• Journal of information and communication convergence engineering
• /
• v.9 no.2
• /
• pp.166-171
• /
• 2011

This paper investigates the design issues of spectrum sensing in the cognitive radio (CR) networks of opportunistic unlicensed spectrum access. The cognitive radios can perform a communication using the incumbent user spectrum band without the interference caused by the cognitive radio users. In this case, the cognitive radios must know the real-time radio environments of the incumbent user spectrum band using the spectrum sensing, beacon signal, and geo-location database access. Then in this paper, we are going to provide spectrum sensing issues which include the sensing techniques, the regulatory requirements, the analysis of DTV detection threshold, and main considerations associated with the spectrum sensing design in cognitive radio systems. Also, this paper introduces design trade-offs in order to optimize the sensing parameters such as sensing time and sensing complexity.

• Proceedings of the KSRS Conference
• /
• 2008.10a
• /
• pp.266-269
• /
• 2008

Urban is more intelligent continuously with the help of the convergence with IT technology. And it requires an integrated control system, which can manage urban facilities or monitor large-scale events based on GIS data, to provide its citizen with various ubiquitous services such as u-Health, u-Traffic, context-awareness etc. In order to realize the intelligent city geo-sensors that have the functionalities of generic sensing as well as location awareness will be established everywhere in the near future. Our system we presented have a rule engine to handle a atomic event as well as complex events that contain control flow or branch among them. And it can allow for visualization and monitoring the results through KML (Keyhole Mark-up Language) in the Google Maps. This paper describes au-GIS event processing system that can deal effectively with u-GIS events coming from various geo-sensor data in ubiquitous computing environments.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.9 no.1
• /
• pp.53-59
• /
• 2014

In multiple object tracking, accurate detection for each of objects that appear sequentially and effective tracking in complicated cases that they are overlapped with each other are very important. In this paper, we propose a multiple object tracking system that has a concrete detection and tracking characteristics by using multi-lateral histogram and SIFT feature extraction algorithm. Especially, by limiting the matching area to object's inside and by utilizing the location informations in the keypoint matching process of SIFT algorithm, we advanced the tracking performance for multiple objects. Based on the experimental results, we found that the proposed tracking system has a robust tracking operation in the complicated environments that multiple objects are frequently overlapped in various of directions.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1729-1730
• /
• 2008

In the industry, the automation of brazing system is very important using the vision senor and the edge detection of the bronze pipe. And also, the accurate coordination is needed for the finding of the precise location. In this paper, we propose an algorithm for the measurement of 3D information of the brazing material and the detection algorithm of soldering area using the camera and IR sensor. We use Canny edge detector in noisy environments. The experimental study shows that camera and IR sensor is useful for the measurement of distance in the brazing work.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.67-72
• /
• 2000

Demand for now nondestructive evaluation are growing to detect fatigue crack growth behavior to predict long term performance of materials and structure in aggressive environments especially when they are In non-visible area. Acoustic emission technique is well suited to these problems and has drawn a keen interests because of its dynamic detection ability, extreme sensitivity and location of growing defects. In this study, we analysed acoustic emission signals obtained in fatigue and tensile test of high strength fire resistance steel for frame structure with time-frequency analysis methods. The main frequency range is different in the noise and the fatigue crack propagation. It could be classified that it were also generated by composite fracture mechanics of cleavage, dimple, inclusion separation etc.

• Journal of the Korean Home Economics Association
• /
• v.40 no.9
• /
• pp.191-205
• /
• 2002

The purpose of this study is to identify the homelike design characteristics of elderly housing facility. To investigate what the preference of physical design characteristics are, interview was done by unstructured questionnaire to 30 middle aged and middle income group housewives living in Seoul. It was identified that preferred homelike physical characteristics of the houses were composed of 4 themes, housing types, building appearences and garden, floor plan and natural and social environments of its location. Their desirable housing standard was amenity which is the highest level of home environment. In their later life, they wanted to live in vicinity of Seoul to enjoy cultural benefits of the city and active outdoor activities in sunny, natural suburban environment. They liked a spacious, clean and bright color with natural material furnishings. Each architectural design expression of 4 themes was suggested.

• Journal of Korea Multimedia Society
• /
• v.19 no.8
• /
• pp.1597-1608
• /
• 2016

Recently, a number of solutions were proposed to address the challenges and issues of vehicular networks. Vehicular Cloud Computing (VCC) is one of the solutions. The vehicular cloud computing is a new hybrid technology that has a remarkable impact on traffic management and road safety by instantly using vehicular resources. In this paper, we study an important vehicular cloud service, content-based delivery, that allows future vehicular cloud applications to store, share and search data totally within the cloud. We design a VCC-based system architecture for efficient sharing of vehicular contents, and propose a Hierarchical Hybrid Content Delivery scheme using Bloom Filter (H2CDBF) for efficient vehicular content delivery in Vehicular Ad-hoc Networks (VANETs). The performance of the proposed H2CDBF is evaluated through an analytical model, and is compared to the proactive content discovery scheme, Bloom-Filter Routing (BFR).

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.8
• /
• pp.1255-1258
• /
• 2022

Recently, immersive VR/AR contents have actively increased, and various services related to VR/AR allow users to experience remote places. For example, if failure situations occur frequently in factory of the remote site, mixed reality (MR) with a synthetic virtual human expert in reconstructed remote location can help immediate maintenance task with interaction between the operator and the virtual expert. In this paper, we present a technique for synthesizing the virtual human after capturing a 360-degree panorama of a remote environment, and analyze the effects to apply a method of guiding virtual human by interaction types. According to this paper, it was shown that co-presence level significantly increased when verbal, facial expression, and non-verbal animation of the virtual human was all expressed.

• Journal of Industrial Technology
• /
• v.25 no.B
• /
• pp.211-220
• /
• 2005

The wireless sensor network consists of a number of sensor nodes which have physical constraints. Each sensor node senses surrounding environments and sends the sensed information to Sink. The inherent vulnerability in security of the sensor nodes has promoted the needs for the lightweight security protocol. In this paper, we propose a non-hierarchical sensor network and a security protocol that is suitable for monitoring the man-made objects such as bridges. Furthermore, we present the efficient way of setting the routing path by storing IDs, MAC(message authentication code) and the location information of the nodes, and taking advantage of the two node states, Sleep and Awake. This also will result in the reduced energy consuming rate.

• Industrial Engineering and Management Systems
• /
• v.6 no.2
• /
• pp.125-135
• /
• 2007

An automated guided vehicle (AGV) system is a group of collaborating unmanned vehicles which is commonly used for transporting materials within manufacturing, warehousing, or distribution systems. The performance of an AGV system depends on the dispatching rules used to assign vehicles to pickup requests, the vehicle routing protocols, and the home location of idle vehicles, which are called dwell points. In manufacturing and distribution environments which emphasize just-in-time principles, performance measures for material handling are based on response times for pickup requests and equipment utilization. In an AGV system, the response time for a pickup request is the time that it takes for the vehicle to travel from its dwell point to the pickup station. In this article, an exact dynamic programming algorithm for selecting dwell points in a tandem-loop multiple-vehicle AGV system is presented. The objective of the model is to minimize the maximum response time for all pickup requests in a given shift. The recursive algorithm considers time restrictions on the availability of vehicles during the shift.