• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.4
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• pp.249-255
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• 2022

The COVID-19 virus appeared in 2019 and is extremely contagious. Because it is very infectious and has a huge impact on people's mobility. In this paper, multiple linear regression and random forest models are used to predict the number of COVID-19 cases using COVID-19 infection status data (open source data provided by the Ministry of health and welfare) and Google Mobility Data, which can check the liquidity of various categories. The data has been divided into two sets. The first dataset is COVID-19 infection status data and all six variables of Google Mobility Data. The second dataset is COVID-19 infection status data and only two variables of Google Mobility Data: (1) Retail stores and leisure facilities (2) Grocery stores and pharmacies. The models' performance has been compared using the mean absolute error indicator. We also a correlation analysis of the random forest model and the multiple linear regression model.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.255-257
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• 2004

The study for ubiquitous computing infra is proceeding actively, it make possible to use service and access network anywhere, anytime because of wire/wireless communication technology and progress of hardware. Domestically, study for the network mobility support technology which is the key technology for future ubiquitous computing realization have progressed, but that is insufficient. Especially, there is no study for independent mobility support study about railway wireless network. So, this study propose network mobility management technology for mobile network infra in railway and proper network model in train.

• Journal of Astronomy and Space Sciences
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• v.29 no.4
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• pp.413-422
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• 2012

In recent years, a number of missions have been planned and conducted worldwide on the planets such as Mars, which involves the unmanned robotic exploration with the use of rover. The rover is an important system for unmanned planetary exploration, performing the locomotion and sample collection and analysis at the exploration target of the planetary surface designated by the operator. This study investigates the development of mobility system for the rover ground model necessary to the planetary surface exploration for the benefit of future planetary exploration mission in Korea. First, the requirements for the rover mobility system are summarized and a new mechanism is proposed for a stable performance on rough terrain which consists of the passive suspension system with 8 wheeled double 4-bar linkage (DFBL), followed by the performance evaluation for the mechanism of the mobility system based on the shape design and simulation. The proposed mobility system DFBL was compared with the Rocker-Bogie suspension system of US space agency National Aeronautics and Space Administration and 8 wheeled mobility system CRAB8 developed in Switzerland, using the simulation to demonstrate the superiority with respect to the stability of locomotion. On the basis of the simulation results, a general system configuration was proposed and designed for the rover manufacture.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.3
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• pp.91-96
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• 2015

Recently, the 'mobility' is one of the essential item in the field of IT. This means that 'mobility' are good mediators to get collecting user's behavior and provide freedom of mobility service for user's. This paper is proposed a mobility process orchestration(MPO) model that provide multimedia to various devices. The orchestration model provides the structure and function that can be objectify a physical devices in a user's environment to provide orchestrated service of various devices to user using a concept of MSMP(Multi Source Multi Platform). Also, using the concept of Choreography can be extracted appropriate device of the various media formats for harmonious service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2230-2239
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• 1998

Recently, mobility support of connectionless mobile ATM data service has been mainly studied in wireless ATM communication network. this paper shows the network model for the mobility support of connectionless data service in ATM network, and proposes the methods to minimize COIP (care of IP address) acquisition processing time for MH(mobile host)migration. Th echaracteristics of proposed methods, COIP acquisition probability and IP data communication sequence of proposed model, are discussed in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.662-668
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• 2011

This paper analyzes the performance of the Ad hoc On-demand Distance Vector (AODV) routing protocol and Optimized Link State Routing (OLSR) for Mobile Ad hoc Networks (MANETs) using node mobility models. Mobility affects the performance of a routing protocol as it causes changes to network topology. Thus, evaluating the performance of a MANET routing protocol requires mobility models that can accurately represent the movements of mobile nodes. Therefore, this paper evaluates the performance of the AODV and OLSR routing protocols using the random way point model and the Levy walk model by the ns-2 simulations.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.93-101
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• 2020

Shipyards are potential environments for using IoT services, sensor networks, and delay tolerant networks. Simulations of those services and networks strongly rely on human mobility models. Results obtained with an unrealistic model may not reflect the true performance of applications, protocols, and algorithms in a shipyard. A lot of synthetic models for human movements have been studied but most of them are generic and focus on the daily movements of humans on city scales. Nevertheless, workers in shipyards have unique movement characteristics such as movement speed, pause time, and attractions places. For instance, workers usually move to some places, where they work, and rarely move to other places in the factory. Movement characteristics of workers not only depend on workers but also on tasks, which they do. For instance, workers, who paint ships, have similar movement speed and pause time. Hence, in this paper, human movements in shipyards are studied. We propose a new human mobility model called the human mobility mode in shipyards (MIS). In MIS, workers are classified into multiple types. Movement characteristics of a worker are similar to other workers in the same type. Based on the visiting probability, workers have some places, where they frequently visits, and some places, where they rarely visit. We analyze real mobility traces and studie to achieve human movement characteristics from real traces. The results show that MIS provides a well-match to the movement characteristic from real traces.

• Journal of the Korean Home Economics Association
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• v.36 no.1
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• pp.65-79
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• 1998

The purposes of this study were to establish a conceptual model on the woman's labor force participation and mobility in the labor market and to analyze the correlation between them. Included in those models were two independent variable sets. The one was related to household's financial conditions and the other was associated to the woman's role such as marital status, the number of children and the existence of young children. KHPS's national data was used and the Binomial Probit Model and Bivariate Probit Model were employed to analyse the effects of independent variables and the correlations between two dependent variables. The results of this study were as follows. The rate of women's labor force participation and the percentage of mobility willingness were 15.4% and 22.0%. Among the variables which have affected women's labor force participation were total wage income, non-wage income, expenditure on children's education and the subject judgement of their financial status. The existence of children under the age of 6 and marital status had significant influences on women's mobility willingness. The correlation between women's labor force participation and mobility willingness was very significant statistically. These findings clarified the status of woman as a secondary worker and pointed that a woman's economic activity would be subject to the woman's condition rather than her human capital.

• Journal of Information Processing Systems
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• v.3 no.1
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• pp.1-7
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• 2007

In mobile ad hoc networks, an application scenario requires mostly collaborative mobility behavior. The key problem of those applications is scalability with regard to the number of multicast members as well as the number of the multicast group. To enhance scalability with group mobility, we have proposed a multicast protocol based on a new framework for hierarchical multicasting that is suitable for the group mobility model in MANET. The key design goal of this protocol is to solve the problem of reflecting the node's mobility in the overlay multicast tree, the efficient data delivery within the sub-group with group mobility support, and the scalability problem for the large multicast group size. The results obtained through simulations show that our approach supports scalability and efficient data transmission utilizing the characteristic of group mobility.

• Journal of Service Research and Studies
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• v.9 no.4
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• pp.19-40
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• 2019

Mobility as a Service is a service conception to achieve the intelligent transportation system. Its aims to improve the travel experience. In one platform, it connects various transportation modes to offer service and users only need to pay in one time for the whole travel. But the single MaaS platform easily faces the problems such as low user traffic, low retention rate and the access to markets of the this service is still unfound. From the perspective of bicycle-sharing, this research makes the MaaS concept into bicycle-sharing to build a better service model. The bicycle-sharing combine with the MaaS concept is innovative in business model, travel model and service architecture. In addition, this research also tests users' expectations for service model. The research shows that MaaS-based bicycle-sharing could offer flexible and convenient travel experience in the aspects of combined transportation, travel, transfer and payment, and it also makes it possible to make travel services according to need, and sustainable transport.