• Title/Summary/Keyword: over current characteristics

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Feasibility Analysis on Replacing LED Lighting with Incandescent Bulbs in Public Institution (백열 전구의 LED 조명 교체에 대한 타당성 분석 - 공공기관을 중심으로 -)

  • Park, Youn Mi;Lee, Myung Koon
    • Journal of Climate Change Research
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    • v.1 no.3
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    • pp.205-210
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    • 2010
  • LED light has various advantages such as an energy saving effect of over 80% compared to existing lighting and environmentally friendly characteristics; however, there has been no affordable market for LED lighting because of its expensive price. This study discussed the validity of the expansion of distribution of LED lighting through an assessment of economic efficiency concerning LED lightening in order to analyze its efficiency in terms of energy savings and maintenance and repair, which will be generated as a result of the change from existing incandescent bulbs to LED lighting in the public sector. As to the target of analysis, the paper reviewed the validity of change to LED lighting as a result of the elimination of existing incandescent bulbs, by referring to 'the current incandescent bulb use and elimination performance' published by the Ministry of Knowledge Economy based on the "Elimination management system" executed by Korea Energy Management Corporation. The paper considered expenses for change, annual power savings amount and electric charges savings amount, repair and maintenance cost, $CO_2$ reduction volume, and the profit from the sale of CER (certified emission reduction). As a result of analyzing economic efficiency, when the discount rate during the change of existing incandescent bulb lighting to LED lighting is 3.26%, the profit was 8,648,400,000 won. Accordingly, NPV was analyzed to have a 'positive (+)' value, which means that this change is profitable.

A Study on Estimating Ship Emission - Focusing on Gwangyang Port and Ulsan Port (선박에 기인한 대기오염물질 배출량 산정 연구 -광양항과 울산항을 중심으로)

  • Zhao, Ting-Ting;Yun, Kyong-Jun;Lee, Hyang-Sook
    • Journal of Korea Port Economic Association
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    • v.35 no.2
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    • pp.93-108
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    • 2019
  • Recently, air pollution from the marine ports has become a serious issue all over the world. Because marine trade accounts for 99.7% of Korea's trade, efforts are required to recognize the level of port pollution and establish environmental policies. This study estimates air pollution emitted during the berthing process in the Gwangyang and Ulsan ports. Data on ship activity and characteristics are collected and reasonable methodologies and factors from EEA and EPA are adopted. The results show that 253.09 tons of CO, 1986.61 tons of NOx, 684.01 tons of SOx, 47.88 tons of $PM_{10}$, and 44.69 tons of $PM_{2.5}$ are emitted at the Gwangyang port. Further, the Ulsan port emitted 212.28 tons of CO, 1712.54 tons of NOx, 573.72 tons of SOx, 40.16 tons of $PM_{10}$, and 37.48 tons of $PM_{2.5}$. A stage-by-stage plan for installing AMP infrastructure is suggested as part of a green port policy. This research provides the current pollution status and contributes guidelines for the direction of future policy.

Development of a High Performance Ocean Model using Julia Language (줄리아 언어를 이용한 고성능 해양모델의 개발)

  • KWON, MIN-SUN;KIM, JONG GU
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.24 no.2
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    • pp.187-207
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    • 2019
  • In order to develop a high performance ocean model, we used Julia, a Just-In-Time compile language, and to obtain the solution of the momentum equation, we made the code to solve the Poisson equation by the Successive Over-Relaxation method. And then we made two models to test Julia calculation codes. First, a simple channel form is modeled to test constant source/sink conditions. Second, the simplified Yellow Sea was modeled to test tidal forcing, Coriolis forces, and the effect of vertical eddy diffusivity coefficients. The model has been tested with a total of eight cases in the two scenarios. As a result of the test, the depth-averaged current speed of the three cases in Scenario 1 converged perfectly to the theoretical value, and that showed well a vertical flow velocity gradient due to the bottom friction. Also, the result of Scenario 2 represented well the amphidromic points of Yellow Sea and the tidal characteristics of mid-western and southwestern coast of Korea. Therefore, it is considered that the ocean model using Julia language has developed successfully, this suggests that the ocean model has come to the stage of successful transition from a classical compile language to a Just-In-Time compile language.

A Comparative Study of Block Chain : Bitcoin·Namecoin·MediBloc (블록체인 비교연구: 비트코인·네임코인·메디블록)

  • Kim, Ji Yeon
    • Journal of Science and Technology Studies
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    • v.18 no.3
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    • pp.217-255
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    • 2018
  • Bitcoin, which appeared in 2008, was merely a conceptual virtual currency, but it now enjoys the status as actual money. Bitcoin is an electronic money system that can be traded directly without a central trust institution. Thanks to the popularization of Bitcoin, blockchain technology has become a widespread concern. That technology is expanding not only the currency mechanism, but also a variety of other services. The possibility of a blockchain in relation to actual currency is ongoing. This paper investigates the technological characteristics and social construction of the blockchain by comparing the cases of Bitcoin, Namecoin, and MediBloc among blockchain applications. Namecoin emerged in 2013 is an attempt to replace the centralized Internet Domain Name System(DNS). There has been controversy over that current system for a long time, but replacing the already established system is not easy. Nevertheless, Namecoin has potential as an alternative. Meanwhile, MediBloc is an application that involves distributed management of medical data in South Korea. MediBloc claims that the key producers of medical data are patients themselves. This is to challenge to the question who is a knowledge producer of medical data. Through these three cases, it has discussed that blockchain technology does supports to form more democratic decision-making or simply provide a technical solution as automation. As a citizen, we can intervene in the realization of blockchains by presenting social agenda. This will be a method of the social construction of technology.

A Study on the Synthesis and Electrochemical Characteristics of Carbonized Coffee Powder for Use as a Lithium-Ion Battery Anode (리튬 이온 이차전지 음극 활물질용 탄화 커피 분말 제조 및 전기화학적인 특성연구)

  • Kim, Tae Gyun;Cho, Jin Hyuk;Pham-Cong, De;Jeon, Injun;Hwang, Jin Hyun;Kim, Kyoung Hwa;Cho, Chae Ryong
    • New Physics: Sae Mulli
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    • v.68 no.12
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    • pp.1315-1323
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    • 2018
  • We studied the carbonization due to the annealing condition of waste coffee powder for application as an active anode material for lithium-ion batteries (LIBs). The coffee powder used as an active anode material for LIBs was obtained from coffee beans, not from a coffee shells. The waste coffee powder was dried in air and heat-treated in an $Ar/H_2$ atmosphere to obtain a pore-forming activated carbon powder. The specific capacity of the sample annealed at $700^{\circ}C$ was still 303 mAh/g after 1000 cycles at a current density of 1000 mA/g and with a coulombic efficiency of over 99.5%. The number of pores and the pore size of the waste coffee powder were increased due to chemical treatment with KOH, which had the some effect as an increased specific surface area. The waste coffee powder is considered to be a very promising active anode material because of both its excellent electrochemical properties due to enhanced carrier conduction and its being a cost effective resource for use in LIBs.

A Study on Non-Standardization of Government-Supported Research Institutes : A Case of Non-Standard Workers in GSRI in Deajeon Area (정부출연연구기관의 연구인력 비정규직화에 관한 연구 : 대전지역 과학기술분야 정부출연연 비정규직 연구노동자 사례를 중심으로)

  • Choi, In-Yi
    • Korean Journal of Labor Studies
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    • v.23 no.1
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    • pp.85-127
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    • 2017
  • Due to the management innovation policy that was introduced to governmentsupported research institutes (GSRI) in 1998, their employment structure has been continuously changing, with the most notable increase of the number of non-standard researchers and the diversification of employment contracts. This paper examines changes in the employment structure of GSRI over the last 20 years in relation to the introduction and operation of the PBS (project base system), which is a main factor that fundamentally changed the employment structure of research institutes. This paper purposes to analyze the current status of non-standard workers in the science and technology research area through interviewing standard and non-standard researchers. Under the PBS as a principle of organizing their research project, the project-managers cannot help but exploit non-standard researchers to process research within a tight budget. This structure of organizing research projects reinforces the increase of the number of non-standard researchers and diversification of non-standard employment relations. In addition, the wage and working conditions of non-standard workers are getting aggravated in this structure. Considering the characteristics of research institutes, precarious status of non-standard researchers will have negative effects on the development of science and technology.

Predictors of Breastfeeding in Adult Women: a Secondary Data Analysis of The Seventh Korea National Health and Nutrition Examination Survey(KNHANES VII-3), 2018 (성인 여성의 모유수유 예측요인: 국민건강영양조사 제7기 3차년도(2018)의 2차 자료 분석)

  • Seong, Ji-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.12
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    • pp.440-448
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    • 2020
  • This study was conducted to identify the factors affecting breastfeeding in adult women based on socio-demographic and health-related characteristics using the results of KNHANES VII-3. The data was analyzed by applying weights, using the complex sample analysis method of the SPSS Win 22.0 program. Breastfeeding was influenced significantly by age, education level, and the current smoking status. Women in the age group of 30-39 years had a breastfeeding rate that was 3.06 times higher than 19-29 year old women. Also, the breastfeeding rates for women with an education level under elementary school were 4.70 times higher than those with a college degree or higher education level and non-smokers and ex-smokers had levels 2.51 times higher than smokers. Therefore, for mothers under the age of 30, education on breastfeeding should be further strengthened. For mothers over 40 years old, lactation support to increase the milk supply should be provided as well as assistance toward care for other children in the family. Also, better-educated mothers will need to learn effective breastfeeding methods in limited environments such as work-life, and a social atmosphere needs to be established that is considerate to lactating women. Furthermore, education related to pregnancy and lactation should be provided for use in smoking cessation programs for female smokers.

Elementary and Secondary School Teachers' Polar Literacy (초·중등학교 교사들의 극지 소양)

  • Chung, Sueim;Choi, Haneul;Kim, Minjee;Shin, Donghee
    • Journal of the Korean earth science society
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    • v.42 no.6
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    • pp.734-751
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    • 2021
  • The purpose of this study is to prepare basic data to reflect polar literacy education in the school curriculum. The perception about the polar regions, teaching experience, and polar-related cognitive and affective characteristics of teachers were investigated. The survey was conducted among 56 elementary, middle, and high school teachers from schools from 10 major cities and surrounding regions, based on their perceptions of the polar region, current teaching status, polar knowledge, and beliefs and attitudes toward polar region and climate change. Results showed that although teachers' polar information efficacy was low, they positively evaluated the status of educators in resolving polar and climate change problems, and prioritized global citizenship values over practical purposes. The experience of teaching polar region and climate change issues at schools varied across subjects and non-subjects, but showed a passive aspect in teaching development, such as wanting to be provided with consolidated learning materials. On the cognitive aspect, teachers revealed an ambiguous understanding of the mechanisms and processes by which polar change and climate influence each other. On the affective aspect, most teachers showed strong beliefs and attitudes for polar-related issues beyond the school level, but their behavior choices were relatively lower. Based on the results, we propose the following as recommendations: providing opportunities and materials to promote polar knowledge, discovering educational materials in various contexts to form values and attitudes, developing educational materials from polar research materials, identifying misconceptions about polar knowledge among students and teachers, strengthening elementary school teachers' polar literacy, and cultivating positive attitudes and values toward polar issues.

Development of a Acoustic Acquisition Prototype device and System Modules for Fire Detection in the Underground Utility Tunnel (지하 공동구 화재재난 감지를 위한 음향수집 프로토타입 장치 및 시스템 모듈 개발)

  • Lee, Byung-Jin;Park, Chul-Woo;Lee, Mi-Suk;Jung, Woo-Sug
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.22 no.5
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    • pp.7-15
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    • 2022
  • Since the direct and indirect damage caused by the fire in the underground utility tunnel will cause great damage to society as a whole, it is necessary to make efforts to prevent and control it in advance. The most of the fires that occur in cables are caused by short circuits, earth leakage, ignition due to over-current, overheating of conductor connections, and ignition due to sparks caused by breakdown of insulators. In order to find the cause of fire at an early stage due to the characteristics of the underground utility tunnel and to prevent disasters and safety accidents, we are constantly managing it with a detection system using image analysis and making efforts. Among them, a case of developing a fire detection system using CCTV-based deep learning image analysis technology has been reported. However, CCTV needs to be supplemented because there are blind spots. Therefore, we would like to develop a high-performance acoustic-based deep learning model that can prevent fire by detecting the spark sound before spark occurs. In this study, we propose a method that can collect sound in underground utility tunnel environments using microphone sensor through development and experiment of prototype module. After arranging an acoustic sensor in the underground utility tunnel with a lot of condensation, it verifies whether data can be collected in real time without malfunction.

Deriving AR Technologies and Contents to Establish a Safety Management System in Railway Infrastructure (철도 인프라 안전 관리 시스템 구축을 위한 AR 기술 및 콘텐츠 도출)

  • Jeon, Hae-In;Yu, Young-Su;Koo, Bon-Sang;Seo, Hyeong-Lyel;Kim, Ji-Hwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.3
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    • pp.427-438
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    • 2022
  • With the recent growing importance over safety management the need for advanced and technical approaches for on-site safety inspection methods has increased. Railway construction is subject to its own particular set of temporal and spatial challenges due to its unique facilities and equipment. This study aimed to investigate the field characteristics of railway infrastructure and improve the conventional field safety management methods by identifying the most appropriate features of AR technology. Group interviews and surveys were conducted with field safety experts to derive the major problems and inspection needs. Subsequently, various features of AR, such as BIM model projection, and remote conferencing, were investigated to determine their applicability to address safety issues. As a result, four problems in the current safety management process, such as 'lack of time due to the conventional inspection method and inspection of areas that are difficult to access', and three major inspection types, such as 'observance of work procedures, status of installation, adequate dimensional spacing', were identified to be improved when adopting AR based techniques. Furthermore, AR technology utilizing plans to solve safety inspection problems and effectively manage major inspection types were proposed, and a follow up survey was conducted with the same field safety experts to derive the priority of technology development.