuals' tastes and needs, and to study their impacts on the use of a design-customizing service. The validation of how benefits and perceived risks affect the intention to use showed that only aesthetic and self-expressive benefits had significant impacts on the willingness to use. However, only time/economic loss and self-design risks had negative impacts on the willingness to use a service. By gender, there was no difference in benefits and perceived risks to willingness to use for the benefit factors, whereas in terms of perceived risks to willingness to use factors. By age, there were also differences in the effects of benefits and perceived risks to purchase on the willingness to use a rash guard customizing service. There were variations in the perceived risks to the willingness to use and benefits depending on age. In particular, it was found that there were no perceived risks to the willingness to use for the age group of 10s. As design-customizing services based on individual tastes have drawn more attention recently, this research on the benefits and perceived risks to purchasing a rash guard design customizing service, as well as their effects on service use (particularly backed up by comparative analysis by gender and age), is expected to provide insights into design-customizing service strategy development.

A Study on Developing Professional Training of the Private Security Industry (민간경비 산업의 전문인력 양성 방안)

  • Park, Aok-Cheol
    • Journal of the Society of Disaster Information
    • /
    • v.2 no.1
    • /
    • pp.91-111
    • /
    • 2006
  • Technology development of modern society reduces times, costs and labor costs but demands work forces requiring expert knowledge on technology. Consequently knowledge worker becomes important. Not changing into a specialist acquired expert knowledge, people can't survive in competitive society. Therefore, the purpose of this study is to grasp the actual condition of private security industry and to examine problems. The final goal is to find the way to improve the professionalism of workers in private security industry. First. Now we must make up for the subject for examination actually and be in a triangular position and complement a professional materials for teaching. At the same time it must strengthen the education using advanced instruments seek to Total Security System. Moreover it is demanded 'institutional supplement of security guard instructors' which means job training for security guard instructor Second. On the job training which can deal with a state of emergency through 'security guard training' with a theory and an actual training must be strengthen. Also, most security guards have low understandings and interests because their ages are from 50's to 60's. Accordingly proper education must be offered to security guard. Third. Certification system of the private security guards are needed to fix the problems on an indiscreet issue and an abuse of license through deliberation on the security license. Fourth. Universities must find a new market to minimize the squandering of human resources because of oversupply and reduce the personnel. Also with enhancing the employment rate through specialized education, universities must offer an education which keeps pace with the times for not an entrance strategy but a long-term development. Effort for education of specialist will produce an improvement in business quality and improved services produce a customer satisfaction. A customer satisfaction will produce a fame of a successful company and positive images in market area. Finally the private industry will be developed by productivity improvement.

  • PDF

Effect of Working Hours on Fatigue and Fatigue Induced Factor in Private Guard and Security (민간 경호.경비원들의 근무시간이 피로에 미치는 영향)

  • Park, Suk;Jung, Suk-Hyun;Choi, Moo-Young
    • Korean Security Journal
    • /
    • no.17
    • /
    • pp.131-141
    • /
    • 2008
  • The porpuse of present study was to examine the effects of working time on fatigue and fatigue induced factor in private guard and security. The munber of private guard on which this study has been conducted in 200, who work at large conmpanies, medium or small companies and the like as located in Seoul and kyonggi. In this study blood lactate, phosphorus and ammonia were measred to see the level of fatigue. There was significant difference in blood lactate, phosphorus ammonia and fatigue between working hours(P<0.05). in view of the results of this study, it can be thought that fatigue is more affected by working hours In summary, these results are interpreted to mean that 1) fatigue levels and blood fatigue induced factor (lactate, phosphorus, ammonia) increase due to a rise in working hours.

  • PDF

A Legislative consideration on protection and regulation of Assembly and Demonstration at sea (해상 집회 및 시위의 보호와 규율을 위한 입법정책적 고찰)

  • Soon, Gil-Tae
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.21 no.5
    • /
    • pp.524-530
    • /
    • 2015
  • In this study, I present solutions to properly regulate assembly and demonstration at sea which has not been relatively secured and regulated compared to that of on land and inland waters so it may not violate public safety and order, and at the same time to secure it as a basic human right. Firstly, to protect and regulate in the same way with assembly and demonstration on land, I suggest to make amendments to "Law on Assembly and Demonstration" so that Korea Coast Guard Station can accept applications and administrator maritime assembly and demonstration. Secondly, in special cases where there are difficulties in the application of "Law on Assembly and Demonstration" due to the special maritime environment, following the example of Japan, America and England who have regulations in related special laws, I suggest an legislative alternative to add regulations on maritime assembly and demonstration in "Law on Maritime Guard" so that we can administer maritime assembly and demonstration in a way which there should be no conflict between basic human right of people and conservation of public safety.