• Journal of the Korean Wood Science and Technology
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• 제23권1호
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• pp.49-53
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• 1995

The terpenoids are one of the secondary metabolities in Pinus species and functioned the protection them from insects or/and fungus etc. Since Pinus koraiensis has not any damage by Pine needle gall midge but Pinus densiflora has great injury by them in South Korea. It may great helf to find these reasons to analize their monoterpenenoids and to compare the seasonal variation of their amounts. Terpenoids were analized by GC, GC/MS. Some biogenetic analysis of terpenoids also was elucidated. The seasonal variation of terpenoid was distinguished at March and August and/or September. Most of major component of monoterpenes were increased or decreased in these periods in Pinus koraiensis. Especially 3-carene was showed significant variation between the period of physiological activity and the period of domain. The effect of infection by Pine needle gall midge was significant in Pinus densiflora for amount of monoterpene during the period of infection. The components of p-menthane series between Pinus densiflora and Pinus koraiensis was recognized a significant difference during the experiment. Biogenetic cooccurrance of pmenthane series also was recognized between 3-carene and terpinolene in Pinus koraiensis.

• Journal of Ocean Engineering and Technology
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• 제23권1호
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• pp.1-6
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• 2009

The paper describes results of a sensitivity study on an optimum mooring cost as a function of safety factor and allowable maximum offset of the offshore floating structure by finding the anchor leg component size and the declination angle. A harmony search (HS) based mooring optimization program was developed to conduct the study. This mooring optimization model was integrated with a frequency-domain global motion analysis program to assess both cost and design constraints of the mooring system. To find a trend of anchor leg system cost for the proposed sensitivity study, optimum costs after a certain number of improvisation were found and compared. For a case study a turret-moored FPSO with 3 ${\times}$ 3 anchor leg system was considered. To better guide search for the optimum cost, three different penalty functions were applied. The results show that the presented HS-based cost-optimum offshore mooring design tool can be used to find optimum mooring design values such as declination angle and horizontal end point separation as well as a cost-optimum mooring system in case either the allowable maximum offset or factor of safety varies.

• Proceedings of the Korea Contents Association Conference
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.275-278
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• 2005

We describe the Ubiquitous Healthcare Service(UHS) architecture, a new service-provision architecture, covering the basic concept, component and their roles and the service-provision mechanism. A UHS provides services in two phases, a service composition phase in which Healthcare Service Elements (HSEs) are combined on the basis of Healthcare Service Agents (HSAs), and a Healthcare Service emergence phase in which a new HSA is obtained on the basis of the history usage of HSEs and HSAs. A UHS can handle various types of HSEs, representing web services, resources about healthcare domain. The establishment of UHS technologies on networks will provide various services within ubiquitous-computing environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제9권3호
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• pp.561-569
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• 2005

Recently, the object-oriented design is the major paradigm for software development. Most systems are following this paradigm, but the past studies for a video conversation domain were not based on full-scale object-oriented design. Thus, this paper presents an systematical architecture design using UML for a video conversation system that is well-known and has high rate of usefulness. It analysis a video conversation system that has much demand of service as systematical functional/non-functional requirements, and the object-oriented design applying '4+1 View Model' guarantees the reusability of a component and makes it possible to extend a system by adding components as needed. Consequently, it is expected that the components of video conversation system designed by this paper will be useful the other video conversation systems and will be expanded to web environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권4호
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• pp.758-763
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• 2006

In various fields of basic science and engineering, in order to present signals and systems exactly and acquire useful information from spatial and timely changes, many researches have been processed. In these methods, the Fourier transform which represents signal as the combination of the frequency component has been applied to the most fields. But as transform not to consider time information, the Fourier transform has its limitations of application. To overcome this problem, a variety of methods including the wavelet transform have been proposed. As transform to represent signal by using the changing window, according to scale parameter in time-scale domain, the wavelet transform is capable of multiresolution analysis and defines various functions according to the application environments. In this paper, to detect features of signal we analyzed wavelet the spectrum by using the basis function of the fourier transform.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제16권7호
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• pp.1391-1396
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• 2012

It is introduced an approach to model for numerical analysis of a sound absorbing material that has different absorbing coefficient according to frequency. For modeling of a sound absorbing material, we tried to model by a traditional modeling method. But it had large differences on frequency domain, especially a capacitance component due to increasing of frequency. We approach to model a sound absorbing material by the Debye polarization technique with non-linear least square method. At first, we estimated parameters form a polyurethane with thickness 25 mm, then we could model a polyurethane with thickness 50 mm using same parameters. Therefor, we could find that the Debye polarization is an useful way to model sound absorbing materials.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.151.2-151.2
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• 2014

Broadband impedances for the 3-GeV pohang light source-II (PLS-II) storage ring have been numerically estimated using a full three dimensional finite-difference time-domain code, CST particle studio. The total broadband impedance of all the vacuum components was estimated as 0.256 ohm, which is a small fraction of the total machine impedance budget.

• Journal of Power Electronics
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• 제16권5호
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• pp.1851-1860
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• 2016

The traction motors in electric multiple unit (EMU) trains are powered by AC-DC-AC converters, and the DC link voltage is generated by single phase PWM converters, with a fluctuation component under twice the frequency of the input catenary AC grid, which causes fluctuations in the motor torque and current. Traditionally, heavy and low-efficiency hardware LC resonant filters parallel in the DC side are adopted to reduce the ripple effect. In this paper, an analytical model of the ripple phenomenon is derived and analyzed in the frequency domain, and a ripple control scheme compensating the slip frequency of rotor vector control systems without a hardware filter is applied to reduce the torque and current ripple amplitude. Then a relatively simple discretization method is chosen to discretize the algorithm with a high discrete accuracy. Simulation and experimental results validate the proposed ripple control strategy.

• Journal of Power Electronics
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• 제18권3호
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• pp.802-816
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• 2018

A digital direct phase-shift control (DDPSC) method based on the phase-shifted full-bridge LLC (PSFB-LLC) converter is presented. This work combines DDPSC with the conventional linear control to obtain a hybrid control strategy that has the advantages of linear control and DDPSC control. The strategy is easy to realize and has good dynamic responses. The PSFB-LLC circuit structure is simple and works in the fixed frequency mode, which is beneficial to magnetic component design; it can realize the ZVS of the switch and the ZCS of the rectifier diode in a wide load range. In this work, the PSFB-LLC converter resonator is analyzed in detail, and the concrete realization scheme of the hybrid control strategy is provided by analyzing the state-plane trajectory and the time-domain model. Finally, a 3 kW prototype is developed, and the feasibility and effectiveness of the DDPSC controller and the hybrid strategy are verified by experimental results.

• Journal of Information Processing Systems
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• 제12권4호
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• pp.765-778
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• 2016

In watermarking schemes, the discrete wavelet transform (DWT) is broadly used because its frequency component separation is very useful. Moreover, LU decomposition has little influence on the visual quality of the watermark. Hence, in this paper, a novel blind watermark algorithm is presented based on LU transform and DWT for the copyright protection of digital images. In this algorithm, the color host image is first performed with DWT. Then, the horizontal and vertical diagonal high frequency components are extracted from the wavelet domain, and the sub-images are divided into $4{\times}4$ non-overlapping image blocks. Next, each sub-block is performed with LU decomposition. Finally, the color image watermark is transformed by Arnold permutation, and then it is inserted into the upper triangular matrix. The experimental results imply that this algorithm has good features of invisibility and it is robust against different attacks to a certain degree, such as contrast adjustment, JPEG compression, salt and pepper noise, cropping, and Gaussian noise.