• Journal of Digital Convergence
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• v.15 no.3
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• pp.187-193
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• 2017

Objects Internet-based healthcare services provide healthcare and healthcare services, including measurement of user's vital signs, diagnosis and prevention of diseases, through a variety of object internet devices. However, there is a problem that new security vulnerability can occur when inter-working with the security weakness of each element technology because the internet service based on the object Internet provides a service by integrating various element technologies. In this paper, we propose a user privacy protection model that can securely process user's healthcare information from a third party when delivering healthcare information of users using wearable equipment based on IoT in a mobile environment to a server. The proposed model provides attribute values for each healthcare sensor information so that the user can safely handle, store, and store the healthcare information, thereby managing the privacy of the user in a hierarchical manner. As a result of the performance evaluation, the throughput of IoT device is improved by 10.5% on average and the server overhead is 9.9% lower than that of the existing model.

• The Korean Journal of Applied Statistics
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• v.27 no.2
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• pp.249-261
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• 2014

Ever increasing "Big data" can only be effectively processed by parallel computing. Parallel computing refers to a high performance computational method that achieves effectiveness by dividing a big query into smaller subtasks and aggregating results from subtasks to provide an output. However, it is well-known that parallel computing does not achieve scalability which means that performance is improved linearly by adding more computers because it requires a very careful assignment of tasks to each node and collecting results in a timely manner. Hadoop is one of the most successful platforms to attain scalability. In this paper, we propose a measurement for Hadoop optimization by utilizing a Lorenz curve which is a proxy for the inequality of hardware resources. Our proposed index takes into account the intrinsic overhead of Hadoop systems such as CPU, disk I/O and network. Therefore, it also indicates that a given Hadoop can be improved explicitly and in what capacity. Our proposed method is illustrated with experimental data and substantiated by Monte Carlo simulations.

• Journal of Communications and Networks
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• v.12 no.1
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• pp.52-66
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• 2010

Since large objects consume substantial resources, web proxy caching incurs a fundamental trade-off between performance (i.e., hit-ratio and latency) and overhead (i.e., resource usage), in terms of caching and relaying large objects to users. This paper investigates how and to what extent the current dedicated-server based web proxy caching scheme is affected by large file transfers in a high bandwidth campus network environment. We use a series of trace-based performance analyses and profiling of various resource components in our experimental squid proxy cache server. Large file transfers often overwhelm our cache server. This causes a bottleneck in a web network, by saturating the network bandwidth of the cache server. Due to the requests for large objects, response times required for delivery of concurrently requested small objects increase, by a factor as high as a few million, in the worst cases. We argue that this cache bandwidth bottleneck problem is due to the fundamental limitations of the current centralized web proxy caching model that scales poorly when there are a limited amount of dedicated resources. This is a serious threat to the viability of the current web proxy caching model, particularly in a high bandwidth access network, since it leads to sporadic disconnections of the downstream access network from the global web network. We propose a peer-to-peer cooperative web caching scheme to address the cache bandwidth bottleneck problem. We show that it performs the task of caching and delivery of large objects in an efficient and cost-effective manner, without generating significant overheads for participating peers.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.772-775
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• 2008

According to Korean Ministry of Land, Transportation and Maritime Affairs, total national SOC(Social Overhead Capital) stock comes up to 500 billion dollars. Until now, although the construction of SOC is more important than the maintenance of them in Korea, it is necessary to introduce of valuation based total asset management concept in nowadays. In this paper describes problems of exsiting data collection method, needs of Information Technology and introduction of RFID/USN(Radio Frequency IDentification/Ubiquitous Sensor Network) in data collection stage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5D
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• pp.463-472
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• 2012

Exemplary contracts of construction management (CM) including highway projects have been carried out in the civil engineering area over the past ten years. However, practical and administrative challenges as transitional circumstances have been revealed in the different participants of supervision, inspection and construction management. Thus, it is important to internally overcome problems and negative perception encountered in civil engineering, and to promote the efficiencies in construction cost and quality. In addition, external efforts should be put to market opening, globalization, and technology development for competitiveness and high value industry. While it is critical to establish the concrete CM system by collaborating with various participants, proven architecture and system have not been provided because of incorrect measurement of CM accomplishment, overlap of responsibility between CM and supervision, and slow deployment in construction field. This paper analyzed the current CM practices and business environments, and presented the possible solutions for strategy improvement of CM in the owner's view point.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.403-408
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• 2010

The sensor nodes can be installed in the environment in which the temperature change is considerable, such as desert, urban, and data center. Particularly, because the output power becomes less than the targeted power if a temperature is increasing, link quality is degraded and packet losses are occurred. In order to compensate the temperature changes, existing schemes detect the change of the link quality between nodes and control transmission power through a series of feedback process. However, these approaches can cause heavy overhead by additional control packets. In this paper, we propose the T2PC(Temperature-aware Transmission Power Control) to keep up the link quality despite temperature variation. At each node, T2PC compensates the attenuated link quality by controlling the transmission power based on the local temperature measurement. In addition, the packet reception ratio can be improved with less control packets than ones required in existing transmission power control methods based on the feedback control.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.955-963
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• 2022

The Internet of Things (IoT), combined with various technologies, is rapidly becoming an integral part of our daily life. While it is rapidly taking root in society, security considerations are relatively insufficient, making it a major target for cyber attacks. Since all devices in the IoT environment are connected to the Internet and are closely used in daily life, the damage caused by cyber attacks is also serious. Therefore, encryption communication using a network security protocol must be considered for a service in a more secure IoT environment. A representative network security protocol includes TLS (Transport Layer Protocol) defined by the IETF. This paper analyzes the performance measurement results for TLS version 1.2 and version 1.3 in an IoT device open platform environment to predict the load of TLS, a representative network security protocol, in IoT devices with limited resource characteristics. In addition, by analyzing the performance of each major cryptographic algorithm in version 1.3, we intend to present a standard for setting appropriate network security protocol properties according to IoT device specifications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2334-2339
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• 2009

In case of an embedded system having an LCD panel with touch-screen capability, various figures such as rectangles, pentagons, circles, and arrows are frequently used for the delivery of user-input commands. In such a case, it is necessary to have an algorithm that can recognize whether a touched location is within a figure on which a specific user-input command is assigned. Such algorithms, however, impose a considerable amount of overhead for embedded systems with restricted amount of computing resources. This paper first describes a method for initializing and driving a touch-screen LCD and a coordinate-calibration method that converts touch-screen coordinates into LCD panel coordinates. Then it introduces methods that can be used for recognizing touched areas of rectangles, many-sided figures like pentagons, and circles; they are a range checking method for rectangles, a crossing number checking method for many-sided figures, a distance measurement method for circles, and a color comparison method that can be applied to all figures. In order to evaluate the performance of these methods, we implement two-dimensional graphics functions for drawing figures like triangles, rectangles, circles, and images. Then, we draw such figures and measures times spent for the touched-area recognition of these figures. Measurements show that the range checking is the most suitable method for rectangles, the distance measurement for circles, and the color comparison for many-sided figures and images.

• Journal of the Korean Geosynthetics Society
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• v.23 no.2
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• pp.43-52
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• 2024

Recent abnormal climate conditions have increased the risk of slope collapses, which frequently result in significant loss of life and property due to the absence of early prediction and warning dissemination. In this paper, we develop a slope condition analysis system using IoT sensors and AI-based camera to assess the condition of slopes. To develop the system, we conducted hardware and firmware design for measurement sensors considering the ground conditions of slopes, designed AI-based image analysis algorithms, and developed prediction and warning solutions and systems. We aimed to minimize errors in sensor data through the integration of IoT sensor data and AI camera image analysis, ultimately enhancing the reliability of the data. Additionally, we evaluated the accuracy (reliability) by applying it to actual slopes. As a result, sensor measurement errors were maintained within 0.1°, and the data transmission rate exceeded 95%. Moreover, the AI-based image analysis system demonstrated nighttime partial recognition rates of over 99%, indicating excellent performance even in low-light conditions. Through this research, it is anticipated that the analysis of slope conditions and smart maintenance management in various fields of Social Overhead Capital (SOC) facilities can be applied.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.658-673
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• 2018

Social conflicts with extremely low frequency magnetic field(ELF-MF) exposures are expected to exacerbate due to continued increase in electric power demand and construction of high voltage transmission lines(HVTL). However, in current environmental impact assessment(EIA) act, specific guidelines have not been included concretely about EIA of ELF-MF. Therefore, this study conducted a standardization study on EIA method through case analysis, field measurement, and expert consultation of the EIA for the ELF-MF near HVTL which is the main cause of exposures. The status of the EIA of the ELF-MF and the problem to be improved are derived and the EIA method which can solve it is suggested. The main contents of the study is that the physical characteristics of the ELF-MF affected by distance and powerload should be considered at all stages of EIA(survey of the current situation - Prediction of the impacts - preparation of mitigation plan ? post EIA planning). Based on this study, we also suggested the 'Measurement method for extremely low frequency magnetic field on transmission line' and 'Table for extremely low frequency magnetic field measurement record on transmission line'. The results of this study can be applied to the EIA that minimizes the damage and conflict to the construction of transmission line and derives rational measures at the present time when the human hazard to long term exposure of the ELF-MF is unclear.