• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.282-291
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• 2008

This paper focuses on message complexity performance analysis of MANET AAPs in reference to link errors generated by the mobile wireless nodes. To obtain the message complexity performance of AAPs in reference to the link error probability ($P_e$), an enhancement was made by proposing the retransmission limit (S) to be computed for error recovery (based on the link error probability), and then for each of the AAPs the control procedures for the retransmission limit have been properly included. The O-notation has been applied in analyzing the upper bound of the number of messages generated by a MANET group of N nodes. Based on a link error probability range of $P_e=0$ to 0.8, the AAPs investigated in this paper are Strong DAD, Weak DAD with proactive routing protocol (WDP), Weak DAD with on-demand routing protocol (WDO), and MANETconf. Based on the simulation results and analysis of the message complexity, for nominal situations, the message complexity of WDP was lowest, closely followed by WDO. The message complexity of MANETconf is higher than that of WDO, and Strong DAD results to be most complex among the four AAPs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1493-1498
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• 2015

The autofocus system is automatically to drive the focus. It is very important to computer vision system. In the case of a compact camera, the actuator technology is used for auto-focus in mass production. the position sensor is required, the circuit configuration and easy method is widely used in VCM, compared to the stability of the drive size and the noise is a big stepping motor type, size has a piezo system having a humidity problem and the small leaded vulnerability. In addition, there is a liquid lens system, the advantages of low power in a compact structure but also a structure with proven quality and reliability and features required pressure. In this paper, we implement two control systems that can control the actuator as a liquid range of VCM using a sharpness of the image acquired by the image sensor automatically initiates 5Mpixel class was the implementation verification of focusing.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.4
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• pp.73-82
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• 2008

Collecting and managing the sensor information through the Internet is critical to effectively manage and utilize the sensor information. The interworking technique of the sensor network and internet is required to realize the desirable condition for managing and utilizing the sensor information. Among many interworking techniques, the translation technique using the gateway had been widely studied. However, the technique which mounts IP-based Internet protocols directly on the sensor node is getting more attention recently. Particularly, IPv6 is suitable for the communication protocol for the sensor network, because its features, such as abundant address space or address auto-configuration, are well matched with the sensor network. In this paper, we design the tiny UDP/IPv6 protocol functions which are suitable for the sensor network environment, and we implemented the functions with TinyOS based nesC. After we examined the simulation results of by using TOSSIM and TinyViz, we carried out the experimental performance evaluation for the program by mounting the tiny UDP/IPv6 on the sensor node (Mote).

• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.12-16
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• 2005

Diesel is one of the best hydrogen systems, which has very high volumetric density $[kg\;H_2/m^3]\;(>100)\;and\;gravimetric\;density[\%\;H_2]\;(>\;15)$Several catalysts were selected for diesel reforming. 3 catalysts of our group (NECS-1, NECS-2, NECS-3) and 2 commercial catalysts (Sud-Chemie, Inc, FCR-HCl4, FCR-HC35) were used to reform diesel. NECS-1 showed the best performance to reform diesel. In addition to these results, we studied on reaction characteristics for better understanding about auto thermal reforming of diesel by investigating product gas concentrations and temperature Profiles along the catalyst bed. We found technological issues such as fuel delivery and thermal configuration between front exothermic part and rear endothermic part.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.30-38
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• 1998

A new frequency weighing sensor was applied to grow Bi12GeO20 crystals in the auto-di-ameter control system of Czochralski method. The rotation rate was varied in the range of 23 to 21 rpm to preserve flat interface in a given heat configuration. To prevent the constitutional super-cooling from the evaporation loss, 105% stoichiometric amount of Bi2O3 was employed, equivalent to 6.18 molar ratio of Bi2O3 to GeO2. Transparent and light brown Bi12GeO20 single crystal in uniform diameter was grown. The dislocation density was determined to be 103/cm2 corresponding to the optical quality in commercial applications. The grown crystal measured diameter 25 mm and length 70 mm and the preferred growth direction was confirmed to be <110>.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.37-48
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• 2011

Synthetic Aperture Radar(SAR) is a powerful and well established microwave remote sensing technique which enables high resolution measurement of Earth surface independent of weather conditions and sunlight illumination. KARI has been developing the first Korea SAR satellite which is scheduled to be launched in this year. The SAR satellite mainly consists of the bus platform and SAR payload. Most of all, the RF compatible design during the design phase and the verification of the RF compatibility during the testing phase is very important procedure for the in-orbit performance guarantee because the SAR payload radiates high power through the SAR antenna. In this study, the SAR satellite design criteria and verification procedure for the RF compatibility are described. In addition, this paper describes the RF full radiation testing (RF auto-compatibility testing) for the verification of the RF performance robustness, the testing configuration, and the test results.

• Journal of Korea Multimedia Society
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• v.12 no.8
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• pp.1099-1108
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• 2009

The study of IP address allocation in MANET can be categories into Stateful and Stateless. The one, special node monitors other nodes' IP address and allocates IF address. And the other, node generates IP address by itself. Nodes in MANET have mobility and restricted resource, so Stateless is more suitable than Stateful. But, in Stateless, node requires DAD process because of unique IP address allocation. And Dos attack can be happened in DAD precess. In this paper, we propose a security method on preventing DoS attack against DAD in MANET using one-way hash function. Since, Computation of one-way hash function is suitable for nodes' restricted resource character in MANET. And we evaluate performance using NS2 and compare with other security method which is CGA using signature.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.891-892
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• 2016

Recent research has become a smart home for operating the joining operation of the relationships between the device progress. However, Existing systems, there is a problem that the efficiency of the work can be degrade by the interference occurs when the operation of the other device, and triggered if the device is operating. In this paper, we designed a priority automatically set algorithm according to a user selection device to solve this problem. The user selects the device used by the application and by comparing between devices, select whether or not to set the priority of the tasks in. This allows the user can configure the working environment of only the desired device, and less chance of interference from other devices that are not selected during the work in progress can expect a more efficient productivity.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.105-117
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• 2019

Current Android smartphones include about 25 to 35 essential applications(unerasable) related to function and operation of the android smartphone itself and about 30 optional applications(removable) provided by carriers, Google and manufacturers. These applications were not able to be removed until the announcement of the smartphone applications pre-install guide from the government in January 2014, so there were memory limitations in installing new applications, causing consumer complaints by consuming data during the auto-update process of the pre-installed applications. After the announcement, we were able to delete optional applications but the complaints about the data consumption still did not disappear. Therefore, in this paper, we carried out the customer survey and analyzed the behavior information such as how carriers are operating pre-installed applications and what kind of applications customer prefers and how many applications customer wants to be pre-installed. And we proposed how to configure pre-install applications on smartphone for customer needs.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.226-238
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• 2007

In this paper, we present a novel fully distributed topology control protocol that can construct the multiple-ring topology of Minimal Connected Dominating Set (MCDS) as the transport backbone for mobile ad hoc networks. It makes a topology from the minimal nodes that are chosen from all the nodes, and the constructed topology is comprised of the minimal physical links while preserving connectivity. This topology reduces the interference. The all nodes work as the nodes of the distributed parallel Boltzmann machine, of which the objective function is consisted of two Boltzmann factors: the link degree and the connection domination degree. To define these Boltzmann factors, we extend the Connected Dominating Set into a fuzzy set, and also define the fuzzy set of nodes by which the multiple-ring topology can be constructed. To construct the transport backbone of the mobile ad hoc network, the proposed protocol chooses the nodes that are the strong members of these two fuzzy sets as the clusterheads. We also ran simulations to provide the quantitative comparison against the related works in terms of the packet loss rate and the energy consumption rate. As a result, we show that the network that is constructed by the proposed protocol has far better than the other ones with respect to the packet loss rate and the energy consumption rate.