• 한국정보통신학회논문지
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• 제20권12호
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• pp.2219-2225
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• 2016

이동통신망에서는 채널 사용을 극대화하기 위하여 제한된 송신 전력으로 멀티미디어 트래픽을 지원해야 한다. 실시간 전송 기반의 데이터들은 지연에 민감하므로 이를 고려해야 하고, 비실시간성 데이터는 비교적 지연에 둔감하므로 패킷 손실에 유연하게 대처할 수 있다. 따라서 제한된 송신 전력으로 멀티미디어 트래픽을 지원하여야 하므로 하향 링크 전력을 최소로 유지하면서 QoE 제약 조건을 충족시키는 방안이 필요하다. 전송률의 증가에 따라 소비되는 전력이 크게 증대되므로 다양한 이동 멀티미디어 서비스를 지원하기 위해서는 에너지 소비 절감 기술이 요구된다. 또한 인터넷 기반의 멀티미디어 서비스는 자원 요구량, QoE 요건이 상이하므로 적응적인 전력 관리가 필수적이다. 따라서 본 논문에서는 QoE을 일정 수준으로 충족시키면서 전력 소모를 최소화하기 위한 방안을 제안한다.

• 한국환경과학회지
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• 제13권4호
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• pp.339-347
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• 2004

This paper asks the question: what choice of environmental policy instruments is efficient to reduce sulfur dioxide from stationary sources\ulcorner: In Korea, command and control has been a common way of controlling $SO_2-emissions.$ When compared to the non-incentive environmental policy instrument such as command and control, economic incentive environmental policy instrument has been the advantage of making polluter himself flexibly deals with in marginal abatement cost to develop environmental technology in the long view. Therefore, the application possibility of the incentive environmental policy instrument was studied in this research to realize the countermeasure for controlling of $SO_2-emissions.$ As a result, enforcement of the countermeasure such as flue gas desulfurizer by command and control would be suitable because power generation is performed by the public or for the public in source of air pollution and thus, economic principle is not applied to the polluter. In the source of industrial pollution, enforcement of fuel tax is found to be suitable for the countermeasure for the use of low sulfur oil in terms of the flexibility of demand for the price in the long tenn. For the permissible air pollution standards applicable to all air pollutant emitting facilities, enforcement of incentive environmental policy such as bubble, off-set, banking policy or tradeable emission penn its would be ideal in long terms according to the regional characteristics and the number and scale of air pollutant emitting facilities.

• 한국산업보건학회지
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• 제27권2호
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• pp.87-96
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• 2017

Objectives: Improvement of the reliability of work environment measurement results is one of the principal subjects to be resolved in the field of industrial hygiene. Thus, this study was conducted in order to review domestic programs for enhancing the reliability of work environment measurement results and propose a more efficient management plan for workplace monitoring. Materials and Methods: The current domestic programs reviewed in this study are the quality control system and evaluation system for industrial hygiene laboratories, the reliability system accompanied by KOSHA (the Korea Occupational Safety and Health Agency), the system of permissible exposure limits and observed inspection system for permissible exposure limits. Their contents and data were analyzed by reviewing articles, reports, and guidelines related to reliability improvement for work environment measurement results. Results: As a result of the literature review, all the domestic programs investigated in this study had both merits and demerits in terms of considering the reliability of work environment measurement results. In particular, the fact that preliminary notification is provided to the head of a workplace before implementation would be an obstacle for elevating the reliability of work environment measurement results. Conclusions: Based on the review results obtained from this study, it is proposed that on-site measurement without preliminary notification should be considered for a more efficient inspection system that would enhance the reliability of workplace monitoring.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.139-144
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• 2007

선박에서 발생하는 진동은 여객의 안락감을 결정하거나 승조원의 근무환경에 미치는 영향이 크므로 매우 중요하다 선박에서 발생하는 진동은 선박의 속도를 좌우하는 추진방식의 발달과 가장 밀접한 관계가 있다. 이와 같이 추진력을 발생하기위하여 선박의 기관실에는 디젤엔진의 연속적인 폭발과정에서 기인하는 강력한 진동이 발생하게 된다. 진동이 인체에 미치는 피해는 생리적인 피해와 심리적인 피해로 발생하게 된다. 진동 환경에 인체가 노출되는 경우, 선내의 진동에 대한 평가는 국제표준화지침인 ISO 6954:2000(E)에 의해 정하고 있다. 본 연구에서는 선박에서 진동이 인체에 미칠 수 있는 영향을 평가하기위해 ISO 6954:2000(E)에서 규정하는 지침에 의해 선박진동의 영향이 가장 큰 기관실, 기관제어실, 각종선설 및 브리지 등에서 발생하는 진동의 크기를 측정 비교하여 평가한다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.544-547
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• 2003

The objective of this study is to investigate the contamination levels and dispersion patterns of arsenic and heavy metals and to estimate the bioaccessible fraction of the metals in soil and plant samples in the vicinity of the abandoned Songcheon Au-Ag mine. Tailings, soils, plants (Chinese cabbage, red pepper, soybean, radish, sesame leaves, green onion, lettuce, potato leaves, angelica and groundsel) and waters were collected around the mine site. After appropriate preparation, all samples were analyzed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of As and heavy metals were found in tailings. Mean concentrations of As in agricultural soils were higher than the permissible level. Especially, maximum level of As in farmland soil was 513 mg/kg. The highest concentrations of As and Zn were found in Chinese cabbage (6.7 mg/kg and 359 mg/kg, respectively). Concentrations of As, Cd, and Zn in most stream waters which are used for drinking water around this mine area were higher than the permissible levels regulated in Korea. Maximum levels of As, Cd and Zn in stream waters were 0.78 mg/L, 0.19 mg/L and 5.4 mg/L, respectively. These results indicate that mine tailings can be the main contamination sources of As and heavy metals in the soil-water system in the mine area. The average of estimated bioaccessible fraction of As in farmland soils were $3.7\%$ (in simulated stomach) and $10.8\%$ (in simulated small intestine). The highest value of bioaccessible fraction of metal in farmland soils was $46.5\%$ for Cd.

• 공업화학
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• 제31권3호
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• pp.277-283
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• 2020

본 연구는 건자재용 목재의 연기 유해성평가에 대하여 연기성능지수-II (SPI-II), 연기성장지수-II (SGI-II)를 중심으로 조사하였다. 시험편은 삼나무, 가문비나무, 나왕, 적송을 사용하였다. 연기 특성은 시험편 목재에 대하여 콘칼로리미터(ISO 5660-1) 장비를 이용하여 조사하였다. 연소반응 후 측정된 연기성능지수-II는 적송을 기준으로 1.31~2.15배 증가하였다. 연기성능지수-II에 의한 화재위험성은 가문비나무, 나왕, 삼나무, 적송의 순서로 증가하였다. 연기성장지수-II는 삼나무를 기준으로 1.18~2.55배 증가하였다. 연기성장지수-II에 의한 화재위험성은 삼나무, 가문비나무, 나왕, 적송의 순서로 높아졌다. CO 평균농도는 59~133 ppm이었으며 이 결과는 미국직업안전위생관리국(occupational safety and health administration, OSHA)의 허용기준(permissible exposure limits, PEL)인 50 ppm 보다 높게 나타났다. 결론적으로 적송과 같이 휘발성 유기물질을 다랑 함유한 목재는 연기성능지수-II가 낮고, 연기성장지수-II가 높으므로 화재로 인한 연기유해성이 높은 것으로 이해된다.

• 한국항공우주학회지
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• 제39권11호
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• pp.1069-1076
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• 2011

인공위성이 궤도상에서 임무를 수행하는 동안 모든 위성 부품이 허용 온도 범위 내에서 존재하도록 하기 위하여 검증된 열모델을 개발하고, 궤도 열해석을 통하여 열적 안정성을 확보하기 위한 열설계를 수행한다. 본 연구에서는 저궤도 위성 광학탑재체의 열진공/열평형 시험 결과를 이용하여 열해석 모델을 보정하고 flight heater의 작동주기를 맞추어 줌으로써 검증된 열모델을 확보하였다. 또한 위성의 열적 안정성을 확보하기 위하여 보정이 완료된 모델을 이용하여 궤도 열해석을 수행함으로써 모든 부품이 허용온도 범위내에 존재하는 것을 확인하였다.

• 한국환경복원기술학회지
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• 제10권6호
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• pp.15-32
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• 2007

The purposes of this study are carrying out the case study for the urban park planning in point of landscape ecology, analyzing and evaluating the indicator character of the landscape ecological view on the basis of the case study, and proposing the urban park planning in point of landscape ecology. The results of this study are as follows. As a result of the isolation analysis with school green space, Kyukchaebosang Park turned out to be 607m, Chimsan Park to be the highest 647.14m, Ehyeun Park to be the lowest 592m. In the case of connection analysis with all nodes, Kyukchaebosang Park had the lowest score 0.27 and Chimsan Park had the highest score 1. As a result of the circulation analysis with elementary schools, Kyukchaebosang Park and Ehyeun Park got 1 within 500m permissible range, and Chimsan Park got over 1, Ehyeun Park got 0.67, and Kyukchaebosang Park got 0.14 respectively within 700m permissible range. According to these analysis results, special regions which has problems such as high isolation and low connection and circulation in point of landscape ecology can be selected. Also by changing them to valuable green spaces, urban park planning can be improved. In this study, the basic data of landscape ecology can be obtained by the character analysis of landscape ecology. This study has a significant meaning of possibility in planning of the urban park which reflects the character of landscape ecology. This research was only performed in Chimsan Park, so additional researches for various cases will be needed.

• 식품보건융합연구
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• 제6권1호
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• pp.21-27
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• 2020

The levels of five heavy metals (mercury, cadmium, lead, copper and zinc) were analyzed in edible tissues of Lophius piscatorius Linnaeus, 1758 marketed in Sinop coasts of the Black Sea by using inductively coupled plasma mass spectrometry. With the present study, heavy metal values of this fish in the Black Sea were examined for the first time. The mean concentrations in mg kg^-1 wet wt. of Hg, Cd, Pb, Cu and Zn were 0.022, 0.009, 0.035, 6.3 and 16 mg kg^-1 wet wt., respectively. The results of the present study indicate that the consumption of muscle from anglerfish can be considered safe in terms of permissible legal limits. It is clear that, Zn showed the high accumulation in muscle tissue followed by Cu, while non-essential metals Hg, Cd and Pb showed the low accumulation. This could be explained by the fact that Zn and Cu are essential elements in the bodies of living organisms and has an important role in different physiological processes. In the present study, heavy metal levels in angler fish were low. Likewise, the calculated HI values were lower than one. In conclusion, the results of the present study indicate that the consumption of muscle from anglerfish can be considered safe in terms of permissible legal limits and hazard index values.

• The Korean Journal of Pain
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• 제25권1호
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• pp.16-21
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• 2012

Background: The C-arm fluoroscope is known as the most important equipment in pain interventions. This study was conducted to investigate the completion rate of education on radiation safety, the knowledge of radiation exposure, the use of radiation protection, and so on. Methods: Unsigned questionnaires were collected from the 27 pain physicians who applied for the final test to become an expert in pain medicine in 2011. The survey was composed of 12 questions about the position of the hospital, the kind of hospital, the use of C-arm fluoroscopy, radiation safety education, knowledge of annual permissible radiation dose, use of radiation protection, and efforts to reduce radiation exposure. Results: In this study, although most respondents (93%) had used C-arm fluoroscopy, only 33% of the physicians completed radiation safety education. Even though nine (33%) had received education on radiation safety, none of the physicians knew the annual permissible radiation dose. In comparing the radiation safety education group and the no-education group, the rate of wearing radiation-protective glasses or goggles and the use of radiation badges or dosimeters were significantly higher in the education group. However, in the use of other protective equipment, knowledge of radiation safety, and efforts to reduce radiation exposure, there were no statistical differences between the two groups. Conclusions: The respondents knew very little about radiation safety and had low interest in their radiation exposure. To make the use of fluoroscopy safer, additional education, as well as attention to and knowledge of practices of radiation safety are required for pain physicians.