• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.99-107
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• 2002

Broadcast disks are suited for disseminating information to a large number of clients in mobile computing environments. In broadcast disks, the server continuously and repeatedly broadcasts all data items in the database to clients without specific requests. The clients monitor the broadcast channel and retrieve data items as they arrive on the broadcast channel. The broadcast channel then becomes a disk from which clients can retrieve data items. In this paper, we propose a cache conscious concurrency control ($C^4$) scheme to preserve the consistency of client transactions, when the values of broadcast data items are updated at the server. $C^4$ scheme is novel in the sense that it can reduce the response time of client transactions with minimal control information to be broadcast from the server. This is achieved by the judicious caching strategy of the clients.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1573-1581
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• 1996

This paper present as experimental demonstratio of DSP and a sensory actuator that is used to actively control sound transmission/radiation through a vibrating plate. A plane acoustic wave incident on a clamped, thin circular plate was used as a noise source, and a sensory actuator bounded to the plate was used to control and sense vibration of the plate. The sound transmission reduction problem was tranformed as a structural vibration control problem that actively control the structural vibration modes coupled to acoustic modes. The results show that the first structural vibration mode is controlled with a reduction of 78 percent in the displacement and velocity of the plate. This corresponds to a 13dB reduction in the acoustic response. These experimental results indicate that a sensory actuator bounded to the plate can be employed to attenuate the sound transmitted to radiated from the plate.

• Molecules and Cells
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• v.24 no.2
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• pp.247-254
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• 2007

Improvement in the pharmacokinetic properties of short interfering RNAs (siRNAs) is a prerequisite for the therapeutic application of RNA interference technology. When injected into mice as unmodified siRNAs complexed to DOTAP/Chol-based cationic liposomes, all 12 tested siRNA duplexes caused a strong induction of cytokines including interferon ${\alpha}$, indicating that the immune activation by siRNA duplexes is independent of sequence context. When modified by various combinations of 2'-OMe, 2'-F, and phosphorothioate substitutions, introduction of as little as three 2'-OMe substitutions into the sense strand was sufficient to suppress immune activation by siRNA duplexes, whereas the same modifications were much less efficient at inhibiting the immune response of single stranded siRNAs. It is unlikely that Toll-like receptor 3 (TLR3) signaling is involved in immune stimulation by siRNA/liposome complexes since potent immune activation by ds siRNAs was induced in TLR3 knockout mice. Together, our results indicate that chemical modification of siRNA provides an effective means to avoid unwanted immune activation by therapeutic siRNAs. This improvement in the in vivo properties of siRNAs should greatly facilitate successful development of siRNA therapeutics.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.5
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• pp.19-24
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• 1978

In this paper, the functional propertied of vibrotactile sense of skin were studied by means of psycophysical experiments with respect to frequency and waveform of mechanical vibration, two-point threshold, contactor size of stimulators. Furthermore, leased on the experimental result, a small vibrotactile stimulator made of piezoelectrc ireed vibrator array was proposed for a aid blind to recognition of the Korean letters. A tactile output image is presented by an 8 row$\times$1 column array of samall vibrator reeds with 200 Hz rectangular wave, the array fitting on a fore-finger. Under the control of the NOVA mini-computer, the bimorph reeds array could represent any of one of the 24 characters of the Korean vowel and consonant at the 8 positions from left to right on the array. Without learning effect, the identification test of the Korean characters by the designed experimental system was carried out. The average rate of correct response was 90%.

• The Journal of Korea Robotics Society
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• v.8 no.3
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• pp.156-163
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• 2013

This paper describes a flexible visuo-haptic display module. We have developed a flexible electro-active polymer (EAP) actuator and a thin flexible visual display with $3{\times}3$ array configuration via polymer technology. The flexible actuator consists of nine EAP cells vertically moving in response to change in their thickness. The flexible display uses polymer based optical waveguide allowing light to scatter only at specific area. The display film is transparent and identically designed to the array pattern to fit for the arrangement of actuator cells. A pressure sensor is installed under the integrated module. The performance of the actuator is proved to be sufficient for satisfying perceivable range of human touch sense. The integrated system can provide interactive haptic feedback such as key pressing, contact vibration sensations, and etc. in accordance with user input.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.399-407
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• 1998

This paper deals with a method for finding the physical structure of dynamic systems which shows reasonable response to a given specifiation. The method uses only four basic models of bond graph prototypes which have been originally proposed by the authors as a general model for dynamic systems, and then makes its procedure highly physical in the sense that it can synthesize a dynamic system through the structural transformation directly on bond graph models without any mathematical manipulation. Also, it is shown that this method has further advantages in optimizing parameters for an existing system rather than developing design concepts for a new device, the latter being more suitable using the so-called analytical synthesis method introduced by Park and Redfield. One example serves to trace the outlines of the direct synthesis method proposed in this paper for dynamic systems in terms of bond graph prototypes.

• Journal of the military operations research society of Korea
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• v.32 no.2
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• pp.165-187
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• 2006

The aim of this study is to suggest the direction of implementing the new defense logistics systems for the network centric warfare in the future. For this purpose, we reviewed SARL(Sense and Response Logistics) which receives great attention from the U.S. Department of Defence as the future logistic concept of network centric warfare, coupled with recent development in information technologies which give technical revolution in the future logistics information system. Also, we analyzed problems underlying logistics information system currently used in the Korean Armed Forces. Finally, we suggested the direction of implementing the new logistics information system for the network centric warfare, expecting to reduce total logistics cost, speed up logistics velocity, and enhance the efficiency of the combat support.

• The Journal of Korean Institute for Practical Engineering Education
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• v.5 no.1
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• pp.34-39
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• 2013

This paper suggests an input device that allows a user not only to naturally interact with education contents in virtual environment but also to sense haptic feedback according to his/her interaction. The proposed system measures a user's motion and then creates haptic feedback based on the measured position. To create haptic information in response to a user's interaction with educational contents in virtual environment, we develop a motion input device which consists of a motion controller, a haptic actuator, a wireless communication module, and a motion sensor. To measure a user's motion input, an accelerometer is used as the motion sensor. The experiment shows that the proposed system creates continuous haptic sensation without any jerky motion or vibration.

• Journal of Korea Port Economic Association
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• v.24 no.3
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• pp.125-146
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• 2008

Port marketing using websites in the e-business environment is essential in response to the competition to become hub ports, especially since shipping companies, ports' major customers, are being pressed by shippers to reduce logistics costs and introduce large ships to realize economies of scale, thereby reducing the number of ports of call. In this sense, this study intends to approach the port industry from the perspective of e-business and suggest vitalization methods using Gwangyang Port websites(6C; contents, community, communication, connection, commerce, customization) as one of the ways to turn it into Northeast Asia's hub port of logistics.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.259-265
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• 2006

As a core area of the new computing paradigm, the Ubiquitous Sensor Network Technology utilizes a wireless sensor networking which can be applied to the Context Information Monitoring System. When the technology is used in a poor user-environment for monitoring purposes, it can cost-effectively gather the context data on real-time basis, analyze the information gathered, effectively response to the user situation, and execute orders to create environmental factors desired by the user. This study structures a system able to monitor information in regards to a user-environment based on wireless-node sensor technology coupled with the Ubiquitous Sensor Network Technology. The proposed system requires a minimal collection of data without continuous monitoring. Monitoring periodically, it can sense the user-environment more efficiently than the existing monitoring technologies based on the wire-communication technology.