• Title/Summary/Keyword: system lifetime

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Power-efficiency Analysis of the MIMO-VLC System considering Dimming Control (조광제어를 고려한 MIMO-VLC 시스템의 전력 효율 분석)

  • Kim, Yong-Won;Lee, Byung-Jin;Lee, Byung-Hoon;Lee, Min-Jung;Kim, Kyung-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.6
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    • pp.169-180
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    • 2018
  • White light-emitting diodes (LEDs) are more economical than fluorescent lights, and provide high brightness, a high lifetime expectancy, and greater durability. As LEDs are closely connected with people's daily lives, dimming control of LED is an important component in providing energy savings and improving quality of life. In visible light communications systems using these LEDs, multiple input multiple output (MIMO) technology has attracted a lot of attention, in that it can attain the channel capacity in proportion to the number of antennas. This paper analyzes the power performance of three kinds of modulation in visible light communications (VLC) systems applied space-time block code (STBC) techniques. The modulation schemes are return-to-zero on-off keying (RZ-OOK), variable pulse position modulation (VPPM), and overlapping pulse position modulation (OPPM), and dimming control was applied. The power requirements and power consumption were used as metrics to compare the power efficiency in $2{\times}2$ STBC-VLC environments under the three kinds of modulation. We confirm that dimming control affects the communications performance of each modulation scheme. VPPM showed greater consumption among the three modulations, and OPPM showed energy savings comparable to VPPM.

A study on Keup-ahm Min Sah-pyeong's Realization of Reality (급암(及庵) 민사평(閔思平)의 현실인식)

  • Jeong, Seong-sik
    • (The)Study of the Eastern Classic
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    • no.69
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    • pp.509-530
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    • 2017
  • The purpose f this thesis is to examine the reality of Min Sha-pyeong, which led to life in the end of the Koryo Dynasty. Min Sha-pyeong was able to conduct academic exchanges through active negotiations with various scholars at the time. After passing the civil service exam at the age of 21, Min Sha-pyeong acted in various positions and remained loyal to the government. Min Sha-pyeong, who frequently met with Lee Je-hyun, Baek Mun-bo and Lee-saek, exchanged opinions. Sometimes Baek Mun-bo gathered together and always joined him when drinking. Lee-saek was convinced that his poetry would continue to inspire. The time when Min Sha-pyeong was active very confusing at home and abroad. In the end of the Koryo Dynasty, the national operating system was unstable due to the poor land and the suffering of the afflicted people, who suffered from frequent in vasions of Japan. At the time, the corruption and the suffering of the people were serious. Min Sha-pyeong refers to the reality of the people who love the people, reflecting the lives of the people living in poverty. Min Sha-pyeong thinks life without loyality is not a normal life. If I had a desire, I realized that the riches of wealth would wane someday. Min Sha-pyeong hoped that he would be relieved of his sympathy and would be relieved of their position in sympathy ith the people. Here, youy can see the reality of the people in Min Sha-pyeong is clearly revealed.

Policies and Measures for Managing Personal Digital Legacy (개인의 사후 디지털 기록관리를 위한 정책과 방안)

  • Kim, Jinhong;Rieh, Hae-young
    • The Korean Journal of Archival Studies
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    • no.72
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    • pp.165-203
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    • 2022
  • Many people create records in digital space, and the amount of digital records left after individual dies has increased. The digital record left by the deceased is different from the record heritage that has physical substances. In many cases, the records of the deceased not just belong to the deceased, and many deceased did not explicitly disclose their online accounts and method of dispose of digital records during their lifetime, so this problem may lead to problems of inheritance to the bereaved family. In addition, digital records may be neglected or deleted after a person's death due to software problems, specific platform's terms of use, account deletion by bereaved family, etc. This leads to the problem that daily records, which are important clues to the social aspects at the time, are easily lost. Several studies have revealed that individuals are interested in preserving their digital records, but do not know how to do it, so they are benign neglect. For this reason, it is necessary to pay attention to personal digital records and personal digital legacy, and to prepare related policies and plans. Accordingly, this study analyzes problems related to the management of digital records after an individual's death, related to laws and systems, the status and policies of platforms and industries, the status of personal record management, etc. Various solutions were suggested, such as a need for enactment for digital personal record management act, platform's explicit policy for individual's post-mortem records, digital records management plan for archival institutions, individual's a preemptive management plan for his/her own records, and a method for writing a will related to digital account information.

Growth Behavior of Heteroepitaxial β-Ga2O3 Thin Films According to the Sapphire Substrate Position in the Hot Zone of the Mist Chemical Vapor Deposition System (미스트화학기상증착 시스템의 Hot Zone 내 사파이어 기판 위치에 따른 β-Ga2O3 이종 박막 성장 거동 연구)

  • Kyoung-Ho Kim;Heesoo Lee;Yun-Ji Shin;Seong-Min Jeong;Si-Young Bae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.5
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    • pp.500-504
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    • 2023
  • In this study, the heteroepitaxial thin film growth of β-Ga2O3 was studied according to the position of the susceptor in mist-CVD. The position of the susceptor and substrate was moved step by step from the center of the hot zone to the inlet of mist in the range of 0~50 mm. It was confirmed that the average thickness increased to 292 nm (D1), 521 nm (D2), and 580 nm (D3) as the position of the susceptor moved away from the center of the hot zone region. The thickness of the lower region of the substrate is increased compared to the upper region. The surface roughness of the lower region of the substrate also increased because the nucleation density increased due to the increase in the lifetime of the mist droplets and the increased mist density. Therefore, thin film growth of β-Ga2O3 in mist-CVD is performed by appropriately adjusting the position of the susceptor (or substrate) in consideration of the mist velocity, evaporation amount, and temperature difference with the substrate, thereby determining the crystallinity of the thin film, the thickness distribution, and the thickness of the thin film. Therefore, these results can provide insights for optimizing the mist-CVD process and producing high-quality β-Ga2O3 thin films for various optical and electronic applications.

A Study on the Food-culture's Property of the Traditional Generation through the Oral Interview (구술을 통한 전통세대의 음식문화특성 연구)

  • Kim, Mi-Hye;Chung, Hae-Kyung
    • Journal of the Korean Society of Food Culture
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    • v.24 no.6
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    • pp.613-630
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    • 2009
  • This thesis, which involves honest life stories of members of the ìtraditionalî Korean generation that lived through the turbulent times of the first half of the twentieth century, assesses the meaning and import of Korean cuisine during an individual Korean's lifetime, as well as the relevant properties of the culinary culture of the traditional generation and how those properties continue to influence the present generation of Koreans. Thus, traditional Korean culinary culture was subdivided into the following four aspects, each of which were exemplified by representative examples. The first of these is slow-food dietary life, which is exemplified by fermented foods. The development of side dishes (panchan) based on fermentation - kimchi, different types of soy and bean paste, salted seafoods, dishes of dried radish or cucumber slices seasoned with soy sauce, and so on - made the quantitative and qualitative supplementation of food possible for traditional Koreans. The second of these aspects, referred to as friendly dietary life, is exemplified by self-sufficiently produced foods. The system of many species and small production suitable with the season made it possible to produce food from sustainable ecological systems and to maintain locally grown food-cultures, each of which was distinguished from others by a local specialty product. The third aspect of the traditional Korean culinary culture involves the same use of medicinal roots and plant materials for foodstuff, and this is exemplified by the use of foods to cure and prevent diseases. The notion, for example, that 'boiled rice is an invigorant' is characteristic of the notion that diet can function in a preventative medical context, and other similar Korean notions illustrate the importance, also, of the curative properties of food. The fourth and final aspect of traditional Korean culinary culture identified herein is creative dietary life, which can be viewed essentially as a Korean adaptation to the turbulence of life during the early $20^{th}$ century in Korea. This trend is exemplified by many Korean foods that were created in response to foreign influences, such as onions, cabbages, curry, etc. which found their place in overall Korean culture through the age of Japanese settlement, as well as the Korean war.

Assessment of natural radioactivity in soil and olive mill pomace utilizing nal (TI) gamma-ray spectrometry and low background alpha/beta counting system

  • Amani Kraishan;Mohammad Abu Shayeb;Hafedh Belmabrouk;Ahmad Ali Husein Qwasmeh;Muzahir Ali Baloch
    • Nuclear Engineering and Technology
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    • v.56 no.5
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    • pp.1925-1931
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    • 2024
  • The study conducted in the northwest region of Jordan aimed to assess the levels of natural radioactivity in soil and olive mill pomace (OMP) samples. The researchers used Nal (TI) gamma-ray spectrometry to measure the activity concentrations of 226Ra, 232Th, 40K, and 137Cs in the samples. The average activity concentrations of 226Ra, 232Th, 40K, and 137Cs in the soil samples were found to be 18.624 ± 5.82, 12.276 ± 5.728, 518.33 ± 212.57, and 0.140 ± 0.09 (Bq, kg-1), respectively. In the OMP samples, the average activity concentrations of 226Ra, 232Th, and 40K were 7.272 ± 4.386, 3.454 ± 1.503, and 169.997 ± 81.873 (Bq kg-1), respectively, and no 137Cs was detected. The study also investigated fundamental parameters associated with radon, specifically the radon emanation coefficient (RnEC) and radon mass exhalation rate (Ex). The RnEC values ranged from 0.621 to 0.78 (Bq kg-1), with an average value of 0.71 ± 0.06 (Bq kg-1). The estimated Ex from the soil samples ranged from 65.83 to 124.86 (mBq kg-1h-1), with an average value of 99.74 ± 21.73 (mBq kg-1h-1). Regarding radiological hazards, the study examined various parameters, including radium equivalent activity, external and internal hazard indices, gamma and alpha indices, absorbed gamma dose rate, and excess lifetime cancer risk. All of these assessed values were found to be below the worldwide recommended limits for radiological safety. Additionally, the study analyzed the concentrations of gross alpha and gross beta radioactivities in soil and OMP samples. The soil samples had an average gross alpha activity of 4.642 ± 1.04 (Bq kg-1) and an average gross beta activity of 48.13 ± 14.50 (Bq kg-1). The OMP samples showed an average gross alpha activity of 0.32 ± 0.27 (Bq kg-1) and an average gross beta activity of 59.19 ± 12.94 (Bq kg-1). Overall, the obtained results are crucial for evaluating the radiological risks associated with natural radioactivity in the northwest region of Jordan. The findings establish baseline data for comparison and reference for radioactivity levels in the environment.

A Case Study on Nongak and Dangsanje as Regional Sources of Influence on the Formation of Jeungsan Thought: Focused on Jeongeup City, Jeonbuk-do Province (증산사상(甑山思想) 형성에 미친 지역적 영향원(影響源)으로서의 농악·당산제에 관한 사례적 고찰 -정읍지역을 중심으로-)

  • Heo Jeong-joo
    • Journal of the Daesoon Academy of Sciences
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    • v.49
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    • pp.127-156
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    • 2024
  • The purpose of this study is to examine the influence of the village gut (shamanic ritual) Dangsanje and Nong-ak (agricultural musical ritual) in the Jeong-eup Province on the formation of the ideology of the Jeungsan (甑山), Kang Il-sun (姜一淳 1871~1909), a thinker from Jeong-eup. As a result, this article has reached the following conclusions: first, the ideas of a certain thinker are influenced by the local culture in which they were born and raised. Second, the central area where Kang Jeungsan was born, grew up, and later developed his system of philosophical thought was the Jeong-eup Province. Third, in Jeong-eup, Nong-ak is traditionally accompanied as a necessary requirement. Fourth, the Nong-ak that Kang Jeungsan witnessed in his hometown during his lifetime had those qualities. Fifth, Kang Jeungsan empirically identified the close interrelationship between Village Gut Dangsanje, Nong-ak, and Mudanggut from an early age. Sixth, this aspect of influence is tangibly reflected in the words and actions he left behind. Seventh, Kang Jeungsan's experience of Jeong-eup Nong-ak was recreated in the religious music of Bocheonism, where his ideas were formulated into an organized religion for the first time. Eighth, this process of religionizing Nong-ak in Bocheonism greatly influenced later Jeong-eup Nong-ak and also Honam Nong-ak more generally.

A study on the developing and implementation of the Cyber University (가상대학 구현에 관한 연구)

  • Choi, Sung;Yoo, Gab-Sang
    • Proceedings of the Technology Innovation Conference
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    • 1998.06a
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    • pp.116-127
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    • 1998
  • The Necessity of Cyber University. Within the rapidly changing environment of global economics, the environment of higher education in the universities, also, has been, encountering various changes. Popularization on higher education related to 1lifetime education system, putting emphasis on the productivity of education services and the acquisition of competitiveness through the market of open education, the breakdown of the ivory tower and the Multiversitization of universities, importance of obtaining information in the universities, and cooperation between domestic and oversea universities, industry and educational system must be acquired. Therefore, in order to adequately cope wi th these kinds of rapid changes in the education environment, operating Cyber University by utilizing various information technologies and its fixations such as Internet, E-mail, CD-ROMs, Interact ive Video Networks (Video Conferencing, Video on Demand), TV, Cable etc., which has no time or location limitation, is needed. Using informal ion and telecommunication technologies, especially the Internet is expected to Or ing about many changes in the social, economics and educational area. Among the many changes scholars have predicted, the development and fixations of Distant Learning or Cyber University was the most dominant factor. In the case of U. S. A., Cyber University has already been established and in under operation by the Federate Governments of 13 states. Any other universities (around 500 universities has been opened until1 now), with the help of the government and private citizens have been able to partly operate the Cyber University and is planning on enlarging step-by-step in the future. It could be seen not only as U. S. A. trying to elevate its higher education through their leading information technologies, but also could be seen as their objective in putting efforts on subordinating the culture of the education worldwide. UTRA University in U. S. A., for example, is already exporting its class lectures to China, and Indonesia regions. Influenced by the Cyber University current in the U.S., the Universities in Korea is willing .to arrange various forms of Cyber Universities. In line with this, at JUNAM National University, internet based Cyber University, which has set about its work on July of 1997, is in the state of operating about 100 Cyber Universities. Also, in the case of Hanam University, the Distant Learning classes are at its final stage of being established; this is a link in the rapid speed project of setting an example by the Korean Government. In addition, the department of education has selected 5 universities, including Seoul Cyber Design University for experimentation and is in the stage of strategic operation. Over 100 universities in Korea are speeding up its preparation for operating Cyber University. This form of Distant Learning goes beyond the walls of universities and is in the trend of being diffused in business areas or in various training programs of financial organizations and more. Here, in the hope that this material would some what be of help to other Universities which are preparing for Cyber University, I would 1ike to introduce some general concepts of the components forming Cyber University and Open Education System which has been established by JUNAM University. System of Cyber University could be seen as a general solution offered by tile computer technologies for the management on the students, Lectures On Demand, real hour based and satellite classes, media product ion lab for the production of the multimedia Contents, electronic library, the Groupware enabling exchange of information between students and professors. Arranging general concepts of components in the aspect of Cyber University and Open Education, it would be expressed in the form of the establishment of Cyber University and the service of Open Education as can be seen in the diagram below.

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Strategies for Public Health Service Development in the Times of Local Autonomy (지방자치시대의 공공보건사업 발전 전략)

  • 박정한
    • Health Policy and Management
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    • v.12 no.3
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    • pp.1-22
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    • 2002
  • Health is a fundamental human right and a sine qua non for happiness of people and for national development. Government has a responsibility for the provision of health services for their people. Recent changes of disease pattern, i.e. decrease of Infectious diseases and increase of chronic and degenerative diseases Including cancer and cardiovascular diseases, together with universal coverage of health insurance and improved living standard have prompted medical care utilization and skyrocketed the national health expenses. The goal of national health policy is improving the quality of life through the betterment of health level. To achieve this goal it is necessary to establish a healthcare system for lifetime, to improve the efficiency of healthcare delivery system, and to strengthen the public health services for disease prevention and health promotion. The current public health service programs are Inefficient due to an inconsistent policy for health service program, lack of health information system, irrational health program planning and evaluation, and Inadequate training of health workers. Local government has a legal responsibility for health service program planning and promoting the competence of health workers. Thus, municipal and provincial health departments should expand their roles and strengthen their function. The strategies for developing public health service programs at local level are ${\circled}1$ stipulating the goals of health policy, ${\circled}2$ promoting the ability for health program planning and evaluation, ${\circled}3$ establishing health information and surveillance system, ${\circled}4$ training of health workers, ${\circled}5$ establishing an institution for health information management and training of health workers, and ${\circled}61$ collaboration with local universities.

Economic analysis of Frequency Regulation Battery Energy Storage System for Czech combined heat & power plant (체코 열병합발전소 주파수조정용 배터리에너지저장장치 경제성 분석)

  • KIM, YuTack;Cha, DongMin;Jung, SooAn;Son, SangHak
    • Journal of Energy Engineering
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    • v.29 no.2
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    • pp.68-78
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    • 2020
  • According to the new climate change agreement, technology development to reduce greenhouse gases is actively conducted worldwide, and research on energy efficiency improvement in the field of power generation and transmission and distribution is underway [1,2]. Economic analysis of the operation method of storing and supplying surplus electricity using energy storage devices, and using energy storage devices as a frequency adjustment reserve power in regional cogeneration plants has been reported as the most profitable operation method [3-7]. Therefore, this study conducted an economic analysis for the installation of energy storage devices in the combined heat and power plant in the Czech Republic. The most important factor in evaluating the economics of battery energy storage devices is the lifespan, and the warranty life is generally 10 to 15 years, based on charging and discharging once a day. For the simulation, the ratio of battery and PCS was designed as 1: 1 and 1: 2. In general, the primary frequency control is designed as 1: 4, but considering the characteristics of the cogeneration plant, it is set at a ratio of up to 1: 2, and the capacity is simulated at 1MW to 10MW and 2MWh to 20MWh according to each ratio. Therefore, life was evaluated based on the number of cycles per year. In the case of installing a battery energy storage system in a combined heat and power plant in the Czech Republic, the payback period of 3MW / 3MWh is more favorable than 5MW / 5MWh, considering the local infrastructure and power market. It is estimated to be about 3 years or 5 years from the simple payback period considering the estimated purchase price without subsidies. If you lower the purchase price by 50%, the purchase cost is an important part of the cost for the entire lifetime, so the payback period is about half as short. It can be, but it is impossible to secure profitability through the economy at the scale of 3MWh and 5MWh. If the price of the electricity market falls by 50%, the payback period will be three years longer in P1 mode and two years longer in P2 and P3 modes.