• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.17-29
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• 2007

This paper addresses a RNG based scatternet topology formation, self-healing, and routing path optimization for small-scale distributed environment, which is called RNG-FHR(Scatternet Formation, self-Healing and self-Routing path optimization) algorithm. We evaluated the algorithm using ns-2 and extensible Bluetoothsimulator called blueware to show that RNG-FHR does not have superior performance, but is simpler and more practical than any other distributed algorithms from the point of depolying the network in the small-scale distributed dynamic environment due to the exchange of fewer messages and local control. As a result, we realized that even though RNG-FHR is unlikely to be possible for deploying in large-scale environment, it surely can be deployed for performance and practical implementation in small-scale environment.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.6
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• pp.703-714
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• 2001

In C language, a local buffer overflow in stack can destroy control information stored near the buffer. In case the buffer overflow is used maliciously to overwrite the stored return address, the system is exposed to serious security vulnerabilities. This paper analyzes the process of buffer overflow hacking and methodologies to avoid the attacks in details. And it proposes a device of static buffer overflow detection by using function summary and tracking information flow of buffer domain at assembly source code level(SASS, Static Assembly Source code Scanner) and then show the feasibility and validity of it by implementing a prototype in Pentium based Linux environment.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.619-629
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• 2002

This paper describes the implementation of a RTSP-based MPEG-4 streaming system. The implemented system consists of content authoring tool, streaming server and streaming client. The existing MPEG-4 multiplexer has been modified with improvement to generate a file format with which the server load and streaming delay are reduced. The streaming system uses RTSP, instead of DMIF, as its communication protocol. With RTSP, the server provides extensive control functionalities as in DMIF and its implementation effort is greatly simplified. The implemented system supports the user interactivity for both streaming and local file playback. The effectiveness of the proposed multiplexing scheme has been validated with the various experiments on the fully functional server.

• Journal of Internet Computing and Services
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• v.12 no.2
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• pp.1-8
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• 2011

In this paper, we propose an effective method for cooperative spectrum sensing in cognitive radios where cognitive user(CR) with the highest reliability sensing data is only selected and allowed to report its local decision to FC as only decision making node. The proposed scheme enables CR users to implicitly compare their sensing data reliabilities based on their likelihood ratio, without any collaboration among cognitive radio users. Due to the mechanism, the proposed cooperative scheme can achieves a high spectrum sensing performance while only requiring extremely low cooperation resources such as signaling overhead and cooperative time in comparison with other existing methods such as maximum ratio combination (MRC) based, equal gain combination (EGC) based and conventional hard combination based cooperative sensing methods.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.29-36
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• 2019

When dealing with outdoor images in a variety of computer vision applications, the presence of shadow degrades performance. In order to understand the information occluded by shadow, it is essential to remove the shadow. To solve this problem, in many studies, involves a two-step process of shadow detection and removal. However, the field of shadow detection based on CNN has greatly improved, but the field of shadow removal has been difficult because it needs to be restored after removing the shadow. In this paper, it is assumed that shadow is detected, and shadow-less image is generated by using original image and shadow mask. In previous methods, based on CGAN, the image created by the generator was learned from only the aspect of the image patch in the adversarial learning through the discriminator. In the contrast, we propose a novel method using a discriminator that judges both the whole image and the local patch at the same time. We not only use the residual generator to produce high quality images, but we also use joint loss, which combines reconstruction loss and GAN loss for training stability. To evaluate our approach, we used an ISTD datasets consisting of a single image. The images generated by our approach show sharp and restored detailed information compared to previous methods.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.223-231
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• 2007

This paper presents the main business models in ubiquitous city (u-City), the future city strategically integrated with the ubiquitous computing technology. Based on the concept of u-City, the chief services related to the u-City that has been actively developed are analysed, and then the best main four business models (u-Tour, u-ITS, u-SCM and B2B) for SongTan city are presented. The four business models are selected from making an analysis for the present situation of the tour industries, industrial complex, traditional market in SongTan. With the business models, the strategies to realize the active business transactions, high revenues, high value-adding industries, self-sufficient business through the construction of u-City are also presented. Finally, the promoting plans for local autonomy party, citizen party and consortium of industries/universities/researches to give an comfortable u-Life to citizen in SongTan are described.

• Journal of Communications and Networks
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• v.17 no.5
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• pp.506-516
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• 2015

Wireless sensor networks (WSNs) are generally comprised of densely deployed sensor nodes, which results in highly redundant sensor data transmissions and energy waste. Since the sensor nodes depend on batteries for energy, previous studies have focused on designing energy-efficient medium access control (MAC) protocols to extend the network lifetime. However, the energy-efficient protocols induce an extra end-to-end delay, and therefore recent increase in focus on WSNs has led to timely and reliable communication protocols for mission-critical applications. In this paper, we propose an energy efficient and delay guaranteeing node scheduling scheme inspired by biological systems, which have gained considerable attention as a computing and problem solving technique.With the identification of analogies between cellular signaling systems and WSN systems, we formulate a new mathematical model that considers the networking challenges of WSNs. The proposed bio-inspired algorithm determines the state of the sensor node, as required by each application and as determined by the local environmental conditions and the states of the adjacent nodes. A control analysis shows that the proposed bio-inspired scheme guarantees the system stability by controlling the parameters of each node. Simulation results also indicate that the proposed scheme provides significant energy savings, as well as reliable delay guarantees by controlling the states of the sensor nodes.

• Smart Structures and Systems
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• v.17 no.4
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• pp.669-690
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• 2016

Advances in sensor technologies have led to the instrumentation of sensor networks for bridge monitoring and management. For a dense sensor network, enormous amount of sensor data are collected. The data need to be managed, processed, and interpreted. Data management issues are of prime importance for a bridge management system. This paper describes a data management infrastructure for bridge monitoring applications. Specifically, NoSQL database systems such as MongoDB and Apache Cassandra are employed to handle time-series data as well the unstructured bridge information model data. Standard XML-based modeling languages such as OpenBrIM and SensorML are adopted to manage semantically meaningful data and to support interoperability. Data interoperability and integration among different components of a bridge monitoring system that includes on-site computers, a central server, local computing platforms, and mobile devices are illustrated. The data management framework is demonstrated using the data collected from the wireless sensor network installed on the Telegraph Road Bridge, Monroe, MI.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.139-149
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• 1991

In this paper, an efficient method for the ultimate longitudinal strength analysis of the double skin hull girder is presented by using idealized structural unit method. Idealized plate element subjected to biaxial load is developed taking account of initial deflection and welding residual stress. Interaction effect between local and global buckling in the whole structure is also taken into consideration. The reserve strength factor and reliability index for the example 40K double skin product oil carrier are evacuated against the ultimate longitudinal strength. It is concluded that the prudent method seems to be useful in the sense that the computing time required is very short while giving the reasonable solution.

• KIISE Transactions on Computing Practices
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• v.21 no.1
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• pp.40-45
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• 2015

Online social networks(OSN) are very popular nowadays. As OSNs grows, the commercial markets are expanding their social commerce by applying Influence Maximization. However, in reality, there exist more than two players(e.g., commercial companies or service providers) in this same market sector. To address the Influence Maximization problem between adversaries, we first introduced Influence Maximization against the social adversaries' problem. Then, we proposed an algorithm that could efficiently solve the problem efficiently by utilizing social network properties such as Betweenness Centrality, Clustering Coefficient, Local Bridge and Ties and Triadic Closure. Moreover, our algorithm performed orders of magnitudes better than the existing Greedy hill climbing algorithm.