• The KIPS Transactions:PartD
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• v.13D no.1 s.104
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• pp.37-50
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• 2006

In the focusing on the important of wireless internet, mobile terminal device plays a central role in tracking and coordinating terms in mobile business processing. Especially, mobile device has been considered as a key technology for embedded software and ubiquitous era. Because existing web environments is moving to wireless internet, the new concepts for wireless internet computing environments has gained increasing interest. Mobile agents provide a new abstraction for deploying over the existing infrastructures. Mobile application systems require the flexibility, adaptability, extensibility, and autonomous. New software developments methodology is required to meet the requirements. In this paper, we present an agent architectures model that allows compassable components with pluggable and independable. Our approach involves wrapping components inside a servlet. We have used the model and components to develop the PDA mobile agent.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.103-117
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• 2006

This study develops an agent-based simulation model to evaluate tourist information systems under ubiquitous environment. In this study, individual tourist's activity chaining behavior is formulated as a utility maximization problem. The underlying assumption of the model is that tourists increase their activities within their time and budget constraints to maximize their utilities. The model seeks individual's optimal tour schedule by solving Prize-Collecting Multiple-Day Traveling Salesman Problem(PC MD TSP). The simulation-based evaluation framework allows investigating individual utility gains by their information type and the total expenditure at each tour attractions. The real-time tour activity scheduling system enables tourists to optimize their tour activities by minimizing their time loss and maximizing their opportunity to use high utility facilities.

• Journal of Internet Computing and Services
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• v.6 no.5
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• pp.73-83
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• 2005

This paper proposes both a novel tactile human-computer interface method and an improved algorithm for the wearable PC. Under the condition of Ubiquitous computing, the next generation PC aims at effective representation and integration of colors, brightness of light. sound, odor, taste and feelings. Also, it aims at human being centered man-machine interface. In spite of various functions of the wearable PC, for the convenience of possessing, hardware platform for the wearable PC should be small-sized and light weighted one. The main problems of making small sized PC are user interfaces, like keyboard, monitor and so on. The traditional user interfaces have critical limitations for reducing their size. In this paper, we propose a novel user input method and improved algorithm to constructing small sized, light weighted and wearable PC. And, we verify the effectiveness of suggested method and algorithm compared to the traditional algorithm.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.118-127
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• 2009

The current global spread of communal residential culture and the trend of continuing increase of newly built apartment environment are increasing the demand of home network products for each residential space and among households. The continuing advancement of ubiquitous and the introduction and development of home network system are promoting the demand for the product design. The residential culture change and the apartment interior design change are having mutual effects on the lifestyle of residents and the product design and demand new product design. Coordination with interior products, interior style and products, product and fashion design and reconstruction and fusion between the products and their element factors are the core element of this design study. Based on this, integrated design strategy and concept research and analysis were studied for the design process, and have been expressed in three dimension design through which the design functionality and the external aesthetical design can correspond to each other. It's because the aspect of the future development prospect can be predicted in detail by presenting practical design plan.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.548-558
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• 2007

This paper presents a method of location sensing of mobile objects using RF devices. By analyzing signal strengths between a certain number of fixed RF devices and a moving RF device, we can recognize the location of a moving object in real time. Firstly, signal strength values between RF devices are gathered, and then the values are normalized and constructed as a model feature vector for specific location. A number of model patterns are acquired and registered for all of the location which we want to recognize. For location sensing, signal strength information for an arbitrary moving RF device is acquired and compared with model feature vectors registered previously. In this case, distance value is calculated and the moving RF device is classified as one of the known model patterns. Experimental results show that our methods have performed the location sensing successfully with 100% rate of recognition when the number of fixed RF devices is 10 or more than 12. In terms of cost and applicability, experimental results seem to be very encouraging.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.35-41
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• 2010

Since the ad-hoc network allow nodes to communicate each other without infrastructure system and predefined configuration, it comes into the spotlight that is suitable to ubiquitous society. In ad-hoc network, route recovery mechanism is considered important. Normally route recovery is needed to solve the link failure problem because there is no route maintaining system like a router in ad-hoc networks. In this paper we propose BS-AODV(Bidirectional Searching-AODV) route recovery method. The proposed method is a local repair method that can be applied in all of the network area. Unlike a limited local repair method in AODV. the proposed method adopts the bidirectional searching method where the upstream/downstream nodes can send the route maintenance messages. Restricting the flooding of route request messages, the proposed scheme attempts to minimize the costs of local repair, the performance of the proposed scheme is evaluated through the simulations. In two scenarios which variate the node numbers and node speed, the comparison among the proposed scheme, AODV and AOMDV is shown in terms of the control traffic and data delivery ratio.

• The Journal of the Korea Contents Association
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• v.7 no.2
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• pp.51-62
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• 2007

Recently microcontrollers are being used in sensor networks to handle sophisticated control and monitoring activities. As applications become more sophisticated, their design and development processes become more complex which consequently necessitates the use of an operating system to manage the complexity and provide an abstraction for portability of code. This paper presents a Low-power real-time operating system, called UbiFOS-USN, designed for sensor networks. We present some of the features that make UbiFOS-USN appropriate especially for small, low-cost microcontrollers typically found in sensor networks. Through experimental results, we show that UbiFOS-USN is quite efficient for a sensor network, both in terms of system performance and memory requirement.

• Journal of Advanced Navigation Technology
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• v.15 no.1
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• pp.54-60
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• 2011

The development of wireless sensor networks (WSN) can be motivated by several types of applications. However, these applications demand an energy-efficient WSN that can prolong the network lifetime and can provide high throughput, low latency and delay. Designing wireless sensor networks with the capability of prolonging network lifetime catch the attention of many researchers in wireless system and network field. Contrasts with Mobile Ad Hoc Network system, Wireless Sensor Networks designs focused more on survivability of each node in the network instead of maximizing data throughput or minimizing end-to-end delay. In this paper, we will study part of data link layer in Open Systems Interconnection (OSI) model, called medium access control (MAC) layer. Since the MAC development of energy aware MAC Protocol for wireless sensor layer controls the physical radio part, it has a large impact on the overall energy consumption and the lifetime of a node. This paper proposes a analytical approach that tries to reduce idle energy consumption, and shows the increasement of network end-to-end arrival rate due to efficiency in energy consumption from time slot management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.242-246
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• 2005

RFID(Radio Frequency Identification) which is emerging from a change in digital convergence paradigm and recently rapidly advancing throughout the overall society is the core technology based on Ubiquitous network. In other words, This is a technology to identify the information of the object and recognize the situation by attaching electrical tag to an object and using Reader that can read the information of the object. With the emergence of the technology, it has turned the existing maintenance of the product into the network and intelligence of the product control by using the bar cord to maintain the product and will lead a revolution throughout overall society by affecting the fields of distribution and product maintenance as well as those of medicines, chemicals and food which the electrical tag can be attached to. his paper shows that utilizing the Bluetooth which is a local wireless telecommunication in the standalone imbedded system can implement the piconet configuration among the Readers and the data telecommunication with the main server.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1376-1384
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• 2008

Numerous researches on network self-configuration have been conducted on Wireless Sensor Network (WSN) and Ad Hoc network but the results have not been applied yet for factory automation. This paper presents development of intelligent process management systems conducting process monitoring and control irrelevant to physical position of a plant operator. The systems are indispensable for diagnosis of rotating machines which cannot exploit wired network. The system was implemented in a Personal Digital Assistant (PDA) using Bluetooth communication protocol. When a mobile terminal reaches to communication range of the process management server, the server detects the mobile terminal to reconfigure plant network automatically. The server authenticates a user of the terminal to download and installs monitoring and control program considering authorized level of the user. If the terminal leaves communication range of the server, it deletes the node from the network and removes the program automatically to save resources and prevent security problems such as missing terminal. Operation of developed functions was verified in a testbed emulating steel-making plant.