• The Journal of the Acoustical Society of Korea
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• v.30 no.6
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• pp.308-314
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• 2011

This paper presents techniques for estimating directions of multiple sound sources ranging from $0^{\circ}$ to $360^{\circ}$ using circular probability distributions having a periodic property. Phase differences containing direction information of sources can be modeled as mixtures of multiple probability distributions and source directions can be estimated by maximizing log-likelihood functions. Although the von Mises distribution is widely used for analyzing this kind of periodic data, we define a new class of circular probability distributions from Gaussian and Laplacian distributions by adopting a modulo operation to have $2{\pi}$-periodicity. Direction estimation with these circular probability distributions is done by implementing corresponding EM (Expectation-Maximization) algorithms. Simulation results in various reverberant environments confirm that Laplacian distribution provides better performance than von Mises and Gaussian distributions.

• Physical Therapy Korea
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• v.8 no.4
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• pp.45-61
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• 2001

본 연구는 보행주기 동안 정상인과 당뇨병성 족부궤양 환자의 족관절 운동역학적 변수와 족관절 근육들의 근활성도에 차이가 있는지 알아보기 위하여 실시하였다. 본 연구의 대상자는 당뇨병성 족부궤양이 있는 환자 9명(남자: 6명, 여자: 3명)과 성, 연령, 체중으로 짝짓기(matching)시킨 대조군 9명이었다. 3차원 동작분석기, 힘판, 표면 근전도를 이용하여, 보행주기 동안 족관절의 관절가동범위, 모멘트(moment), 일률(power), 그리고 내측가자미근, 전경골근, 비복근의 근수축 개시시간(onset time)과 종료시간(cessation time)을 측정하였다. 정상군과 비교하여 당뇨병성 족부궤양군의 보행속도는 느렸고, 입각기 기간이 길었으며, 족관절의 가동범위가 적었고, 족관절 최대 족저굴곡 모멘트와 일률이 정상군에서보다 유의하게 낮았다. 보행주기에서 당뇨병성 족부궤양군에서 내측 가자미근과 비복근의 근수축 개시시간은 유의하게 빨랐으며, 전경골근과 비복근의 근수축 종료시간은 유의하게 지연되었다. 당뇨병성 족부궤양 환자군의 족관절 근육에서 동시수축(co-contraction)이 증가되고, 보행속도가 느리며, 입각기 기간이 증가하였다. 이러한 보행특성의 차이는 족부 감각손실에 따른 보행의 안정성을 유지하기 위한 보행전략 때문으로 판단된다. 앞으로 이러한 비정상적인 보행특성이 당뇨병성 족부궤양에서 발생하는 비정상적인 족저부 압력분포과 족부궤양 발생과 어떤 관계가 있는지 알아보는 연구가 필요할 것이다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.142-149
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• 2015

Most of the mono-camera based lane detection systems are fragile on poor illumination conditions. In order to compensate limitations of single sensor utilization, lane information fusion system using multiple lane sensors is an alternative to stabilize performance and guarantee high precision. However, conventional fusion schemes, which only concerns object detection, are inappropriate to apply to the lane information fusion. Even few studies considering lane information fusion have dealt with limited aids on back-up sensor or omitted cases of asynchronous multi-rate and coverage. In this paper, we propose a lane information fusion scheme utilizing multiple lane sensors with different coverage and cycle. The precise lane information fusion is achieved by the proposed fusion framework which considers individual ranging capability and processing time of diverse types of lane sensors. In addition, a novel lane estimation model is proposed to synchronize multi-rate sensors precisely by up-sampling spare lane information signals. Through quantitative vehicle-level experiments with around view monitoring system and frontal camera system, we demonstrate the robustness of the proposed lane fusion scheme.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.4
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• pp.271-282
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• 2015

External cost is cost imposed on a third party when producing or consuming a good or service. Since the 1990s, the external costs of nuclear powered electricity production have been studied. Costs are a very important factor in policy decision and the external cost is considered for cost comparison on electricity production. As for nuclear fuel cycle, a chosen technology will determine the external cost. However, there has been little research on this issue. For this study, methods for external cost on nuclear power production have been surveyed and analyzed to develop an approach for evaluating external cost on nuclear fuel cycles. Before the Fukushima accident, external cost research had focused on damage costs during normal operation of a fuel cycle. However, accident cost becomes a major concern after the accident. Various considerations for external cost including accident cost have been used to different studies, and different methods have been applied corresponding to the considerations. In this study, the results of the evaluation were compared and analyzed to identify methodological applicability to the external cost estimation with nuclear fuel cycles.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.291-296
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• 2015

The tire damage classification method is researched on the periodicity detection of ramdomness ultrasonic signals to occur at the driving vehicle tire. Setting method of adaptive threshold is proposed in order to valid pulse detection by tire damage in ultrasonic noise on the road and used low pass filter for decrease signal ramdomness as preprocessing. Time interval of detected pulse is setted the density function depend on the vehicle's speed and the method of tire damage detection is proposed that measuring the first peak's time of time density function.The result of time density function in case of one damage material, the first peak's time is measured within the error limit of tire's rotation period, 169.8ms and 97.9ms and 81.8ms, about the speed of 50km/h and 80km/h and 100km/h. In case of more than one damage material, the sum of each peak's time is measured within the error limit of tire's rotation period about the speed.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.674-678
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• 2011

The model to estimate potential evapotranspiration (PET) was developed using periodic function. Average PET during 30 years for 67 areas was $2.36mm\;day^{-1}$, and those were distributed with the range of $1.42{\sim}3.45mm\;day^{-1}$. The period of PET change was 16~32 years according to area.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.1
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• pp.61-67
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• 2000

Digital controllers found in many industrial real-time systems consist of a number of interacting periodic tasks. To sustain the required control quality, these tasks possess the maximum activation periods as performance constraints. An essential step in developing a real-time system is thus to assign each of these tasks a constant period such that the maximum activation requirements are met while the system utilization is minimized [1]. Given a task graph design allowing producer/consumer relationships among tasks [2], resource demands of tasks, and range constraints on periods, the period assignment problem falls into a class of nonlinear optimization problems. This paper proposes a ploynomial time approximation algorithm which produces a solution whose utilization does not exceed twice the optimal utilization. Our experimental analysis shows that the proposed algorithm finds solutions which are very close to the optimal ones in most cases of practical interest.

• Korean Journal of Agricultural Science
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• v.11 no.2
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• pp.233-243
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• 1984

The present study was carried out to determine the changes of the sex hormone levels in serum throughout the estrous cycle and the gestation period on the Landrace gilts. The blood samples were taken from the vein of six gilts. LH, FSH, prolactin, progesterone, $estradiol-17{\beta}$ and cortisol in serum were analyzed by the radioimmunoassay methods. The results obtained on this study were summarized as follows; 1. The age at puberal estrus was 179.5 days, the weight at puberal estrus was 88.2kg, the length of estrous cycle was 21.3days, the gestation length was 114days and the litter size was 9.5 head in the Landrace gilts. 2. During the estrous cycle, the serum LH and prolactin concentrations were below 1.56mIU/ml and 2.4ng/ml, respectively, under the limit of detection of the assay. The FSH concentrations ranged from 1.50 to 2.20mIU/ml for day 6~15 after the estrus and they were below 1.25mIU/ml from day 3 to day + 3, with day 0 being the first day of the estrus. 3. Progesterone concentrations were 1.90ng/ml at day 0 of the estrus and increased about 13.1ng/ml at day 3 of the estrus, and reached peak levels at day 9. $Estradiol-17{\beta}$ concentrations were below 27.2pg/ml throughout the luteal phase, and reached about 27.2pg/ml at day 0 and day 18. Cortisol concentrations reached peak levels at dey 0 and ranged from 24.65 to 28.57ng/ml throughout the luteal phase. 4. During the gestation period, the concentrations of LH, FSH and prolactin ranged of 3.10~4.37mIU/ml, 1.30~1.80mIU/ml and 2.60~6.70ng/ml, respectively. 5. Progesterone concentrations declined from 38.90~16.85ng/ml throughout the pregnancy to 1.90ng/ml at the time of parturition. $Estradiol-17{\beta}$ concentrations increased from 27.20pg/ml at 15 days after the pregnancy to 620.17pg/ml at the time of parturition. Cortisol concentrations reached peak levels at the time of parturition and ranged from 13.58 to 22.31ng/ml throughout the pregnancy.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.605-617
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• 2015

The ultimate goal of this research is to develop a botanical biofiltration system that combines a green interior, biofiltering, and automatic irrigation to purify indoor air pollutants according to indoor space and the size of biofilter. This study was performed to compare the stability of air flow characteristics and removal efficiency (RE) of fine dust within a wall-typed (vertical) botanical biofilter depending on humidifying cycle and to investigate RE of volatile organic compounds (VOCs) by the biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be suitable for indoor space utilization. As a result, relative humidity, air temperature, and soil moisture content (SMC) within the biofilter showed stable values regardless of three different humidifying cycles operated by the metering pump. In particular, SMCs were consistently maintained in the range of 27.1-29.7% during all humidifying cycles; moreover, a humidifying cycle of operating for 15 min and pausing for 45 min showed the best horizontal linear regression (y = 0.0008x + 29.09) on SMC ($29.0{\pm}0.2%$) during 120 hour. REs for number of fine dust (PM10) and ultra-fine dust (PM2.5) particles passed through the biofilter were in the range of 82.7-89.7% and 65.4-73.0%, respectively. RE for weight of PM10 passed through the biofilter was in the range of 58.1-78.9%, depending on humidifying cycle. REs of xylene, ethyl benzene, total VOCs (TVOCs), and toluene passed through the biofilter were in the range of 71.3-75.5%, while REs of benzene and formaldehyde (HCHO) passed through the biofilter were 39.7% and 44.9%, respectively. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was very effective for indoor air purification.

• Journal of the Korean Society for information Management
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• v.22 no.3 s.57
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• pp.351-378
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• 2005

The study intended to develop KORMARC for archives in order to integrate archives with library materials. The results of the study can be summarized as follows; (1) 2 areas for conservation and physical description are added to the existing 7 areas of ISAD(G)2. The study has also proved that the existing 26 elements of ISAD(G)2 are not fully enough to satisfy the information demands' of institutions and its users as well. (2) For the use of domestic archives in particular, the study has added the description elements of archives that appeared in the Government Regulations of Office Management and those forms of documents that are specified by law for the sake of computerization. The study has added the possible release and grade, release dates, release range, conservation periods, conservation periods, conservation value, the status description of archives elements that are specified in Public Record Management Law. (3) The study has developed the following data fields to be added into KORMARC. 512 creation dates note, 555 finding aids note, 583 action note and 584 accumulation note. Also it reorganizes and adds the indicators of the 245 title statement, 300 physical description 306 playing time, 506 restriction on access note, 534 original version note, 535 location of originals/duplicates note, 540 terms governing use and reproduction notes, 541 immediate source of acquisition note, 545 biographical or historical note, 581 publication note, 850 holding institution data fields.