• Title/Summary/Keyword: slowdown

Search Result 129, Processing Time 0.022 seconds

Partial Fault Detection of an Air-conditioning System by using a Moving Average Neural Network

  • Han, Do-Young;Lee, Han-Hong
    • International Journal of Air-Conditioning and Refrigeration
    • /
    • v.11 no.3
    • /
    • pp.125-131
    • /
    • 2003
  • The fault detection and diagnosis technology may be applied in order to decrease the energy consumption and the maintenance cost of the air-conditioning system. In this paper, two fault detection methods were considered. One is a generic neural network, and the other is an moving average neural network. In order to compare the performance of fault detection results from these methods, two different types of faults in an air-conditioning system were applied. These are the condenser 30% fouling and the evaporator fan 25% slowdown. Test results showed that the moving average neural network was more effective for the detection of partial faults in the air-conditioning system.

Partial Fault Detection of Air-conditioning System by Neural Network Algorithm using Data Preprocessing Method (데이터 전처리기법을 적용한 신경망 알고리즘의 냉방기 부분고장 검출)

  • 한도영;이한홍;윤태훈
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.14 no.7
    • /
    • pp.560-566
    • /
    • 2002
  • The fault detection and diagnosis technology may be applied in order to decrease the energy consumption and the maintenance cost of the air-conditioning system. In this study, two different types of faults in the air-conditioning system, such as the condenser fouling and the evaporator fan slowdown, were considered. The neural network algorithm combined with data preprocessor was developed and applied to detect the faults of the real system. Test results show that this method is very effective to detect the faults in the air-conditioning system. Therefore, this developed method can be used for the development of the air-conditioner fault detection system.

Bar Formation and Evolution in Disk Galaxies with Classical Bulges

  • Seo, Woo-Young;Kim, Woong-Tae
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.44 no.2
    • /
    • pp.37.2-37.2
    • /
    • 2019
  • To study the effects of central mass concentration on the formation and evolution of galactic bars, we run fully self-consistent simulations of Milky Way-sized, isolated galaxies with initial classical bulges. We let the mass of a classical bulge mass less than 20% of the total disk mass, and vary the central concentration of a dark matter halo. We find that both classical bulge and halo concentration delay the bar formation and weaken the bar strength. The presence of a bulge increases the initial rotational velocity near the center and hence the bar pattern speed. Bars in galaxies with a more concentrated halo slowdown relatively rapidly as they lose their angular momentum through interaction with the halo. In some of our models, bars do not experience slowdown at the expense of the decrease in their moment of inertia as the bar evolves, with the resulting pattern speed similar to that of the bar in the Milky Way.

  • PDF

China's Slowdown

  • BARRY EICHENGREEN
    • KDI Journal of Economic Policy
    • /
    • v.46 no.1
    • /
    • pp.1-19
    • /
    • 2024
  • This paper evaluates explanations for China's growth slowdown. The natural tendency for rapidly growing economies to slow down is a major factor, along with problems bequeathed by unbalanced growth, including a declining ICOR, slowing total factor productivity growth, and rising indebtedness. A number of other mechanisms are of lesser importance: demographics, President Xi's centralization of political power and anti-corruption campaign, and U.S. export controls. Sustaining growth in the longer term will require China to step away from investment, debt and export-fueled growth in favor of a balanced growth model with household consumption playing a larger role. Doing so will require hardening of the budget constraints of regional and local governments and restructuring of the nonperforming debts of property and construction companies.

The Favorable Synoptic Patterns of Heat Waves in Korea

  • Park, Gwangyong;Park, Jongnam
    • Proceedings of the KGS Conference
    • /
    • 2003.05a
    • /
    • pp.83-86
    • /
    • 2003
  • Hot environment can cause unseen economic loss by slowdown of human activities owing to the accumulation of heat stress. The attack of a strong heat wave to the highly populated urban areas was even evaluated to result in the more fatal damages than any other natural disaster such as flooding or blizzards (Changnon et al, 1996). (omitted)

  • PDF

A Comparative Performance Study for Compute Node Sharing

  • Park, Jeho;Lam, Shui F.
    • Journal of Computing Science and Engineering
    • /
    • v.6 no.4
    • /
    • pp.287-293
    • /
    • 2012
  • We introduce a methodology for the study of the application-level performance of time-sharing parallel jobs on a set of compute nodes in high performance clusters and report our findings. We assume that parallel jobs arriving at a cluster need to share a set of nodes with the jobs of other users, in that they must compete for processor time in a time-sharing manner and other limited resources such as memory and I/O in a space-sharing manner. Under the assumption, we developed a methodology to simulate job arrivals to a set of compute nodes, and gather and process performance data to calculate the percentage slowdown of parallel jobs. Our goal through this study is to identify a better combination of jobs that minimize performance degradations due to resource sharing and contention. Through our experiments, we found a couple of interesting behaviors for overlapped parallel jobs, which may be used to suggest alternative job allocation schemes aiming to reduce slowdowns that will inevitably result due to resource sharing on a high performance computing cluster. We suggest three job allocation strategies based on our empirical results and propose further studies of the results using a supercomputing facility at the San Diego Supercomputing Center.

Research on Efficient Applicability Through Review on Standard for Selection of Construction Method for Railway Underground Crossing Transit (철도지하횡단 통과 공법 선정기준에 관한 검토를 통해 효율적인 적용성에 대한 연구)

  • Hwang, Young-Ho;Shon, Jung-Chul;Baek, Jong-Myeong
    • Proceedings of the KSR Conference
    • /
    • 2007.11a
    • /
    • pp.595-600
    • /
    • 2007
  • Greater expansion and more frequent operation of the railroad transportation system anticipated due to its characteristics including low cost, safety and mass transportation. Recently, effects on the railway structures due to expansion of newly constructed road, construction of subway, city gas pipeline, communication network, electric power network and construction of other railway underground crossing in accordance with urban planning and organization has influenced safe operation of trains. Accordingly, standard for selection of construction method that will enable construction of more economical and rational subway underground crossing structures by preventing problems occurring at the time of above construction works and accidents in safe operation of trains due to construction in advance is definitively necessary. Although there are numerous construction methods that can be applied at the time of construction of railway underground crossing, there are much difficulties in selection of appropriate construction method that considers characteristics of each construction method on non-excavation type construction method, train operation plan of number of operational routes and on-site circumstances. Therefore, this research aims to present rational standard for selection of construction method for such, and standard for slowdown speed and interception of train when passing the areas of slowdown in sectors under construction.

  • PDF

Processing Scrambled Wh-Constructions in Head-Final Languages: Dependency Resolution and Feature Checking

  • Hahn, Hye-ryeong;Hong, Seungjin
    • Language and Information
    • /
    • v.18 no.2
    • /
    • pp.59-79
    • /
    • 2014
  • This paper aims at exploring the processing mechanism of filler-gap dependency resolution and feature checking in Korean wh-constructions. Based on their findings on Japanese sentence processing, Aoshima et al. (2004) have argued that the parser posits a gap in the embedded clause in head-final languages, unlike in head-initial languages, where the parser posits a gap in the matrix clause. In order to verify their findings in the Korean context, and to further explore the mechanisms involved in processing Korean wh-constructions, the present study replicated the study done by Aoshima et al., with some modifications of problematic areas in their original design. Sixty-four Korean native speakers were presented Korean sentences containing a wh-phrase in four conditions, with word order and complementizer type as the two main factors. The participants read sentences segment-by-segment, and the reading times at each segment were measured. The reading time analysis showed that there was no such slowdown at the embedded verb in the scrambled conditions as observed in Aoshima et al. Instead, there was a clear indication of the wh-feature checking process in terms of a major slowdown at the relevant region.

  • PDF

A study on improvement of elderly welfare service focusing on the user of AI and the IoT

  • QUAN, Zhixuan;KANG, Minsoo
    • The Korean Journal of Food & Health Convergence
    • /
    • v.7 no.5
    • /
    • pp.1-7
    • /
    • 2021
  • The aging of the population has a fundamental impact on the national economy, including decline in productive population, atrophy of available funds, slowdown of technological innovation, slowdown of economic growth, and decrease in vitality of society as a whole. Increase of elderly population would lead to increase in elderly welfare consumers, which would also lead to increase the demand for elderly welfare services. However, due to the continuation of the low birth rate, there is a great shortage of human resources who can handle this. In such a situation, the main goal of the elderly welfare system in the future should aim to actively try to design effective policies, prepare systems, and implement services for the problems of the aged society, and to find ways to expand the finances, manpower, methods, and facilities necessary for the welfare of the elderly. Elderly welfare services in Korea have been changed and developed in accordance with socioeconomic changes such as industrialization and urbanization. This study examines the changes in elderly welfare services in Korea by the flow of times and presents a method which utilizes artificial intelligence and Internet of Things in services for the elderly welfare consumers to improve both quality and efficiency.

The Effect of the COVID-19 Pandemic on Stock Market Returns in Emerging Economies: Empirical Evidence from Panel Data

  • GNAHE, Franck Edouard;ASHRAF, Junaid;HUANG, Fei-Ming
    • The Journal of Asian Finance, Economics and Business
    • /
    • v.9 no.4
    • /
    • pp.191-196
    • /
    • 2022
  • From several socioeconomic perspectives, the present health crisis can be connected to the 2008 financial and economic catastrophe. Governments worldwide are working hard to keep the markets in check, as evidence suggests that the health crisis may soon become an economic crisis. This paper aims to analyze the effect of COVID-19 on the selected stock market. Using a panel of daily COVID-19 confirmed cases and deaths and the stock market from 22 developing countries, we exploit an oil price as a shock to the stock market and examine the effect of COVID-19 on the slowdown of the stock market. We find a negative and significant impact of COVID-19 on the stock market in the first stage till April. However, there is no net influence on the stock market downturn when we extend the period. However, further study suggests that the outbreak's negative influence on the selected stock market has diminished and has begun to decline as of mid-April. As a result of the COVID-19 effect on the chosen stock, our findings imply that the government in the chosen market should consider a regulatory mechanism to reduce the stock market slowdown induced by the pandemic COVID-19.