• 제목/요약/키워드: Measurement of Service Quality

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A Multibit Tree Bitmap based Packet Classification (멀티 비트 트리 비트맵 기반 패킷 분류)

  • 최병철;이정태
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.3B
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    • pp.339-348
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    • 2004
  • Packet classification is an important factor to support various services such as QoS guarantee and VPN for users in Internet. Packet classification is a searching process for best matching rule on rule tables by employing multi-field such as source address, protocol, and port number as well as destination address in If header. In this paper, we propose hardware based packet classification algorithm by employing tree bitmap of multi-bit trio. We divided prefixes of searching fields and rule into multi-bit stride, and perform a rule searching with multi-bit of fixed size. The proposed scheme can reduce the access times taking for rule search by employing indexing key in a fixed size of upper bits of rule prefixes. We also employ a marker prefixes in order to remove backtracking during searching a rule. In this paper, we generate two dimensional random rule set of source address and destination address using routing tables provided by IPMA Project, and compare its memory usages and performance.

Hybrid Monitoring Scheme for End-to-End Performance Enhancement of Real-time Media Transport (실시간 미디어 전송의 종단간 성능 향상을 위한 혼성 모니터링 기법)

  • Park Ju-Won;Kim JongWon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.10B
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    • pp.630-638
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    • 2005
  • As real-time media applications based on IP multicast networks spread widely, the end-to-end QoS (quality of service) provisioning for these applications have become very important. To guarantee the end-to-end QoS of multi-party media applications, it is essential to monitor the time-varying status of both network metrics (i.e., delay, jitter and loss) and system metrics (i.e., CPU and memory utilization). In this paper, targeting the multicast-enabled AG (Access Grid) group collaboration tool based on multi-Party real-time media services, a hybrid monitoring scheme that can monitor the status of both multicast network and node system is investigated. It combines active monitoring and passive monitoring approaches to measure multicast network. The active monitoring measures network-layer metrics (i.e., network condition) with probe packets while the passive monitoring checks application-layer metrics (i.e., user traffic condition by analyzing RTCP packets). In addition, it measures node system metrics from system API. By comparing these hybrid results, we attempt to pinpoint the causes of performance degradation and explore corresponding reactions to improve the end-to-end performance. The experimental results show that the proposed hybrid monitoring can provide useful information to coordinate the performance improvement of multi-party real-time media applications.

A Study on Performance Measurement of Generational Diversity Company using Balanced Scorecard (BSC): The case of Japanese Companies (균형성과평가(BSC)모델을 활용한 청년·고령자 고용상생기업의 경영성과측정 -일본의 사례분석을 중심으로-)

  • Kim, Moon-Jung;Chung, Soon-Dool;Kim, Ju-Hyun
    • Korean Journal of Labor Studies
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    • v.23 no.1
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    • pp.221-253
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    • 2017
  • This study aims at analyzing the management strategy and performance of companies that have been pursuing Generational Diversity. The management strategies were examined in terms of production, organizational structure and skill development. Performance was then evaluated using Balanced Scorecard (BSC). We selected four Japanese companies that practice Generational Diversity between the younger(age less then 34) and older generation(age older then 65). Our findings suggest the following. The common management strategies of the four companies include 1) creating generation-diverse teams 2) ensuring flexible work arrangements and 3) providing skill training programs. These strategies have yield positive outcomes such as sales increase, cost reduction (financial perspective) and expansion of the market share (customer perspective). Non-financial performance includes improvement of product and service quality (internal business perspective) and skill improvement of both the young and the old workers (learning and growth perspective). This study provides practical implications to domestic companies for their successful management of generational diversity in workplace.

QoS-Aware Power Management of Mobile Games with High-Load Threads (CPU 부하가 큰 쓰레드를 가진 모바일 게임에서 QoS를 고려한 전력관리 기법)

  • Kim, Minsung;Kim, Jihong
    • KIISE Transactions on Computing Practices
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    • v.23 no.5
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    • pp.328-333
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    • 2017
  • Mobile game apps, which are popular in various mobile devices, tend to be power-hungry and rapidly drain the device's battery. Since a long battery lifetime is a key design requirement of mobile devices, reducing the power consumption of mobile game apps has become an important research topic. In this paper, we investigate the power consumption characteristics of popular mobile games with multiple threads, focusing on the inter-thread. From our power measurement study of popular mobile game apps, we observed that some of these apps have abnormally high-load threads that barely affect the user's gaming experience, despite the high energy consumption. In order to reduce the wasted power from these abnormal threads, we propose a novel technique that detects such abnormal threads during run time and reduces their power consumption without degrading user experience. Our experimental results on an Android smartphone show that the proposed technique can reduce the energy consumption of mobile game apps by up to 58% without any negative impact on the user's gaming experience.

Received Signal Performance Measurement in the Urban Area for the Variable DVB-H Parameters (DVB-H 파라미터 변화에 따른 도심 지역에서의 수신 신호 성능 측정)

  • Song, Ki-Hong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.10
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    • pp.1181-1188
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    • 2007
  • This paper presents the measured signal performances in the urban environment for the DVB-H parameters such as code rate, burst size, FFT mode and modulation technique to analyze the DVB-H signal performance avaible for the embodiment of single frequency network to improve the frequency efficiency. Measurements were performed for the case for applying and non-applying MPE-FEC technique simultaneously. Results show that the most outstanding performance are found in the case of QPSK modulation, 1/2 code rate, 2 k FFT mode and 512 burst size. In addition, the signal performance by the SFN with 1/8 guard interval becomes superiour in comparision with the measured data from each site and the data from SFN with 1/32 guard interval. The analysis of the results can be instructive for the improvement of the signal performance and broadcasting quality for the terrestrial digital mobile broadcasting service.

The Study on Empirical Propagation Path Loss in the Airport Cargo Terminal Environment (공항 화물터미널 환경에서 실험적인 패스 로스에 관한 연구)

  • Kim, Kyung-Tae;Park, Hyo-Dal
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.12
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    • pp.1140-1147
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    • 2013
  • In this paper, The path loss model of Air Traffic Control(ATC) telecommunication radio channel has been studied at the Incheon International Airport(IIA) Cargo Terminal. We measured one frequency among VHF channel bands. The transmitting site was located at different locations with different heights. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponent at IIA Cargo terminal area were 3.67 and 3.39 respectively in first and second transmitting sites. The deviation of prediction error is 14.42 and 10.38. The new path loss equation at the IIA Cargo terminal area was also developed using the derived path loss parameters. The new path loss was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

Evaluation Criteria for Garment of Korean-Chinese College Students in Yanbian, China (중국 연변 지역 조선족 대학생의 의류 제품 평가 기준)

  • 김순심
    • Journal of the Korea Fashion and Costume Design Association
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    • v.5 no.3
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    • pp.111-123
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    • 2003
  • This study is designed to understand evaluation criteria for garment depending on demographic factors among college students in Yanbian, China. Questionnaire was used for measurement tools to study the subject of the thesis. The main study was conducted against 450 college students from May 17 to June 5, 2001. The data for the study were analyzed using SAS PC program for frequency distribution, percentage, t-test, and one way ANOVA. The evaluation criteria for garment are affected by demographic factors such as gender, average monthly household income, monthly expense for clothing. The result was showed as follows: The evaluation criteria for garment based on gender showed almost no meaningful different between male and female college students. Means on factors considered highly in selecting clothes was studied. The result shows that 'fit to the body, 'quality', 'color' and 'pattern' are considered most highly and 'harmony with other clothes', 'after service', design' 'easy to manage' and 'price' are considered relatively highly, but 'brand' and 'trendy fashion' were not considered highly. A meaningful difference was showed only in one area-trendy fashion-among three different income level groups. Those with an average monthly household income between 500 and 2,000yuan showed a highest tendency compared to those with above 2,000yuan and those with 500yuan. In terms of evaluation criteria for garment based on monthly expense for clothing, 'brand' is the only area which showed a meaningful difference. Respondents with monthly clothing expense of above 100yuan showed a higher means than those with below 100yuan.

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Empirical Propagation Path Loss Model for ATC Telecommunication in the Concourse Environment (콘코스 환경에서 항공 정보통신의 실험적인 전파 경로 모델에 관한 연구)

  • Kim, Kyung-Tae;Park, Hyo-Dal
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.9
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    • pp.765-772
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    • 2013
  • In this paper, we studied the path loss model of Air Traffic Control(ATC) telecommunication radio channel at the Incheon International Airport(IIA) concourse area. We measured wave propagation characteristics on the two frequencies among VHF/UHF channel bands. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency, and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponents at Concourse area were 3.1/3.13 and 3.01/3.38 respectively in 128.2MHz and 269.1MHz. The deviation of prediction error is 2.77/3.17 and 4.01/3.66. The new path loss equation at the Concourse area was also developed using the derived path loss parameters. The new path loss model was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

Study on the Effects of Shop Choice Properties on Brand Attitudes: Focus on Six Major Coffee Shop Brands (점포선택속성이 브랜드 태도에 미치는 영향에 관한 연구: 6개 메이저 브랜드 커피전문점을 중심으로)

  • Yi, Weon-Ho;Kim, Su-Ok;Lee, Sang-Youn;Youn, Myoung-Kil
    • Journal of Distribution Science
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    • v.10 no.3
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    • pp.51-61
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    • 2012
  • This study seeks to understand how the choice of a coffee shop is related to a customer's loyalty and which characteristics of a shop influence this choice. It considers large-sized coffee shops brands whose market scale has gradually grown. The users' choice of shop is determined by price, employee service, shop location, and shop atmosphere. The study investigated the effects of these four properties on the brand attitudes of coffee shops. The effects were found to vary depending on users' characteristics. The properties with the largest influence were shop atmosphere and shop location Therefore, the purpose of the study was to examine the properties that could help coffee shops get loyal customers, and the choice properties that could satisfy consumers' desires The study examined consumers' perceptions of shop properties at selection of coffee shop and the difference between perceptual difference and coffee brand in order to investigate customers' desires and needs and to suggest ways that could supply products and service. The research methodology consisted of two parts: normative and empirical research, which includes empirical analysis and statistical analysis. In this study, a statistical analysis of the empirical research was carried out. The study theoretically confirmed the shop choice properties by reviewing previous studies and performed an empirical analysis including cross tabulation based on secondary material. The findings were as follows: First, coffee shop choice properties varied by gender. Price advantage influenced the choice of both men and women; men preferred nearer coffee shops where they could buy coffee easily and more conveniently than women did. The atmosphere of the coffee shop had the greatest influence on both men and women, and shop atmosphere was thought to be the most important for age analysis. In the past, customers selected coffee shops solely to drink coffee. Now, they select the coffee shop according to its interior, menu variety, and atmosphere owing to improved quality and service of coffee shop brands. Second, the prices of the brands did not vary much because the coffee shops were similarly priced. The service was thought to be more important and to elevate service quality so that price and employee service and other properties did not have a great influence on shop choice. However, those working in the farming, forestry, fishery, and livestock industries were more concerned with the price than the shop atmosphere. College and graduate school students were also affected by inexpensive price. Third, shop choice properties varied depending on income. The shop location and shop atmosphere had a greater influence on shop choice. The customers in an income bracket of less than 2 million won selected low-price coffee shops more than those earning 6 million won or more. Therefore, price advantage had no relation with difference in income. The higher income group was not affected by employee service. Fourth, shop choice properties varied depending on place. For instance, customers at Ulsan were the most affected by the price, and the ones at Busan were the least affected. The shop location had the greatest influence among all of the properties. Among the places surveyed, Gwangju had the least influence. The alternate use of space in a coffee shop was thought to be important in all the cities under consideration. The customers at Ulsan were not affected by employee service, and they selected coffee shops according to quality and preference of shop atmosphere. Lastly, the price factor was found to be a little higher than other factors when customers frequently selected brands according to shop properties. Customers at Gwangju reacted to discounts more than those in other cities did, and the former gave less priority to the quality and taste of coffee. Brand preference varied depending on coffee shop location. Customers at Busan selected brands according to the coffee shop location, and those at Ulsan were not influenced by employee kindness and specialty. The implications of this study are that franchise coffee shop businesses should focus on customers rather than aggressive marketing strategies that increase the number of coffee shops. Thus, they should create an environment with a good atmosphere and set up coffee shops in places that customers have good access to. This study has some limitations. First, the respondents were concentrated in metropolitan areas. Secondary data showed that the number of respondents at Seoul was much more than that at Gyeonggi-do. Furthermore, the number of respondents at Gyeonggi-do was much more than those at the six major cities in the nation. Thus, the regional sample was not representative enough of the population. Second, respondents' ratio was used as a measurement scale to test the perception of shop choice properties and brand preference. The difficulties arose when examining the relation between these properties and brand preference, as well as when understanding the difference between groups. Therefore, future research should seek to address some of the shortcomings of this study: If the coffee shops are being expanded to local areas, then a questionnaire survey of consumers at small cities in local areas shall be conducted to collect primary material. In particular, variables of the questionnaire survey shall be measured using Likert scales in order to include perception on shop choice properties, brand preference, and repurchase. Therefore, correlation analysis, multi-regression, and ANOVA shall be used for empirical analysis and to investigate consumers' attitudes and behavior in detail.

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Characteristics and Risk Assessment of Heavy Metals in the Stormwater Runoffs from Industrial Region Discharged into Shihwa Lake (시화호 산업지역 강우유출수 내 중금속 유출특성 및 위해성 평가)

  • Ra, Kongtae;Kim, Joung-Keun;Lee, Jung-Moo;Lee, Seung-Yong;Kim, Eun-Soo;Kim, Kyung-Tae
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.4
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    • pp.283-296
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    • 2014
  • The distribution of heavy metals in the stormwater runoffs from industrial sites around Shihwa Lake that implements the total pollutant load management system (TPLMS) was studied to characterize the temporal changes of metal concentrations and to assess the ecological risk in dissolved and particulate phases of the selected metals. The dissolved Co and Ni concentration demonstrated first flush and tended to decrease with increasing of the duration of rainfall. The intensity of precipitation was found to be the main controlling factor of particulate metals in the stromwater runoffs. The particulate concentration of Pb accounted for 97.2% so the particulate phase was its main form. Other metals followed the sequence: Pb>Cu>Cd>Co>Zn>Ni. The particulate-dissolved partitioning coefficient ($K_d$) indicated that the $K_d$ of Pb were bigger than that of other metals because the metal Pb in the stormwater runoffs is quickly removed into the particulate phase. In a single day rainfall event, total runoff fluxes for total metals as the sum of dissolved and particulate forms through only two sewer outlets were 2.21 kg for Co, 30.5 kg for Ni, 278.3 kg for Cu, 398.3 kg for Zn, 0.39 kg for Cd and 40.0 kg for Pb, respectively. Given the annual rainfall, the number of rain days and the basin area for total pollutant load management system (TPLMS) of Shihwa area, enormous amount of non-point metal pollutants were entered into Lake with any treatment. The dissolved metals (e.g., Ni, Cu and Zn) in the stormwater runoffs exceeded the acute water quality criteria. Additionally, all metals were significantly enriched in the particulate phase and exceeded the PEL criteria of sediment quality guidelines (SQGs). These results indicated that the heavy metals in the stormwater runoffs may pose a very high ecological risk to the coastal environments and ecosystem.