• Journal of Internet Computing and Services
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• v.11 no.6
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• pp.87-110
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• 2010

Recently competitive Korean companies are suffered from financial loss due to illegal exposure of their own proprietary know-how secrets, since it is difficult to watch hidden illegal channels to leak them due to their digitalization. Today the DRM-based system designed to protect such secrets is insufficient to prevent it, since DRM-based protection system cannot defend the intelligent robbery of secrets, in special, employee's robbery. The MSEC is much appropriate to secure secrets against employee's robbery. Our paper notes that IGMP, MSEC and SNMP can work easily together to realize secure system that satisfy strong security condition for prevention from leaking secrets. Since the previous research was on the architectural design for prevention of illegal exposure, this paper proposes the efficient protocol based on MSEC protocol. Our protocol satisfies the strong security conditions that the principles that the secret should be stored/distributed only in an encrypted shape, and should be separated physically from its encryption key, and should be carried in registered mobile storage separate from its processing device, and should be verified in terms of both user and device. Thus this paper proposes both the protocol for secret document distribution and its group key management.

• Journal of Korea Spatial Information System Society
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• v.6 no.2 s.12
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• pp.39-49
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• 2004

An increasing number of distributed applications will be achieved with mobile technology. These applications face temporary loss of network connectivity when they move. They need to discover other hosts in an ad-hoc manner, and they are likely to have scarce resources including CPU speed, memory and battery power. Software engineers building mobile applications need to use a suitable middleware that resolves these problems and offers appropriate support for developing mobile applications. In this paper, we describe the meta-server building for middleware that addresses reflective context awareness and present usability with demonstration. Metadata is consist of user configuration, device configuration, user context, device context and dynamic image metadata. When middleware send a saving or retrieval request to meta-server, it returns messages to middleware after the verification of the request. This meta-server has the application for multimedia stream services with context awareness.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.288-294
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• 2011

In this paper we define the probability models for determining the disparity map given stereo images and derive the methods for solving the problem, which is proven to be equivalent to an energy-based stereo matching. Under the assumptions the difference between the pixel on the left image and the corresponding pixel on the right image and the difference between the disparities of the neighboring pixels are exponentially distributed, a recursive approach for estimating the MRF regularizing parameter is proposed. The proposed method alternates between estimating the parameters with the intermediate disparity map and estimating the disparity map with the estimated parameters, after computing it with random initial parameters. Our algorithm is applied to the stereo matching algorithms based on the dynamic programming and belief propagation to verify its operation and measure its performance.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.4
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• pp.19-25
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• 2002

As computer-related technologies have been developed, legacy design systems have not been appropriate far new computing environment. It is necessary that most of them are either modified or newly developed. However, these activities require quite much amount of cost and time. This paper presents a method of extending legacy design systems to the internet without any modification using XML and XSLT. We have been extended legacy systems in the two viewpoints. First, an XML document has been defined to present the input information of a legacy system which is executed on the consol environment - MS DOS, for example. Also, an XSLT document has been generated to transform an XML document to the input document of the legacy system An XML document is transformed to the input document by XSLT processor according to the transformation rules defined in the XSLT document. This technique to generate input documents is independent to the platform type and facilitates to link legacy systems to other systems. Second, a legacy system controller has been made to control a legacy system and developed a web service to extend it and its controller. The legacy system controller operates it automatically. The web service provides its functions to other systems via internet. We have applied the developed methodologies to the legacy gear design system 조ich calculates AGMA gear rating md made AGMA gem rating web service.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1089-1096
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• 2019

Recently, small-scale IoT services using a small amount of information through low-performance computing have been spread. It requires low cost, low-power, and long-distance communication technologies with wide communication radius, relatively low power consumption. This paper proposes a MAC layer and routing protocol that supports multi-hop transmission in small-scale IoT environment distributed over a large area based on LoRa communication and delivering a small amount of sensing data. The terminal node is mobile and the communication type provides bidirectional transmission between the terminal node and the network application server. By applying the proposed protocol, a production line monitoring system for smart factory was implemented. It was confirmed that the basic monitoring functions are normally performed.

• KIISE Transactions on Computing Practices
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• v.23 no.7
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• pp.434-439
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• 2017

More and more people are suffering from sleep disturbance, which can have many different causes. The healthcare industry, which can help people with this disability, is one technology that is currently in the spotlight. However, current services are vulnerable to data concentration, because they are simple telemedicine services that transmit all data to a remote server and process the data on the server. They have a disadvantage in that the data cannot be streamed in real time by synchronizing the biometric data of remotely protected persons. In order to solve this problem, we propose a service structure for streaming biometric data of protected persons to a hospital or guardian in real time, using a self-organizing distributed middleware platform without a central server. We prove that it is possible to provide an effective streaming service by evaluating the service start time and average delay time.

• KIISE Transactions on Computing Practices
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• v.23 no.10
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• pp.605-610
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• 2017

In distributed environments, dynamic partitioning is needed to resolve the load on a particular server or the load caused by communication among servers. In heterogeneous environments, existing dynamic partitioning schemes can distribute the same load to a server with a low physical performance, which results in a delayed query response time. In this paper, we propose a dynamic partitioning scheme for large RDF data in heterogeneous environments. The proposed scheme calculates the query loads with its frequency and the number of vertices used in the query for load balancing. In addition, we calculate the server loads by considering the physical performance of the servers to allocate less of a load to the servers with a smaller physical performance in a heterogeneous environment. We perform dynamic partitioning to minimize the number of edge-cuts to reduce the traffic among servers. To show the superiority of the proposed scheme, we compare it with an existing dynamic partitioning scheme through a performance evaluation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.147-153
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• 2015

Since the DoS(Denial of Service) attack is still an important vulnerable element in many web service sites, sites including public institution should try their best in constructing defensive systems. Recently, DDoS(Distributed Denial of Service) has been raised by prompting mass network traffic that uses NTP's monlist function or DoS attack has been made related to the DNS infrastructure which is impossible for direct defense. For instance, in June 2013, there has been an outbreak of an infringement accident where Computing and Information Agency was the target. There was a DNS application DoS attack which made the public institution's Information System impossible to run its normal services. Like this, since there is a high possibility in having an extensive damage due to the characteristics of DDoS in attacking unspecific information service and not being limited to a particular information system, efforts have to be made in order to minimize cyber threats. This thesis proposes a method for using TTL (Time To Live) value in IP header to detect DDoS attack with IP spoofing, which occurs when data is transmitted under the agreed regulation between the international and domestic information system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2563-2567
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• 2011

Advances in smart sensors, embedded systems, low-power design, ad-hoc networks and MEMS have allowed the development of low-cost small sensor nodes with computation and wireless communication capabilities that can form distributed wireless sensor networks. Time information and time synchronization are fundamental building blocks in wireless sensor networks since many sensor network applications need time information for object tracking, consistent state updates, duplicate detection and temporal order delivery. Various time synchronization protocols have been proposed for sensor networks because of the characteristics of sensor networks which have limited computing power and resources. However, none of these protocols have been designed with time representation scheme in mind. Global time format such as UTC TOD (Universal Time Coordinated, Time Of Day) is very useful in sensor network applications. In this paper we propose network time protocol extension for global time presentation in wireless sensor networks.

• The KIPS Transactions:PartA
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• v.10A no.6
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• pp.651-656
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• 2003

Emerging technologies, such as multimedia and mobile computing, require that middleware platforms can support high adaptability in order to provide more flexible services in heterogeneous environments. To support high quality of service in distributed wired/wireless environments, it will be necessary for applications and middleware to be aware of changes in users requirements as well as environmental conditions, also to be able to adapt their behaviour as such changes. According to the needs of adaptability supporting in middleware, we structure a component-based, mobile agents framework in base level and meta level by using reflection. We propose concepts of meta agents and meta-service agents that are able to reflect changes made by mobile agents to the system. At the meta level of our framework, meta agents monitor execution of mobile agents and it is possible to provide dynamic adaptation of users requirements, deployment of application services and service customization with meta agents and meta-service agents.