• Industrial Engineering and Management Systems
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• 제8권3호
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• pp.181-193
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• 2009

This paper presents a framework for controlling mobile multiple robots connected by communication networks. This framework provides novel methods to control coordinated systems using mobile agents. The combination of the mobile agent and mobile multiple robots opens a new horizon of efficient use of mobile robot resources. Instead of physical movement of multiple robots, mobile software agents can migrate from one robot to another so that they can minimize energy consumption in aggregation. The imaginary application is making "carts," such as found in large airports, intelligent. Travelers pick up carts at designated points but leave them arbitrary places. It is a considerable task to re-collect them. It is, therefore, desirable that intelligent carts (intelligent robots) draw themselves together automatically. Simple implementation may be making each cart has a designated assembly point, and when they are free, automatically return to those points. It is easy to implement, but some carts have to travel very long way back to their own assembly point, even though it is located close to some other assembly points. It consumes too much unnecessary energy so that the carts have to have expensive batteries. In order to ameliorate the situation, we employ mobile software agents to locate robots scattered in a field, e.g. an airport, and make them autonomously determine their moving behaviors by using a clustering algorithm based on the Ant Colony Optimization (ACO). ACO is the swarm intelligence-based methods, and a multi-agent system that exploit artificial stigmergy for the solution of combinatorial optimization problems. Preliminary experiments have provided a favorable result. In this paper, we focus on the implementation of the controlling mechanism of the multi-robots using the mobile agents.

• ETRI Journal
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• 제44권6호
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• pp.966-976
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• 2022

Optical wireless communication, or free space optics, is a promising solution for backhauls in sixth-generation mobile systems. However, the susceptibility of optical links to weather conditions has led to FSO links being furnished with radio frequency (RF) backups. These Hybrid FSO/RF systems provide enhanced link availability but lead to RF resource wastage. Cognitive radio technology, in contrast, is well known for its optimal use of RF resources and may be combined with an FSO link to create a Cognitive Hybrid FSO/RF system. This work uses such a system to analyze a configuration for a mobile backhaul in sixth-generation mobile systems. This configuration can seamlessly coexist with established large scale RF cellular networks. The performance of this configuration is analyzed with respect to outage probability and average bit error by considering the impact of optical channel turbulence, misalignment loss, RF interference, and noise. Mathematical closed-form expressions are verified by simulations.

• 대한환경공학회지
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• 제36권8호
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• pp.570-578
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• 2014

수심이 낮은 하구에서 바람이 국부적인 해수면 상승/하강에 미치는 영향을 연구하기 위해 Mobile Bay에 3차원 해수 순환모델을 적용하였다. Mobile Bay의 남단 경계면, 즉 northern Gulf of Mexico에서 시작된 조위는 Mobile River system 북부까지 직접적인 영향을 준다. 그러나 Mobile Bay 남단에서 발생한 조위변화는 Mobile Bay 북부로 이동하면서 Mobile River system으로부터 들어오는 담수와 국부적 바람의 영향으로 왜곡된다. Mobile Bay 남단에 위치한 기상관측소에서의 바람정보를 Mobile Bay 전체에 적용하였을 경우 Mobile Bay 북부에서 실제보다 강한 바람의 영향으로 과대한 수위 상승과 하강 현상이 발생하였다. 그러나 Mobile Bay 남단과 중단에 위치한 두 개의 관측소에서 측정된 바람 정보를 활용하였을 경우 Mobile Bay 북부에서의 조위 변화를 보다 정확하게 재현하는 것으로 나타났다. 특히 바람의 강도가 센 경우 Mobile Bay 남단과 북단의 풍속이 현저하게 차이나는 것으로 나타났으며(~ 88%), 이는 Mobile Bay 북단에서 나무와 건물 등의 영향으로 바람의 강도가 급격하게 줄어들었기 때문으로 판단된다. 따라서 Mobile Bay와 같이 수심이 낮고 국부적으로 풍속이 다른 하구 또는 만에서의 수위변화 재현 또는 예측을 위해서는 국부적인 바람 정보가 매우 중요한 것으로 연구되었다.

• 한국군사과학기술학회지
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• 제11권1호
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• pp.5-14
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• 2008

In this paper, we propose operational concepts and technology requirements for guard and surveillance robots in military field. After surveying on current trend of guard robots, we present an operational scenario and technology requirements. To begin with, we discriminate the use of fixed type guard robots(fixed robots) and mobile guard and surveillance robots(mobile robots). Fixed robots are used for substituting daily guard by human soldier. In contrast, mobile robots are used for compensating shadow area where not to be covered by fixed type robots. To be specific, mobile robots adopt communication relays to extend operational range and sensor networks to collecting information. In addition, we present technology requirements composed of wireless communication system, platform, sensor nodes, unmanned driving technology, power supply system and IFF etc. In conclusion, in order to maximize co-operational functionality, fixed robots and mobile robots should be tightly related.

• ETRI Journal
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• 제33권1호
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• pp.110-120
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• 2011

As information technology rapidly develops and the period required to enter new technology shortens, there emerges a wide variety of alternatives for consumers. When there are many alternatives in the market, users choose after making comparisons. This process of making comparisons is our research key. We established a research model to find a mixed effect that comes from new attitudes to technology adoption and alternative's continuous usage intention. The effect is revealed through a relative attractiveness (RA) factor to explain a user's process of comparison. We empirically test our research model in the new media services, such as mobile TV, web TV, and mobile IPTV. According to our research results, a continuous usage intention of an existing technology is an important factor to explain the adoption of a new technology. So, the contribution of our research is in finding a role for the RA factor in research in new technology adoption.

• 한국IT서비스학회지
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• 제16권4호
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• pp.33-46
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• 2017

Increasing popularity of smartphone is creating many changes in payment market sector also. The new fin-tech and simple mobile payment service have provided convenience as well as various benefits and value-added services to create new payment culture. However, the infrastructure of offline shops is too poor for users to use the simple mobile payment services in Korea. There are several reasons why the support of simple mobile payment services by offline shops has reached the limit in Korea. They include the reluctance of shop owners due to highly priced devices, the failure of NFC of the leading offline payment infrastructure to support iOS, the services that are biased to the specific manufacturers and smartphones (Samsung Pay and LG Pay), prefer large shops (SSG Pay and L PAY), and focus on online transactions. This study used the Bluetooth technology that is the standard feature built in all smartphone to expand the offline shops that accept the simple mobile payment services ensuring universality and scalability from the convenience of customer's and service provider's aspects. Applying the same payment scene as the existing NFC payment method from the user's aspect and the Bluetooth technology from the service provider's aspect enables support of all smartphones and offering value-added services such as electronic receipt and promotions through the large-capacity bidirectional data transfer. This study is intended to review the simple mobile payment services in Korea and other countries, propose the simple mobile payment service model for Korea by analyzing the Bluetooth technology and preceding studies of payment services using BLE technology, and develop the pilot system using the BLE technology to verify the proposed system with actual shops.

• Journal of Information Technology Applications and Management
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• 제21권2호
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• pp.49-79
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• 2014

The adoption of technology has always been of interest to academicians and practitioners of the field of Management Information System. This is so because without proper and adequate adoption, technology-no matter how beneficial or advanced it may be-will be of little value to users. Numerous researches, such as the researches of the Technology Acceptance Model (TAM) or the Unified Theory of Acceptance and Use of Technology (UTAUT), had been conducted to understand the human nature in association with the adoption or rejection of technologies that have bombarded the users. The coming of smart technologies (i.e., smart phones and devices), however, seems to have fundamentally changed the environment for adoption. The ubiquity combined with mobility of technology, especially when it comes to mobile apps, seem to make the old PC era of two-stage-pre and post-adoption models obsolete. A new model of adoption that identifies the determinants of technology acceptance and continuance is needed for the smart age. To this end, this paper undertakes an empirical study, by analyzing 229 users of Social Networking Service (SNS) mobile apps, to identify the role of user experience on the multi-stage adoption of technology, and provides results that User Experience (UX) plays the crucial role of bridging the separate stages of pre and post adoption of technologies. The paper concludes by providing practical implications of the new model as it relates to mobile apps and technologies, and recommendations for further studies to get a better understanding of technology adoption in the smart age.

• 정보학연구
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• 제8권1호
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• pp.11-25
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• 2005

The purposes of this study were to explain consumer attitude, expenses and satisfaction of mobile-phone Users. The data of this study used from Pollever.com. This study was satisfaction of mobile-phone users in Korea. The users were consumers of Samsung, LG, SK-Telecom and Pantack. The critical success factor was on the subside for mobile-phone in the growth of mobile service, which we can analyze in its positive effects. Fifty percent of consumers were unsatisfaction with local companies without Samsung. Now most of local mobile-companies will developed music-phone, high-tec camera-phone, hi-slim phone, and health-phone. But, the results of this study are as fallow: Most of consumer' main issues were design, weight, and brand power. It was in that it played the driving force to upgrade the local mobile-phone services into international level with the explosive growth in business by providing cheap phones.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.705-706
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• 2006

A novel plug and play system for a mobile device has been proposed and demonstrated to provide an easy inter-operation between the mobile device and external modules. It supports an automatic installation and execution of the device drivers stored in the external modules into the mobile devices when the external module is connected to the mobile device. It also enables an automatic removal of the derivers when the external module is disconnected from the mobile device, which makes the user use the resource of the mobile devices more efficiently.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.973-978
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• 2005

In this paper, we investigate an improved mobile robot localization method using Kalman filter. The highlight of the paper lies in the formulation of combined Kalman filter and its application to mobile robot experiment. The combined Kalman filter is a kind of extended Kalman filter which has an extra degree of freedom in Kalman filtering recursion. It consists of the standard Kalman filter, i.e., the predictor-corrector and the perturbation estimator which reconstructs unknown dynamics in the state transition equation of mobile robot. The combined Kalman filter (CKF) enables to achieve robust localization performance of mobile robot in spite of heavy perturbation such as wheel slip and doorsill crossover which results in large odometric errors. Intrinsically, it has the property of integrating the innovation in Kalman filtering, i.e., the difference between measurement and predicted measurement and thus it is so much advantageous in compensating uncertainties which has not been reflected in the state transition model of mobile robot. After formulation of the CKF recursion equation, we show how the design parameters can be determined and how much beneficial it is through simulation and experiment for a two-wheeled mobile robot under indoor GPS measurement system composed of four ultrasonic satellites. In addition, we discuss what should be considered and what prerequisites are needed to successfully apply the proposed CKF in mobile robot localization.