• Title/Summary/Keyword: nature frequency

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A Study on Calamity Index Evaluation Based on FRAT - Construction Safety - (FRAT을 이용한 재해평가지수 연구 - 건설업을 중심으로 -)

  • Park, Tae-Hyun
    • Journal of the Korea Safety Management & Science
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    • v.9 no.6
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    • pp.31-38
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    • 2007
  • The construction industry by its nature retains higher level of danger where the smallest of error may lead to a major catastrophe endangering many workers and public safety as well as provoke social criticism. With the aid of quantitative statistical data on safety-related calamity analyzed till this day, this paper handled in depth the analysis of diseases other than the accidents, and selected new variable indexes that influence the indirect sections of calamity that are mostly concealed and incorporated them in a new model. For the factor selection of new calamity evaluation model, FRAT(Frequency, Recency, Amount, Type of merchandise/service)technique of customer-related management in marketing was applied, and as for the significance of each factor in the weight selection of variables. Consequently, considering the graveness of the FRAT itself through safety management experts, the related researches must be expanded.

Spondylodiscitis Misdiagnosed as Spinal Stenosis and Compression Fracture -A report of two cases- (요척주관 협착증과 압박 골절로 오인된 척추 추간판염 2예 -증례보고-)

  • Hong, Ji Hee;Kim, Sae-Young;Han, Sung Ho
    • The Korean Journal of Pain
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    • v.22 no.2
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    • pp.176-180
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    • 2009
  • Cases of pyogenic spondylodiscitis are relatively rare diseases that concern 2-7% of total cases of osteomyelitis. Owing to the low frequency and initial nonspecific nature of signs and symptoms, diagnosis is often delayed up to 2-6 months. If the proper treatment is not established due to a diagnostic delay, there is a possibility of a serious neurologic deficit and spinal instability. We report two cases of infectious spondylodiscitis which were misdiagnosed as compression fracture and spinal stenosis respectively. They could be correctly diagnosed after MRI and laboratory test and under the recovery state after an antifungal and antibiotic medication. Special careful attention during the diagnostic procedure is a really important step considering the diagnostic delay and its resultant unsatisfactory outcome.

Novel Peak-to-Average Power Ratio Reduction Methods for OFDM/OQAM Systems

  • Sandeep, Vangala;Anuradha, Sundru
    • ETRI Journal
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    • v.38 no.6
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    • pp.1124-1134
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    • 2016
  • The tone reservation method is one of the most effective pre-distortion methods for peak-to-average power ratio reduction in orthogonal frequency division multiplexing (OFDM) systems. Its direct application to OFDM systems with offset quadrature amplitude modulation (OQAM) is, however, not effective. In this paper, two novel TR-based methods are proposed, specifically designed for OFDM/OQAM systems by taking into consideration the overlapping nature of OQAM signals. These two methods have different approaches to the generation of the peak-cancelling signal. The first one (overlapped scaling tone reservation) generates the peak-cancelling signal using a least squares approximation algorithm with possible adjacent symbol overlap; the second one (multi-kernel tone reservation) generates the peak-cancelling signal by using multiple impulse-like time domain kernels. It is shown by simulation that, when used in OFDM/OQAM systems, the proposed methods can provide better performance than the direct application of the existing controlled clipping tone reservation method, and even outperform the multi-block tone reservation method.

A Predistorter for OFDM Systems with a Raised Cosine Pulse Shaping Filter and a High Power Amplifier

  • Nam, Choong-Jin;Jang, Hee-Dong;Yoan Shin
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1815-1818
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    • 2002
  • In this paper, a predistorter is presented for the orthogonal frequency division multiplxing (OFDM) systems with a transmit raised cosine (RC) pulse shaping filter and a high power amplifier (HPA). By exploiting zero-intersymbol interference (ISI) nature of the RC filter, the proposed predistorter placed before the filter only utilizes memoryless nonlinearity of the HPA, not the overall nonlinearity with memory induced by a combination of the filter and HPA. The predistirtion is realized upon fixed point iteration on OFDM symbols. Simulation results show that the proposed predisorter can be effectively employed to achieve significant performance improvement.

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The Content Analysis of the Articles Related on Environment (환경관련기사의 내용분석)

  • 정운경
    • Journal of Families and Better Life
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    • v.16 no.1
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    • pp.39-50
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    • 1998
  • This study analyzed the contents of the articles related on Environment in Dong-a & chosun daily newspapers for one year lately. In this study the articles were classified by the theme categories season and nature of messages. Through the result of this study we can understand what were major issues and concerns related on environment lately. The findings can be summarized follows: 1. The identified 757 articles were categorized into eight theme categories. In each theme category the articles on Litter area were reported the most frequently. 2. Also there was no great difference among frequency of the articles by four season but in summer articles on environment were written more frequently and in spring the least. 3. The numbers of informative articles were more than that of directive articles. The recommendations of these results were suggested.

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봉제공업(縫製工業)의 표준시간자료(標準時間資料) 설정(設定)

  • Yeom, Yong-Gwon;Yong, Se-Jung;Hwang, Hak
    • Journal of Korean Institute of Industrial Engineers
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    • v.4 no.1
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    • pp.21-27
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    • 1978
  • For labor-intensive sewing industry, productivity could be enhanced with the proper utilization of standard time system. This paper develops a standard data for sewing operations through three stages. The first is to identify the manual motions from sewing operations. The second is to simplify the MTM-1 data considering the frequency and the nature of basic motions occuring in the operations. Finally we synthesize the standard data using the simplified MTM-1 by the film analysis of the actual operations pictured in the field. The standard data developed is shown to be easier and faster with reasonable accuracy in determining the standard time compared to the MTM-1.

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High-Frequency Analysis of Electromagnetic Backscattering from an Ellipsoid (타원체의 역방향 산란 해석)

  • Shim, Jae-Ruen
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.1
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    • pp.685-688
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    • 2005
  • In this study, an efficient algorithm for the numerical search of the geodesic path of the creeping wave on a doubly curved surface is developed. The ellipsoid as a doubly curved surface is studied because of its three dimensional nature in that it can be used to simulate the body of an aircraft, or a missile body. Numerical result of the geodesic path on an ellipsoid is given.

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Self-field Loss Characteristics of a long Bi-2223/AgMgNi Tape (장척 Bi-2223/AgMgNi 테이프의 자기자계손실 특성)

  • Ryu, Gyeong-U;Park, Gwon-Bae;Cha, Gwi-Su;Choe, Gyeong-Dal;Lee, Ji-Gwang;Han, Song-Yeop
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.4
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    • pp.240-245
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    • 2000
  • The self-field losses in a long multifilamentary Bi-2223/AgMgNi tape with varying transport current, voltage tap configurations, frequency and tape arrangements were investigated. Experimental results show that the measured losses are strongly dependent on voltage gap configurations but independent on tape arrangements. All voltage taps except the center tap are found to agree well with those predicted by Norris for an elliptical conductor. The self-field losses are purely hysteretic in nature in the range of applied frequencies for the transport currents below the critical current.

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연결완전성 제고와 프라이버시 보호를 위한 유비쿼터스 지불 프로세스의 설계

  • Lee, Gyeong-Jeon;Jeong, Mu-Jeong
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2005.11a
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    • pp.226-233
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    • 2005
  • Ubiquitous computing is a study area explained in a myriad of contexts and technological terms. So when you try to define it with simple words, it gets even more confusing. Payment. however, refers in nature to an act of money transfer from one entity to another, and it is obvious that a payment method will be valued as long as the transaction can be completed with safety no matter what technology was used. In the end, the key to U-payment is convenience and security in the transfer of financial information. The purpose of this paper is to find a desirable U-payment scheme by looking at the characteristics of seamlessness under the ubiquitous environments, Strong Personal Device, and peer-based if information transactions. We also propose U-SDT Protocol integrating critical technologies such as Radio Frequency Identification (RFID), Bluetooth, Personal Payment Device, Account Managing Application and Transaction ID as a way to make transactions between users seamless and secure better privacy protection.

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Dielectric Properties of Eicosamethyl Eneasiloxane (Eicosamethyl Eneasiloxane의 유전특성)

  • Cho, Kyung-Soon;Kim, Jae-Hwan;Hong, Jin-Woong
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.1177-1179
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    • 1993
  • A study has been carried out on the characteristics of dielectric consent and the dissipation factor of Eicosamethyl Eneasiloxane as a function of frequency($30{\sim}10^5$[Hz]) and temperature(-70[$^{\circ}C$] to 65[$^{\circ}C$]). The result shows that a well-defined maxima of the absorption curves characterized by a dipole loss mechanism at a low temperature range. For temperatures in the vicinity of room temperature and higher, the loss in the range of power frequencies are predominantly of ionic nature. The increase of ionic conduction is attributed to the presence of ionizable oxidation products and their increased dissocation feature. The effect of viscosity upon the dipole loss intensity appeared to be considerably less pronounced than that upon ionic conduction loss.

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