• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.34-41
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• 2009

This paper investigates the issue of efficient reading for sensor data of semi-passive sensor tag. The Cold Chain management system requires complete sensor data without data loss and the short processing time of reading sensor tag data. However, reading the sensed data could be interfered by RF environment such as a jamming, obstacle and so on. This study found that it could lead to loss of the sensed data and takes much time to read it when data loss is occurred. To solve this problem, we propose the transaction processing mechanism that guarantees efficient reading of the sensed data. To do this, we present the technique of dynamic packet size and technique of data recovery to execute read transaction. These techniques improve the reliability of reading operation as well as speed up of read process for the large capacity data. This paper contributes to the improvement of efficient reading of sensed data without any loss of data and large time required.

• Journal of KIISE
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• v.44 no.3
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• pp.261-274
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• 2017

Variability management is the foremost criterion that defines the extent to which complexities can be handled in a system. Predominantly, the requirements' engineering (RE) study overlooks, or speculates a consistent behavior of, the environment in which a system functions. In real-time systems it is vital to observe and adjust to an intrinsically changing context. Therefore, in this work we identify the requirements of the system in various contexts by recommending a framework using i* goal model, problem frames, use case maps and live sequence charts. The framework is illustrated using a case study of the smart grid RTP system. In the case study, elaboration of scenarios using use case maps and live sequence charts proved beneficial as they assisted in early analysis and validation of contexts. In addition, the elaboration of requirements for obstacle and conflict analysis assists the requirements engineer to increase the robustness of the system. The proposed framework is evaluated theoretically and by empirical study.

• Journal of Internet Computing and Services
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• v.4 no.2
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• pp.1-9
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• 2003

Path restoration, which is needed to increase network survivability in MPLS networks, is a technology of supplying reliable service by delivering the traffics through restoring the paths when links or nodes of a working path are failed. In this paper, we propose a path restoration method using duplication of working paths for link failure as a method of restoring paths for the high priority traffics. The existing path restoration method transmits the traffics to the path restoration uniformly in regardless of the priority while link obstacle. It has a problem to take a long time to restore the connection of the high priority traffics. On the other hand, the suggested restoration method establishes the duplication path for the working path, which transmits the high priority traffics and transmit the traffics through the duplication path. It has a strong point to restore the connection quickly. Also, through simulation we analyze the performance of the restoration system using the duplication path and prove that the proposed restoration method is superior in performance to the existing restoration methods regarding to the high priority traffics.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.599-604
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• 2008

Recently, many researches for autonomous mobile system have been proposed, which can recognize surrounded environment and navigate to destination without outside intervention. The basic sufficient condition for the autonomous mobile system is to navigate to destination safely without accident. In this paper, we propose a path planning method in local region for safe navigation of autonomous system through evaluation of the road surface distortion(damaged/deformed road, unpaved road, obstacle and etc.). We use laser distance sensor to get the information on the road surface distortion and apply image binalization method to evaluate safe region in the detected local region. We show the validity of the proposed method through the computer simulation based on the artificial local road map.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.108-116
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• 2008

In this paper, we propose an algorithm that can estimate the distance using disparity based on stereo vision system, even though the obstacle is located in long ranges as well as short ranges. We use sub-pixel interpolation to minimize quantization errors which deteriorate the distance accuracy when calculating the distance with integer disparity, and also we use enhanced adaptive fuzzy strong tracking Kalman filter(EAFSTKF) to improve the distance accuracy and track the path optimally. The proposed method can solve the divergence problem caused by nonlinear dynamics such as various vehicle movements in the conventional Kalman filter(CKF), and also enhance the distance accuracy and reliability. Our simulation results show that the performance of our method improves by about 13.5% compared to other methods in point of root mean square error rate(RMSER).

• Korean Institute of Interior Design Journal
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• v.27 no.1
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• pp.156-164
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• 2018

This study analyzed the characteristics of Physical Environment of existing free shuttle bus Interior centered on elderly people who frequently use free shuttle buses. The purpose of this study is to provide basic data that can be used for improvement of existing free shuttle buses. In the case of the old type, in terms of accessible design, the middle entrance is not normally opened except the wheelchair occupant, so that the entrance of the front wheel is always used. Therefore, most elderly people go to the back seat and travel distance is twice longer. In addition, many stairs caused frequent inconveniences for boarding. In the case of the new type, it is planned to be a low-floor type, and various types of safety rods and handles, pictograms for enhancing the information convenience are well-equipped, and the measured value of the overall design characteristic is high. However, in the case of mental stability, it was confirmed that the seat of the bus is colored with a cold color system and is in a different relationship with the warm color which can feel mental stability. Overall, both old and new shuttle buses lack audiovisual feedback on bus routes and route guidance in terms of Supportive design. Also, since the cleaning tools and other miscellaneous items were left in the room, it became an obstacle to space utilization in terms of adaptable design. In terms of safety, both shuttle buses did not come into view with fire extinguishers shaded by miscellaneous items. Therefore, immediate action is unlikely in case of emergency. This problem should be resolved quickly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.160-166
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• 2018

This paper proposes an advanced suspension system and reports its performance in the framework of the preview control algorithm based on the RPS (road profile sensing) system and MSD system with the multi-stage damping characteristics. Typical disturbance inputs that cause excessive vibration and steering instability of an automobile are irregular obstacles that protrude or sink into the road surface to be driven. The control performance can be improved if information on the existence and shape function of its obstacle is known. Based on the results of the previous study, advanced research that uses the actuating system has been processed to be commercialized practically. For this purpose, a switching algorithm between the control logic and the multi-stage damping system was developed and its connectivity is presented. To verify the applicability of an actual vehicle, the proposed control system was implemented in full vehicle models and simulations were performed. The proposed system using the 3-DS actuator system, which is applied for structural simplicity, can improve the ride comfort and steering stability. In addition, the results indicate the feasibility of the intelligently controlled suspension system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.696-702
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• 2010

In many industrial applications, it is very important to control the temperature of the controlled object to the target temperature as closely as possible. Although it is apparent that the great obstacles in controller design are time-delay of the thermal responses of the controlled object and the effect of thermal interference between neighboring heating zones, one more fundamental obstacle is a very large amount of time which is required during repeated experiments in controller design process. Therefore, a convenient simulation environment, which can represent thermal behavior accurately within appropriate time, is needed. In this paper, a prototype of 2D FEM (finite element method) heat transfer simulation environment using MATLAB is constructed to be usefully adopted into industrial applications with temperature controller design.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.76-80
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• 2017

With the fast growing popularity of small UAVs (Unmanned Aerial Vehicles), recent UAV systems have been designed and utilized for the various field with their own specific purposes. UAVs are opening up many new opportunities in the fields of electronics, sensors, camera, and software for pilots. Increase in awareness and mission capabilities of UAVs are driving innovations and new applications driven with the help of low cost and its capability in undertaking high threat task. In particular, small unmanned aerial vehicles should fly in environments with high probability of unexpected sudden change or obstacle appearance in low altitude situations. In this paper, current researches regarding techniques of autonomous flight of smal UAV systems are introduced and we propose a draft idea for planning paths for small unmanned aerial vehicles in adversarial environments to arrive at the given target safely with low cost sensors.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.6
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• pp.34-42
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• 2011

With the progress of USN technology, fields to which wireless sensor node is applicable are increased under a condition that it holds a lot of problems to solve for betterment. One of the problems which acts as an obstacle to USN industry diffusion is the wireless sensor node battery exchange to their individual life cycle. Exchanging the battery of so many sensor nodes one by one requires a great deal of times and costs. Such problem is against the convenience supply -aim by applying USN technology. In this paper, using RF wireless power transmission system that power transmission / harvesting module from a distance of 5 m and the power of 10 dBm with a current of 1 mA or more for Sensor Nodes in lithium-polymer battery charging system tested and verified.