• Safety and Health at Work
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• v.11 no.2
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• pp.178-186
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• 2020

Background: Cognitive impairment is a public health burden. Our objective was to investigate associations between work hours and cognitive function. Methods: Multi-Ethnic Study of Atherosclerosis (MESA) participants (n = 2,497; 50.7% men; age range 44-84 years) reported hours per week worked in all jobs in Exams 1 (2000-2002), 2 (2002-2004), 3 (2004-2005), and 5 (2010-2011). Cognitive function was assessed (Exam 5) using the Cognitive Abilities Screening Instrument (version 2), a measure of global cognitive functioning; the Digit Symbol Coding, a measure of processing speed; and the Digit Span test, a measure of attention and working memory. We used a prospective approach and linear regression to assess associations for every 10 hours of work. Results: Among all participants, associations of hours worked with cognitive function of any type were not statistically significant. In occupation-stratified analyses (interaction p = 0.051), longer work hours were associated with poorer global cognitive function among Sales/Office and blue-collar workers, after adjustment for age, sex, physical activity, body mass index, race/ethnicity, educational level, annual income, history of heart attack, diabetes, apolipoprotein E-epsilon 4 allele (ApoE4) status, birth-place, number of years in the United States, language spoken at MESA Exam 1, and work hours at Exam 5 (β = -0.55, 95% CI = -0.99, -0.09) and (β = -0.80, -1.51, -0.09), respectively. In occupation-stratified analyses (interaction p = 0.040), we also observed an inverse association with processing speed among blue-collar workers (adjusted β = -0.80, -1.52, -0.07). Sex, race/ethnicity, and ApoE4 did not significantly modify associations between work hours and cognitive function. Conclusion: Weak inverse associations were observed between work hours and cognitive function among Sales/Office and blue-collar workers.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.10
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• pp.28-33
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• 2009

In this paper, we propose the receiver algorithms suitable for the VHF (Very High Frequency) digital link mode-2(VDL Mode-2) system. Unlike conventional digital communication systems using the root raised cosine filter as a transmit and receive filter, raised cosine filter is used as a transmit filter in the VDL Mode-2 system. Hence, it is crucial to design and implement the optimum lowpass receive filter by considering inter-symbol interference and noise performance. On the other hand, due to the short preamble pattern, it is crucial to develop an efficient packet detection algorithm for reliable communication link for the VDL Mode-2 system. Also, frequency offset due to the carrier frequency difference between transmitter and receiver and doppler frequency shift must be estimated and compensated for reliable communication. In this paper, the optimum receive filter, packet detection and frequency offset compensation algorithms are proposed and the performance of the VDL system employing the proposed algorithms are evaluated.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.184-188
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• 2008

This study presented simple and efficient fabrication of chemical sensors for the detection of acidic gas using 1,3-bisdicyanovinylindane as an indicator because it can be promising materials having property of the rapid color change according to the variation of pH. The dissociation of proton and dye in acidic condition as changing of ion pairs give rise to dramatically change the absorbance intensity of 1,3-bisdicyanovinylindane, which can be easily applied to the development of chemical sensors. In addition, indicator dyes having negatively charge in aqueous phase can be easily fabricated using layer-by-layer (LBL) methods by way of electrostatic interaction. For the proof of concept, we demonstrated the abrupt presentation of skeleton symbol on the chemical sensor, which could be resulted from the reaction of 1,3-bisdicyanovinylindane as background color with acidic gas. Thus, the rapid appearance of symbol will induce user's caution under the emergency condition. The presented chemical gas sensor using 1,3-bisdicyanovinylindane have strong advantages. First, the fabrication process of gas sensor was very simple and low-cost. Secondly, sensors reacted by acidic gas could be reused for several times. Finally, the chemical gas sensor would be environmentally friend, which can be a basic tool for the realization of eco-organic sensor device.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.69-69
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• 2017

농기계의 대형화, 고성능화로 장치가 복잡해지면서 안전표지 및 조작표시의 역할이 증대되고 있으나 기존에 제정된 KS B 7947의 경우 ISO표준 도안 및 작도방법을 준용하지 않고 있어 기호가 조잡하고 복잡하며 명확히 이해하기 어려워 산업체의 활용도가 낮은 상황이며, 제조사별로 상이한 도안을 사용하고 있는 실정이다. 따라서 ISO표준 도안 및 작도방법을 준용하여 그래픽 심볼 도안을 개정하여 산업체의 활용도가 높아져 조작표시를 농업인이 쉽게 인식하고 이해하여 위험 등을 피할 수 있도록 하여 사고 예방에 기여할 수 있도록 하는 것이 중요할 것이다. 본 연구에서는 안전표지 및 조작표시를 ISO 표준 도안 및 작도방법을 준용하여 작성하기 위한 방법을 연구하고 KS B-7946에 제시된 65개 항목 중 일본과 미국에서 동시에 사용되고 있는 항목 4개는 유지하고 10개 항목은 삭제하며, 승용 동력운반차, 매연저감 장치 등 11개 항목을 추가하고 40개 항목의 수정을 통하여 국내 농기계 관련 안전표지 및 조작표시의 그래픽 심볼을 개선하고 그 결과를 ISO에 국제표준 규격도안 추가 및 개정을 제안하고자 수행되었다.

• The Korean Journal of Food & Health Convergence
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• v.6 no.1
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• pp.17-20
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• 2020

Wheat is the most abundant crop in the world, accounting for one third of the world's population diet. In Ukraine, wheat is in fact, in addition to its nutritional value, a national symbol of the state. Therefore, the main thesis on the development of modern plant growing in Ukraine is the reduction of costs and the introduction of innovative technologies. The quality of grain and seed depends on many factors, namely: agro-climatic conditions, sowing condition of the seed material, quality characteristics of the soil, yielding properties of seeds, pre-sowing seed treatment. etc. For this purpose, the photosynthesis and intensity of photosynthesis need to be limited to the width of the leaf and the height of the leaves by a smaller cut of the stem. It is extremely important to ensure that the head and side pagons of wheat are in good condition. All parameters are often secured by the technology of grain preparation before delivery. Prior to this technology, it is possible to introduce processing of the material in the form for the development of the material. This article presents the effectiveness of the use of infrared irradiation for the pre-sowing treatment of winter wheat seeds in Sekobra Research, Germany.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1364-1373
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• 2016

Ultra High Definition Television (UHDTV) has attracted much attention as one of next generation broadcasting services. For the commercialization of UHD broadcasting service, standardization groups including the DVB (Digital Video Broadcasting) and the ATSC (Advanced Television Systems Committee) have decided to adopt the Orthogonal Frequency Division Multiplexing (OFDM) for signal transmission. However, when the carrier frequency is not properly synchronized at the receiver, inter-symbol interference (ISI) and inter-carrier interference (ICI) may occur. In order to avoid performance degradation resulting from ISI or ICI, receivers should synchronize the carrier frequency by using preambles and pilot symbols. However, there only few published literature dealing with the frequency offset estimation methods regarding the next generation terrestrial broadcasting. In this respect, this paper proposes a method to estimate timing and fractional frequency offset for the ATSC 3.0 system by using a preamble bootstrap symbol. The proposed detector can detect the fractional frequency offset by adding a complex conjugate product on the conventional estimator where only timing offset can be estimated.

• Archives of design research
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• v.18 no.2 s.60
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• pp.189-200
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• 2005

Paper currency is a cultural symbol sign representing identity of a nation as well as a tool of barter system and a measure of value. The purpose of this study is to analyze the design characteristics shown in the pattern of the paper currencies of advanced countries and Korea and to make comparative analysis of the image type of each nation as a cultural code. The results show that 1) the usability of paper currency design was evaluated by denominations, size type, color, braille system and the paper currencies of Switzerland and EU were judged superior to those of the other counties. 2) The national image type represented paper currencies was classified as 'state oriented type' and 'culture & art oriented type'. The countries of Korea, U.S.A, Japan etc. have on the paper currencies the ruling class who contributed to organizing the national system foundation emphasizing their nationalism. In the case of European countries, their paper currencies reveal a variety of citizen who have contributed to art, science, music, architecture without distinction of gender and this fact puts an emphasis on egalitarianism and equality of both senders and importance or cultural art. 3) Paper currency design of Switzerland, Netherlands, France, U.K. was visualized as an art work with utilization of work-type subject, brilliant color, CG technique, unique layout etc. This study provides us with a valuable opportunity to examine the present state of the Korean paper currencies design in Comparison With those of the world's advanced countries. It is expected that this study could be a resource material for new paper currency design and emphasize the importance of the paper currencies representing a national image as a cultural design.

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.207-215
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• 2011

A signal passed through multi-path channel suffers ISI(Inter-Symbol Interference) and severe distortions caused by channel delay spread and noise components at the SC-FDE(Single Carrier with Frequency Domain Equalizer) transmission. Conventional UW(Unique-Word) based SC-FDE iterative channel estimation improves channel estimation performance by smoothing estimated CIR(Channel Impulse Response) of the noise components outside the channel length at time domain and restoring the broken cyclic property through UW reconstruction. In this paper, we propose channel estimation scheme through noise suppression within channel length. To suppress the noise, we estimate noise standard deviation as estimated CIR of the noise components outside the channel length and make criteria of the noise standard deviation gain that doesn't affect the original signal samples. When estimated CIR samples within channel length are less than the criteria value using the noise standard deviation and gain, the noise components are removed. Simulation results show that the proposed channel estimation scheme brings good channel MSE(Mean Square Error) and good BER(Bit Error Rate) performance.

• Korean Journal of Construction Engineering and Management
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• v.24 no.2
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• pp.13-23
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• 2023

Unlike building construction projects, where the activity is repeatedly carried out in a limited area, civil engineering projects such as roads and railroads are carried out in a linear type in a horizontal working space over several tens of kilometers. Each activity is managed with a station number that has a unit of distance from the starting point to the end point. For this reason, since the work location information of the activity is a major management factor, the Gantt chart system that expresses only schedule information may have limitations. In this study, authors propose a method for constructing a linear schedule chart that can simultaneously express schedule information indicating the start and finish dates and location information indicating the start and end positions of each activity, and develop a system for generating a linear schedule chart. In the study, the coordinate axes of the linear schedule chart consisted of distance and date values on the X and Y axes, respectively, and each activity was expressed as a symbol that can infer the type of work to increase the visibility of the linear schedule chart compared to the simple bar chart method. The linear schedule chart generation system was reviewed for practical applicability by utilizing the actual schedule data of bridge structures in a railroad project.

• Journal of the Korea Furniture Society
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• v.23 no.2
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• pp.103-109
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• 2012

King Muryeong reungeseo Foot-rest on the subject of the king excavated a USB memory design. Foot-rest of the form and the meaning of patterns were expressed on a USB memory. Minds of ordinary people in these times communicator acts as an intermediary in the sky to give a sense of the king, such as Foot-rest patterns carved on the engraved turtle. Closely related to modern life, as cultural products associated with the computer by connecting supplies of products for some tourists, not only about reaching the wider public should focus on development. Meanwhile, the USB memory could not be seen in the case of natural wood material by using the age and the individual tastes of consumers represents USB memory into the merit of portability, necklaces pendants items for restoration, phone strap, key chain, etc. By combining the functionality increases. Meanwhile, on the basis of a practical item, the largest issue was the consumption of cultural products by maximizing the economic benefit of the community and at the same time a symbol of cultural heritage items have been transformed into the effectiveness of the national image enhancement is expected to be achieved.