• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.219-221
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• 2007

Recent changes to ubiquitous computing requires more natural human-computer(HCI) interfaces that provide high information accessibility. Hand-gesture, i.e., gestures performed by one 'or two hands, is emerging as a viable technology to complement or replace conventional HCI technology. This paper deals with hand-posture recognition. Hand-posture database construction is important in hand-posture recognition. Human hand is composed of 27 bones and the movement of each joint is modeled by 23 degrees of freedom. Even for the same hand-posture,. grabbed images may differ depending on user's characteristic and relative position between the hand and cameras. To solve the difficulty in defining hand-postures and construct database effective in size, we present a method using a 3D hand model. Hand joint angles for each hand-posture and corresponding silhouette images from many viewpoints by projecting the model into image planes are used to construct the ?database. The proposed method does not require additional equations to define movement constraints of each joint. Also using the method, it is easy to get images of one hand-posture from many vi.ewpoints and distances. Hence it is possible to construct database more precisely and concretely. The validity of the method is evaluated by applying it to the hand-posture recognition system.

• Korean Journal of Remote Sensing
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• v.31 no.4
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• pp.337-346
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• 2015

Water body extraction based on backscatter information is an essential process to analyze floodaffected areas from Synthetic Aperture Radar (SAR) image. Water body in SAR image tends to have low backscatter values due to homogeneous surface of water, while non-water body has higher backscatter values than water body. Non-water body, however, may also have low backscatter values in high resolution SAR image such as Kompsat-5 image, depending on surface characteristic of the ground. The objective of this paper is to present a method to increase backscatter contrast between water body and non-water body and also to remove efficiently misclassified pixels beyond true water body area. We create an entropy image using a Gray Level Co-occurrence Matrix (GLCM) and classify the entropy image into water body and non-water body pixels by thresholding of the entropy image. In order to reduce the effect of threshold value, we also propose Water Body Texture Index (WBTI), which measures simultaneously the occurrence of repeated water body pixel pair and the uniformity of water body in the binary entropy image. The proposed method produced high overall accuracy of 99.00% and Kappa coefficient of 90.38% in water body extraction using Kompsat-5 image. The accuracy analysis indicates that the proposed WBTI method is less affected by the choice of threshold value and successfully maintains high overall accuracy and Kappa coefficient in wide threshold range.

• Korean Journal of Veterinary Research
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• v.29 no.1
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• pp.75-79
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• 1989

The etiologic agents of mucormycosis are several nonpathogenic fungi of the order Mucorales and are ubiquitous. A total of 82 chickens were infected with the disease and developed anorexia, diarrhea, malnutrition, dyspnea, and paralysis in a chicken farm, Sokcho, Kwangwon. At necropsy there were multiple nodular lesions and hemorrhages in livers, spleens, kidneys, gastrointestinal track, and respiratory system. On histopathological examination it was found that the nodular lesions were consisted of granoulomatous inflammation accompanying characteristic hyphae ($4{\sim}24{\mu}$ wide) of the fungi.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.112-112
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• 2001

Oxidative stress plays an important role in the pathological process of neurodegenerative diseases. Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants, some of which may be neurotoxic. Our previous studies showed that 2,2',5,5'-TetracWorobiphenyl (PCB 52) induced apoptotic death in human neuronal SK-N-MC cells, which was demonstrated on gel electrophoresis by visualization of the proteolytic cleavages of $\beta$-catenin and poly (ADP-ribose) polymerase (PARP) and of the production of characteristic ladder patterns of DNA fragmentation.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.1-13
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• 2008

Recently, interest about Mobile Office Environment is increasing Messenger system of 'Ubiquitous Mobile Office Environment' need various kinds new concept such os request/broadcasting/transmission of working environment that existent messenger protocol does not support. Design correct new protocol to Mobile Office Environment messenger in this treatise, and analyzed existentprotocol and comparison. Also, examine characteristic of rendezvous server that was optimized in MOE-MP protocol and analyzed efficiency. MOE-MP that design newly based on basic syntax of XMPP optimized to Mobile Office Environment.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.225-232
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• 2004

Shocks are ubiquitous in astrophysical environments and cosmic-rays (CRs) are known to be accelerated at collisionless shocks via diffusive shock acceleration. It is believed that the CR pressure is important in the evolution of the interstellar medium of our galaxy and most of galactic CRs with energies up to ${\~}\;10^{15}$ eV are accelerated by supernova remnant shocks. In this contribution we have studied the CR acceleration at shocks through numerical simulation of 1D, quasi-parallel shocks for a wide range of shock Mach numbers and shock speeds. We show that CR modified shocks evolve to time-asymptotic states by the time injected particles are accelerated to moderately relativistic energies, and that two shocks with the same Mach number, but with different shock speeds, evolve qualitatively similarly when the results are presented in terms of a characteristic diffusion length and diffusion time. We find that $10^{-4} - 10^{-3}$ of the particles passed through the shock are accelerated to form the CR population, and the injection rate is higher for shocks with higher Mach number. The time asymptotic value for the CR acceleration efficiency is controlled mainly by shock Mach number, and high Mach number shocks all evolve towards efficiencies ${\~}50\%$, regardless of the injection rate and upstream CR pressure. We conclude that the injection rates in strong quasi-parallel shocks are sufficient to lead to significant nonlinear modifications to the shock structures, implying the importance of the CR acceleration at astrophysical shocks.

• Journal of Sensor Science and Technology
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• v.20 no.2
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• pp.118-123
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• 2011

Heart related diseases mainly caused by heavy work load and increasing stress in human daily life. Therefore, researches on mobile healthcare monitoring for daily life has been carried out. Notably, wearable healthcare monitoring system which has least restriction has been tried to provide an emergency alert of abnormal heart rate. In this study, we developed chair type unconstrained BCG measurement system which able to perform continuous heart status monitoring at the office and daily life in the unconstrained way. Furthermore, adaptive threshold is used to detect the heart rate from BCG signals. The HRV(heart rate variability) is calculated from heart rate interval. ECG signal measured using conventional method and BCG signal measured using unconstraint system are carried out simultaneously for the purpose of performance evaluation. From the comparison result, BCG signal shows a similar heart beat characteristic as ECG signal. This proves the possibility of practical implementation of unconstraint healthcare monitoring system. In addition, medical examination like valsalva maneuver is performed to observe the changes in HRV due to stress. By performing valsalva maneuver, heart is said to be placed under an artificial physical stress condition. Under this artificial physical stress condition, the time and frequency domain of HRV parameters are evaluated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.4203-4223
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• 2021

Accelerated by the Internet of Things (IoT), the need for further technical innovations and developments within wireless communications beyond the fifth generation (B5G) networks is up-and-coming in the past few years. High altitude platform station (HAPS) communication is expected to achieve such high levels that, with high data transfer rates and low latency, millions of devices and applications can work seamlessly. The HAPS has emerged as an indispensable component of next-generations of wireless networks, which will therefore play an important role in promoting massive IoT interconnectivity with 6G. The performance of communication and key technology mainly depend on the characteristic of channel, thus we propose an efficient Markov chain based channel model, then analyze the HAPS communication system's uplink capability and swing effect through experiments. According to the simulation results, the efficacy of the proposed scheme is proven to meet the requirements of ubiquitous connectivity in future IoT enabled by 6G.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4234-4243
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• 2012

USN(Ubiquitous Sensor Network) application S/W has a complex characteristic that it controls various kind of sensor nodes organically based on the core modules of various target operating systems. Currently, various researches for efficient S/W development are being performed in USN application field. In order to increase S/W productivity, the method such as product line development approach to specify core common functions of applications according to the domain and develop applications with the core common functions and variant functions selected according to the workflow of applications is efficient. To apply this approach to the USN domain, characteristics of USN application S/W and product line development should be specified with one consistent view. However, it is difficult to efficiently specify the characteristics using general UML notations. In order to solve the problem, this paper proposes a method to effectively specify the characteristics of USN applications and product line development using UML profile which is the extension mechanism of UML. The proposed UML profile for produce line based USN application development enables developers to effectively develop product line based USN applications using existing UML and UML support tools without new design methods or tools which are specified for USN or product line development.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.71-80
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• 2007

This paper presents a new push-push VCO technique that extracts a second harmonic output signal from a capacitive commonnode in a negativegm oscillator topology. The generation of the $2^{nd}$ harmonics is accounted for by the nonlinear current-voltage characteristic of the emitter-base junction diode causing; 1) significant voltage clipping and 2) different rising and falling time during the switching operation of core transistors. Comparative investigations show the technique is more power efficient in the high-frequency region that a conventional push-push technique using an emitter common node. Prototype 12GHz and 17GHz MMIC VCO were realized in GaInP/GaAs HBT technology. They have shown nominal output power of -4.3dBm and -5dBm, phase noise of -108 dBc/Hz and -110.4 dBc/Hz at 1MHz offset, respectively. The phase noise results are also equivalent to a VCO figure-of-merit of -175.8 dBc/Hz and -184.3 dBc/Hz, while dissipate 25.68mW(10.7mA/2.4V) and 13.14mW(4.38mA/3.0V), respectively.