• 제목/요약/키워드: effective period

검색결과 5,156건 처리시간 0.032초

Throughput Analysis of CSMA/CA-based Cognitive Radio Networks in Idle Periods

  • Wang, Hanho;Hong, Daesik
    • IEIE Transactions on Smart Processing and Computing
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    • 제3권4호
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    • pp.173-180
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    • 2014
  • Random access protocols feature inherent sensing functionality and distributed coordination, making them suitable for cognitive radio communication environments, where secondary users must detect the white space of the primary spectrum and utilize the idle primary spectrum efficiently without centralized control. These characteristics have led to the adoption of carrier-sensing-multiple-access/collision-avoidance (CSMA/CA) in cognitive radio. This paper proposes a new analytical framework for evaluating the performance of a CSMA/CA protocol that considers the characteristics of idle periods based on the primary traffic behavior in cognitive radio systems. In particular, the CSMA/CA-based secondary network was analyzed in the terms of idle period utilization, which is the average effective data transmission time portion in an idle period. The use of the idle period was maximized by taking its statistical features into consideration.

정렬과 평균 정규화를 이용한 2D ECG 신호 압축 방법 (2D ECG Compression Method Using Sorting and Mean Normalization)

  • 이규봉;주영복;한찬호;허경무;박길흠
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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    • pp.193-195
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    • 2009
  • In this paper, we propose an effective compression method for electrocardiogram(ECG) signals. 1-D ECG signals are reconstructed to 2-D ECG data by period and complexity sorting schemes with image compression techniques to Increase inter and intra-beat correlation. The proposed method added block division and mean-period normalization techniques on top of conventional 2-D data ECG compression methods. JPEG 2000 is chosen for compression of 2-D ECG data. Standard MIT-BIH arrhythmia database is used for evaluation and experiment. The results show that the proposed method outperforms compared to the most recent literature especially in case of high compression rate.

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가정용(家庭用) 가스 보일러의 보증기간내(保證期間內) 수리율(修理率)에 관(關)한 실증적(實證的) 연구(硏究)(I) (An Empirical Study on the Repair Rate of Domestic Gas Boiler within Warranty Period(I))

  • 한재훈;김봉선
    • 대한안전경영과학회지
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    • 제16권1호
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    • pp.139-146
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    • 2014
  • As Crosby notes, the most companies spend 15 to 20% of their sales dollars on quality costs. Generally the most effective way to manage quality costs is to avoid having defects in the first place. In this paper we have studied about the repair(service) problem of domestic gas boiler within warranty period. We develop a system, which man could find the cause of the problem at an early stage and could devise a countermove to the problem under supposing that the service(repair) rate follows exponential distribution and the product is manufactured lot-for-lot continually. Using the developed early sensing system. it is expected to improve the reliability of the product, to save expenses of company and to improve customer's satisfaction. And the system will be expended to incorporate information technology, which can detect the repair rate automatically.

COLOR EXCESSES AND PERIOD-COLOR RELATION OF CLASSICAL CEPHEIDS

  • Kim, Chul-Hee;Moon, B.K.;Yushchenko, A.V.
    • 천문학회지
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    • 제43권5호
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    • pp.153-159
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    • 2010
  • Color excesses of classical Cepheids in the uvby color system are estimated for the calibration stars with distances from the literature that are measured independently. Intrinsic photometric indices for these stars are calculated and a calibrated empirical relation between (b - y)$_0$, period, [$c_1$], and [$m_1$] is derived through a linear fit. This relation is used to determine color excesses E(b-y) for 59 Cepheids. We also examine the period-color [log P : (b - y)$_0$] relation, and find no signs of nonlinearity. We estimate the effective temperature and surface gravity of several Cepheids using both Kurucz and MARCS/SSG grids for [Fe=H]=0.0. We confirm that both temperature and surface gravity are higher, by about 150K and 0.4 respectively, when the MARCS/SSG atmospheric grids are used.

배기관 내 압력 변동 분석에 의한 가솔린 기관의 실화 검출 (Misfire Detection of a Gasoline Engine by Analysis of the Variation of Pressure in the Exhaust Manifold)

  • 심국상;복중혁;김세웅
    • 한국자동차공학회논문집
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    • 제7권5호
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    • pp.1-8
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    • 1999
  • This paper describes the method for detection of the misfired cylinder by analysis of the variation of pressure occurred in exhaust manifold on an MPI gasoline engine. Misfired cylinder(s) cause a loss of power, an increase of fuel consumption and exhaust emission and vibration is caused by unsteady torque. Therefore early detection and correction of misfired cylinder(s) play a very important role in the proper performance and the exhaust emission. The method is a comparison of integration pressure index during the period of a blowdown in the displacement period. Experimental results showed that the method, using the variation of pressure in the exhaust manifold is proven to be effective in the detection of single cylinder or multiple cylinders misfire on the gasoline engine regardless of the engine revolutions. In addition, this method, using the variation of pressure in the exhaust manifold is a very easy and accurate method compared with other methods.

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Development of nationwide amplification map of response spectrum for Japan based on station correction factors

  • Maruyama, Yoshihisa;Sakemoto, Masaki
    • Earthquakes and Structures
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    • 제13권1호
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    • pp.17-27
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    • 2017
  • In this study, the characteristics of site amplification at seismic observation stations in Japan were estimated using the attenuation relationship of each station's response spectrum. Ground motion records observed after 32 earthquakes were employed to construct the attenuation relationship. The station correction factor at each KiK-net station was compared to the transfer functions between the base rock and the surface. For each station, the plot of the station correction factor versus the period was similar in shape to the graphs of the transfer function (amplitude ratio versus period). Therefore, the station correction factors are effective for evaluating site amplifications considering the period of ground shaking. In addition, the station correction factors were evaluated with respect to the average shear wave velocities using a geographic information system (GIS) dataset. Lastly, the site amplifications for specific periods were estimated throughout Japan.

보바스 개념에 기초한 슬링 운동이 양하지 뇌성마비 균형에 미치는 영향: 단일사례연구 (The Effects of Sling Exercise Based with Bobath Concept on the Balance of Spastic Diplegia Cerebral Palsy: Case Report)

  • 이은주
    • 신경치료
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    • 제22권3호
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    • pp.11-18
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    • 2018
  • Purpose This study is to investigate the effect of sling exercise on the balance capacity of spastic diplegia cerebral palsy patient based on Bobath concept. Methods A single subject experiment was designed targeting an 8year old child with the rigid bilateral cerebral palsy. The static balance test used the 30 second Rombug test of BT4, and the dynamic balance test used the timed up and go test. Results In the 30second Rombug test of BT4, the child had a smaller median outcome than baseline and withdrawal period. In the TUG test, the walking speed in the intervention period was improved comparing to the baseline and withdrawal period. Conclusion The sling exercise based on the Bobath concept has been proved that it is an effective intervention to improve the static and dynamic balance capacity of patients with rigid bilateral cerebral palsy.

애구(艾灸)의 연소(燃燒) 시간(時間)에 대한 실험적(實驗的) 연구(硏究) -구간별(區間別) 발현(發現) 시점(時點)을 중심(中心)으로- (An Experimental Study of Moxa-Combustion Time by the Density of Moxa Material -On the point of time in the combustion stage-)

  • 박영배;강성길;고형균;오환섭
    • 대한한의학회지
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    • 제15권2호
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    • pp.241-252
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    • 1994
  • It is known that the pattern of combustion temperature can be classified into preheating, heating. retaining and cooling periods. In this experiment. the authors have studied the heating mechanism by the density of moxa material during the heating and retaining periods. The starting point. the point at which it begins to reach the maximum gradient temperature. the ending point of the heating period. and the ending point of the retaining period were measured in order to get effective stmulation by repetition of moxa-combustion. For the experiment. samples of 300mg. 400mg, and 500mg of moxa material were molded into conical molds with each 10mm in diameter and height resulting in the volume of $0.26cm^3$. The following results were obtained: The $300mg/0.26cm^3$ denstiy sample reached al1 points tested faster than the samples of $400mg/0.26cm^3$ and $500mg/0.26cm^3$ It dose not reveal any statistical differences between $400mg/0.26cm^3$ and $500mg/0.26cm^3$ in the ending point. the point at which it begins to reach the maximum gradient temperature of the heating period or the ending point of the reataining period The only difference shown was in the starting point of the heating period. According to the above results. it is concluded that the lower density moxa material reached each point of the the respective period faster than the high density moxa material.

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갑상선 수술에서 수술 중 신경 감시의 효용성: 학습곡선을 중심으로 (Efficacy of Intraoperative Neural Monitoring (IONM) in Thyroid Surgery: the Learning Curve)

  • 곽민규;이송재;송창면;지용배;태경
    • International journal of thyroidology
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    • 제11권2호
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    • pp.130-136
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    • 2018
  • Background and Objectives: Intraoperative neural monitoring (IONM) of recurrent laryngeal nerve (RLN) in thyroid surgery has been employed worldwide to identify and preserve the nerve as an adjunct to visual identification. The aims of this study was to evaluate the efficacy of IONM and difficulties in the learning curve. Materials and Methods: We studied 63 patients who underwent thyroidectomy with IONM during last 2 years. The standard IONM procedure was performed using NIM 3.0 or C2 Nerve Monitoring System. Patients were divided into two chronological groups based on the success rate of IONM (33 cases in the early period and 30 cases in the late period), and the outcomes were compared between the two groups. Results: Of 63 patients, 32 underwent total thyroidectomy and 31 thyroid lobectomy. Failure of IONM occurred in 9 cases: 8 cases in the early period and 1 case in the late period. Loss of signal occurred in 8 nerves of 82 nerves at risk. The positive predictive value increased from 16.7% in the early period to 50% in the late period. The mean amplitude of the late period was higher than that of the early period (p<0.001). Conclusion: IONM in thyroid surgery is effective to preserve the RLN and to predict postoperative nerve function. However, failure of IONM and high false positive rate can occur in the learning curve, and the learning curve was about 30 cases based on the results of this study.

각기 다른 유기물이 투여된 토양에서 토양의 화학적, 미생물학적 특성과 미생물의 다양성에 미치는 생물비료의 효과 (Effects of a Biological Amendment on Chemical and Biological Properties and Microbial Diversity in Soils Receiving Different Organic Amendments)

  • 박기춘;로버트 크레이머
    • 한국토양비료학회지
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    • 제40권4호
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    • pp.234-241
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    • 2007
  • 여러가지의 선발된 미생물로 구성된 미생물비료는 토양 개량과 식물 생장 촉진을 위해서 여러 유기물과 결합하여 이용되기도 한다. 미생물 비료를 미생물 비료 단독으로 그리고 도시 가로수 부산물 퇴비, 가금류 분뇨 부산물, 레드클로버와 귀리의 피복작물 등의 유기물과 같이 토양에 처리하여 토양의 화학적 또는 생물학적 특성에 미치는 효과를 측정하였다. 액체상의 미생물 비료를 2년동안 3회 처리하였다. 미생물 비료 단독으로는 pH, K, 유기물 함량에 영향을 미치지 않았지만, 미생물비료의 처리는 2년 가을 모두 가금류 분뇨 부산물을 처리한 토양의 인산 함량을 증가시켰고, 첫해 가을에 퇴비를 처리한 토양의 칼슘함량을 증가시켰으며, 레드클로버를 처리한 토양의 Ca, Mg, 그리고 양이온교환용량을 감소시켰다. 미생물 비료는 레드클로버가 처리된 토양에서 첫 해 7월에 탈수소효소 활성을 증가시켰다. 미생물 비료는 유기물이 처리되지 않은 토양이나 퇴비가 처리된 토양에서 FDA의 가수분해도를 가끔 증가시켰다. 가금류 분뇨 부산물과 레드 클로버가 처리된 토양의 FDA 가수분해도와 가금류 분뇨 부산물이 처리된 토양의 탈수소효소활성은 미생물 비료의 처리로 감소하였다. 한편, 미생물 비료의 처리는 BIOLOG에 의한 토양 미생물 군락의 생리생태적 다양성에는 영향을 미치지 못했다. 따라서 토양의 미생물학적 특성에 미치는 미생물비료의 효과는 같이 투여되는 유기물의 종류에 따라 다양하다고 할 수 있으며, 탈수소효소의 활성은 레드클로버가 처리된 토양에서, 그리고 FDA 가수분해도는 퇴비와 귀리가 처리된 토양에서 가끔 증가했다.