• The Journal of Information Systems
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• 제14권3호
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• pp.48-52
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• 2005

The Mobile agent-based distributed systems become obtaining significant popularity as a potential vehicle to allow software components to be executed on heterogeneous environments despite mobility of users and computations. However, as these systems generally force mobile agents to use only common functionalities provided in every execution environment, the agents may not access environment-specific resources. In this paper, we propose a new framework using Aspect Oriented Programming technique to accommodate a variety of static resources as well as dynamic ones whose amount is continually changed at runtime even in the same execution environment. Unlike previous works, this framework divides roles of software developers into three groups to relieve application programmers from the complex and error prone parts of implementing dynamic adaptation and allowing each developer to only concentrate on his own part. Also, the framework enables policy decision makers to apply various adaptation policies to dynamically changing environments for adjusting mobile agents to the change of their resources.

• Journal of the Korean Institute of Intelligent Systems
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• 제23권4호
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• pp.332-340
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• 2013

This paper reports a programming toolkit for implementing localization and navigation of a mobile robot both in real world and simulation. Many of the previous function libraries are difficult to use because of their complexity or lack of usability. The proposed toolkit consist of functions for dead reckoning, motion model, measurement model, and operations on directions or heading angles. The dead reckoning and motion model deals with differential drive robot and bicycle type robot driven by front wheel or rear wheel. The functions can be used for navigation in both real environment and simulation. To prove the feasibility of the toolkit, simulation results are shown along with the results in real environment. It is expected the proposed toolkit is used for test of algorithms for mobile robot navigation such as localization, map building, and obstacle avoidance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.3134-3155
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• 2020

In this paper, we study the joint radio and computational resource allocation in the ultra-dense mobile-edge computing networks. In which, the scenario which including both computation offloading and communication service is discussed. That is, some mobile users ask for computation offloading, while the others ask for communication with the minimum communication rate requirements. We formulate the problem as a joint channel assignment, power control and computational resource allocation to minimize the offloading cost of computing offloading, with the precondition that the transmission rate of communication nodes are satisfied. Since the formulated problem is a mixed-integer nonlinear programming (MINLP), which is NP-hard. By leveraging the particular mathematical structure of the problem, i.e., the computational resource allocation variable is independent with other variables in the objective function and constraints, and then the original problem is decomposed into a computational resource allocation subproblem and a joint channel assignment and power allocation subproblem. Since the former is a convex programming, the KKT (Karush-Kuhn-Tucker) conditions can be used to find the closed optimal solution. For the latter, which is still NP-hard, is further decomposed into two subproblems, i.e., the power allocation and the channel assignment, to optimize alternatively. Finally, two heuristic algorithms are proposed, i.e., the Co-channel Equal Power allocation algorithm (CEP) and the Enhanced CEP (ECEP) algorithm to obtain the suboptimal solutions. Numerical results are presented at last to verify the performance of the proposed algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제22권1호
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• pp.9-16
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• 2018

Predictive control is a very practical method that obtain the current input that minimizes the future errors of the reference command and state by use of the predictive model of the controlled object, and can also consider the constraints of the state and input. Although there have been studies in which predictive control is applied to mobile robots, performance has not been optimized as various control parameters for determining control performance have been arbitrarily specified. In this paper, we apply the genetic algorithm to the trajectory tracking control of a mobile robot with input constraints in order to minimize the trajectory tracking errors through control parameter tuning, and apply the quadratic programming Hildreth method to reflect the input constraints. Through the computer simulation, the superiority of the proposed method is confirmed by comparing with the existing method.

• Journal of Communications and Networks
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• 제7권4호
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• pp.471-477
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• 2005

This paper proposes an efficient constraint-based optimization model for the design of 3G mobile networks, such as universal mobile telecommunications system (UMTS). The model concerns about finding a set of sites for locating radio network controllers (RNCs) from a set of pre-defined candidate sites, and at the same time optimally assigning node Bs to the selected RNCs. All these choices must satisfy a set of constraints and optimize an objective function. This problem is NP-hard and consequently cannot be practically solved by exact methods for real size networks. Thus, this paper proposes a hybrid search strategy for tackling this complex and combinatorial optimization problem. The proposed hybrid search strategy is composed of three phases: A constraint satisfaction method with an embedded problem-specific goal which guides the search for a good initial solution, an optimization phase using local search algorithms, such as tabu algorithm, and a post­optimization phase to improve solutions from the second phase by using a constraint optimization procedure. Computational results show that the proposed search strategy and the model are highly efficient. Optimal solutions are always obtained for small or medium sized problems. For large sized problems, the final results are on average within $5.77\%$ to $7.48\%$ of the lower bounds.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.249-251
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• 2009

Mobile patrol robots are mainly used in aerospace and military engineering because they can work at dangerous environment replacing a man. This paper presents a study on the remote monitoring and control system of a mobile patrol robot platform using TCP/IP. The mobile robot consists of intel PXA270 and linux-based system. It can get environment information such as images, temperature, humidity and slope by using two cameras and various sensors. And it transmits information data to a monitoring system through the ad-hoc network which is one of wireless network solutions. At this time, a mobile robot is a server and a monitoring system is a client. Users can monitor environment information which is received from a mobile robot by an application based on PC. We have used TCP/IP protocol, socket programming, interface technique of process and devices and control algorithm to embody the mobile robot and its monitoring system. Experimental results shows that the system can be utilized as a remote patrol monitoring tool.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제16권4호
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• pp.65-72
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• 2016

A mobile healthcare application is a healthcare software application designed to run on mobile devices such as smartphone and tablet computers. Mobile healthcare applications have enormous potential for monitoring and care everyday living of patient with chronic disease. In fact, mobile healthcare applications are found to be active in various fields. However, the development is rarely done in Korean medicine field. The aim of this study was to develop the healthcare application based on the tongue diagnosis. The process included planning, designing, programming, and revising. Through a pilot study, the application was found the improvement requirement, and to be usable in the real-life settings.

• Proceedings of the Korea Contents Association Conference
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• 한국콘텐츠학회 2008년도 춘계 종합학술대회 논문집
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• pp.611-613
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• 2008

This paper describes the system that enables users to control the home electronic equipment using mobile phone. The home network industry is setting in network period that grow rapidly and get many interests. And, it is real condition that hailing of existed system is rising too. This paper developed system to make use of mobile phone regarding this and control boiler temperature in home to remote. This paper that serve this used skill of mobile programming, mobile Brew, RF radio communication, etc. for communication with server in an experiment. This paper presented another method that use RF radio communication and mobile device in home automation construction. The result of this paper will be expected to be able to contribute little in development of home network industry.

• Journal of Internet Computing and Services
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• 제10권4호
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• pp.127-138
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• 2009

Mobile web applications are being used and changed rapidly due to the growth of mobile device performance. But, cost of development environment and standards make the high development cost and low productivity. It is main reason that the design and implementation of the applications are more time consuming than general computing environments. In this paper, we propose MWeb(MobileWeb)-Framework based on the agile methodology and Ruby on Rails that is a kind of framework for supporting mobile web application development using mobile web standards. This work consists of the mobile web development architecture and agile process model. MWeb-Framework will support the same user experience to the different devices. We validates the framework by implementing the case studies through suggested mobile web development framework. As a result, we can develop the mobile web applications with productivity and quality. In the future, we will suggest how to make the MWeb-Framework standardization and practically apply the frameworks the various case studies to improve framework potentially problems.

• IEMEK Journal of Embedded Systems and Applications
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• 제12권2호
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• pp.89-96
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• 2017

We develop an embedded system to measure various sensor data, control multiple motors, and communicate with mobile devices for system managements. Choosing TI AM3359 microprocessor featuring high processing performance, low power consumption, and various I/O device support, we design and build the embedded system hardware so that it supports multiple global positioning system (GPS) and gyro sensor modules to measure precise position; multiple pulse width modulation (PWM) outputs to control multiple direct current (DC) motors; a Bluetooth module to communicate with mobile devices. Then, we port the boot loader and device drivers to the built circuit board and construct the firmware development environment for the application programming. The performance of the designed and implemented embedded system is demonstrated by real motor control test using GPS and gyro sensor data and control parameters configured by a mobile device.