• The Transactions of the Korea Information Processing Society
• /
• v.7 no.8S
• /
• pp.2608-2619
• /
• 2000

This paper proposes the Handover Scheme for the mobile and describes the result of the performance analysis. In the conventional scheme of handover request, the withdrawal of terminal may occur because handover request is performed based on fixed signal level without considering network load and terminal mobility. The proposed scheme offers the minimization of withdrawal and handover blocking probability by means of the handover request of terminal based on the network load and terminal mobility. Conventional handover scheme has the sequential procedure that network performs resource check and path rerouting on the handover by MT(Mobile Terminal). Proposed handover scheme pre-processes the resource check before the handover request by predicting the handover request timo so that handover latency can be reduced. Moreover, path optimization is executed after the completion of handover in order to reduce handover latency. The rdduction of handover latency prevents the dropping of service by minimizing backward handover blocking. In summary, we propose the prediction of handover request time and decision method based on terminal, validating the performance of proposed scheme considering various cases of simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.3
• /
• pp.103-110
• /
• 2010

This paper addressed the implementation of the systematic performance analysis of Quality of Service (QoS) by using OPNET simulator in the interworking architecture of IEEE 802.16e (mobile WiMAX) and IEEE 802.11e (WLAN) wireless network. Four simulation cases were provided in OPNET simulator and a voice traffic was simulated with various performance metrics, such as Mean Opinion Score (MOS), end-to-end delay and packet transmission ratio. Based on the simulation results, the MOS value presented better in WiMAX to WiMAX case compared to others in both static and mobility case. Meanwhile, end-to-end delay was not greatly affected by mobility in four cases. However, mobility was affected much in MOS value and packet transmission ratio in WLAN to WLAN case than in others.

• 한국사회복지학회:학술대회논문집
• /
• 2004.06a
• /
• pp.3-50
• /
• 2004

${\cdot}$ Recent social policy and labour markets debates in Europe, responding to the difficulties faced by the traditional neo-Keynesian welfare state settlement, stress the value of positive investment alongside de-regulation and greater flexibility as a way of achieving both economic and social goals. ${\cdot}$ Patterns of policy reform are complex and reflect differing national circumstances. A general move towards deregulation, constraints on entitlement to passive benefits, programmes to enhance employment, particularly among high-risk groups such as single parents and young people, targeted subsidies for low earners and casemanagement may be identified. ${\cdot}$ In relation to investment in education, research and development and combined training and benefit programmes to enhance mobility between jobs the picture is less clear. Education standards continue to rise, but research and development spending stagnates and few countries have developed substantial ‘flexi-curity’ programmes to support job mobility. ${\cdot}$ The labour market tradition in much of Europe has been one of conflict between labour and employers. As labour grows weaker, new approaches develop. These tend to stress productivity agreements and greater flexibility in work practices within firms and reforms to passive social security systems more broadly, but movement to support the more challenging investment and flexi-curity policies is slow. ${\cdot}$ In general, social and labour market policies in Europe stress deregulation and negative activation more strongly than social investment and ‘flexi-curity’. The countries with high growth and employment achieve that goal by different routes: Sweden has a closely integrated social democratic corporatism with high spending on benefits and training programmes and the UK a more liberal market-oriented system, with lower spending, highly targeted benefits and less mobility support. ${\cdot}$ Europe has something to learn from Korea in achieving high investment in human capital and R and D, while Korea may have something to learn from Europe in social investment, particularly flexi-curity and equal opportunity policies.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.2
• /
• pp.1-7
• /
• 2019

Recently, multimedia streaming service has been activated, and the demand for high-quality multimedia convergence contents services is predicted to increase significantly in the future. The issues of the increasing network load due to the rise of multimedia streaming traffic must be addressed in order to provide QoS guaranteed services. To do this, an efficient network resource management and mobility support technologies are needed through seamless mobility support for heterogeneous networks. Therefore, in this paper, an MIH technology was used to recognize the network situation information in advance and reduce packet loss due to handover delays, and an ACLMIH-FHPMIPv6 is designed that can provide an intelligent interface through introducing a hierarchical mobility management technique in FPMIPv6 integrated network.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.47 no.2
• /
• pp.155-167
• /
• 2024

Distribution and logistics industries contribute some of the biggest GDP(gross domestic product) in South Korea and the number of related companies are quarter of the total number of industries in the country. The number of retail tech companies are quickly increased due to the acceleration of the online and untact shopping trend. Furthermore, major distribution and logistics companies try to achieve integrated data management with the fulfillment process. In contrast, small and medium distribution companies still lack of the capacity and ability to develop digital innovation and smartization. Therefore, in this paper, a deep learning-based demand forecasting & recommendation model is proposed to improve business competitiveness. The proposed model is developed based on real sales transaction data to predict future demand for each product. The proposed model consists of six deep learning models, which are MLP(multi-layers perception), CNN(convolution neural network), RNN(recurrent neural network), LSTM(long short term memory), Conv1D-BiLSTM(convolution-long short term memory) for demand forecasting and collaborative filtering for the recommendation. Each model provides the best prediction result for each product and recommendation model can recommend best sales product among companies own sales list as well as competitor's item list. The proposed demand forecasting model is expected to improve the competitiveness of the small and medium-sized distribution and logistics industry.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.5
• /
• pp.62-70
• /
• 2016

Ensuring walkability in a city where pedestrians and vehicles coexist is an issue of critical importance. The relative relationship between vehicle transit and walkability improvements complicates the evaluation of walkability, which thus necessitates the formation of a quantitative standard by which a methodological measurement of walkability can be achieved inside the pedestrian network. Therefore, a model is determined whereby quantitative indices such as, but not limited to, experiences of accessibility, mobility, and convenience within the network are estimated. This research proposes the integration of space syntax theory and the logit path choice model in the evaluation of walkability. Space syntax theory assesses adequacy of the constructed pedestrian network through calculation of the link integration value, while the logit model estimates its safety, mobility, and accessibility using probability. The advantage of the integrated model hence lies in its ability to sufficiently reflect such evaluation measures as the integration value, mobility convenience, accessibility potential, and safety experienced by the demand in a quantitative manner through probability computation. In this research, the Dial Algorithm is used to arrive at a solution to the logit model. This process requires that the physical distance of the pedestrian network and the perceptive distance of space syntax theory be made equivalent. In this, the research makes use of network expansion to reflect wait times. The evaluation index calculated through the integrated model is reviewed and using the results of this sample network, the applicability of the model is assessed.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.6
• /
• pp.284-298
• /
• 2022

It is necessary to acquire information on traffic safety facilities installed on the roadways specifically for the operation of autonomous vehicles. The purpose of this study is to prepare a Korean version of an integrated message-set design as a way to provide to autonomous vehicles standardized information on traffic safety facilities. In this study, necessary facilities are classified according to four criteria (no legal basis; not providing information to autonomous vehicles; providing duplicate information; not standardized, and too difficult to generalize) based on information that must be provided to operate autonomous vehicles. The priority of information delivery (gross negligence followed by behavior change) was classified according to the importance of the information to be provided during autonomous driving, and the form was defined for the classification code in the information delivered. Finally, the information location and delivery method of traffic facilities for compliance with SAE J2735 were identified. This study is meaningful in that it provides a plan for roadway operations by suggesting a method for providing information to autonomously driven vehicles.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.57-61
• /
• 2011

Large scale natural disasters such as floods and typhoons due to climate change have recently occurred with severe damage in all over the world. Especially, current disaster investigation in affected area takes too much time because it can be done by handcrafted. Also, it is lack of somewhat accuracy and objectiveness because it is influenced by investigator's judgment. Further, the current disaster investigation is difficult when damage area is very wide or investigator can't reach the affected area. Hence, we developed the integrated damage investigation system using stereo images and information technology for quick, accurate and objective investigation. Also, we applied the system to Bonghwa-gun in Gyeongsangbuk-do in 2008, Jecheon-si in Chungcheongbuk-do in 2009, and Namwon-si in Jeollabuk-do and Hapcheon-gun in Gyeongsangnam-do in 2010. This paper presents advancement and application of integrated damage investigation system using stereo images and information technology considering mobility, stability and user convenience in field.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.221.2-221.2
• /
• 2015

Graphene is very interesting 2 dimensional material providing unique properties. Especially, graphene has been investigated as a stretchable and transparent conductor due to its high mobility, high optical transmittance, and outstanding mechanical properties. On the contrary, high sheet resistance of extremely thin monolayer graphene limits its application. Artificially stacked multilayer graphene is used to decrease its sheet resistance and has shown improved results. However, stacked multilayer graphene requires repetitive and unnecessary transfer processes. Recently, growth of multilayer graphene has been investigated using a chemical vapor deposition (CVD) method but the layer controlled synthesis of multilayer graphene has shown challenges. In this paper, we demonstrate controlled growth of multilayer graphene using a two-step process with multi heating zone low pressure CVD. The produced graphene samples are characterized by optical microscope (OM) and scanning electron microscopy (SEM). Raman spectroscopy is used to distinguish a number of layers in the multilayer graphene. Its optical and electrical properties are also analyzed by UV-Vis spectrophotometer and probe station, respectively. Atomic resolution images of graphene layers are observed by high resolution transmission electron microscopy (HRTEM).

• Architectural research
• /
• v.2 no.1
• /
• pp.35-40
• /
• 2000

Housing Adjustment is a set of creative human activities that take place to meet various housing needs. Thus far, numerous studies have given attention to speculate a typology of those activities on an empirical base. Overall, though, little is known about its theoretical underpinning, due to the independent nature of each individual study in interpreting differences in conclusions. This study examines and compares results from two previous studies on housing adjustment. Previous research on housing adjustment suggests that, other than household and housing characteristics, housing satisfaction as an intervening variable is deeply associated with the choice of housing adjustment involved in mobility, home improvement, or cognitive adaptation. The two studies used similar theoretical schemes, asked similar questions, yet one sample consisted of Korean American residents and the other sample was poor housing residents in Korea. This study shows that differences in sample characteristics lead to a strong discrepancy in interpreting Speare's (1974) satisfaction theory of housing adjustment. For Korean Americans, housing satisfaction turned out to be a good predictor of housing adjustment preference, while it is not the case for poor housing residents in Korea. This implies that findings of any Single study can not be generalized directly to the population as a whole. Thus, continued effort should be made to compare specific findings from various research studies, seeking explanations for differences in conclusions. Theory can be legitimately built and strengthened in this integrated manner.