• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.89-99
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• 2008

In this paper proposes a novel tacking algorithm regarding the power loss when operating a tracking system for a rapidly changing insolation to improve the power of PV hacking system. The tracking system of sensor method used in a conventional PV power station is unable to exactly track a sun position when lacking in the intensity of radiation and has the problem is malfunction of tracking system by a rapidly changing climatic. The tracking system of program method spends too much energy on the unnecessary operation of tracking system because that is unable to adapt itself to a outside factor of climatic environment. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this pap proposes a novel control algorithm of the tracking system. Also, this paper is analyzed efficiency of traditional solar tracking method and proposed method, prove validity of proposed algorithm through demonstrable study.

• Journal of Chest Surgery
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• v.27 no.2
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• pp.140-147
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• 1994

Reconstruction of the pharynx and cervical esophagus presents a tremendous challenges to surgeons. Over the past 2 years[1990, Dec.-1993, Jun], the free jejunal graft has been performed in 17 cases in Korea Cancer Center Hospital.The indications of this procedures were almost malignant neoplasms involving neck and upper aero-digestive tract; Hypopharyngeal cancer[12 cases, including 2 recurrent cases], laryngeal cancer[2 cases], thyroid cancer[2 cases, including 1 recurrent case], cervical esophageal cancer[1 case]. There were fifteen men and two women, and the mean age was 59.6 years. The anastomosis site of jejunal artery were common carotid artery[16 cases] or external carotid artery[1 case] and that of jejunal vein were internal jegular [15 cases] or facial[1 case] and superior thyroid vein[1 case]. The length of jejunal graft was from 9 cm to 17 cm[mean 13 cm] and the mean ischemic time was 68 minutes. There was one hospital mortality which was irrelevant to procedures[variceal bleeding] and one graft failure[1/16]. Other postoperative complications were neck bleeding or hematoma[3 cases], abdominal wound infection or disruption[5 cases], anastomosis site leakage[1 case], pneumonia[2 cases], graft vein thrombosis[1 case], and food aspiration[1 case]. The function of conduit was excellent and ingestion of food was possible in nearly all cases. Postoperative adjuvant radiation therapy was also applicable without problem in 7 cases. During follow-up periods, the anastomosis site stenosis developed in four patients, and the tracheal stoma was narrowed in one case but easily overcome with dilation. In conclusion, we think that the free jejunal graft is one of the excellent reconstruction methods of upper digestive tract, especially after radical resection of malignant neoplasm in neck with a high success rate and low mortality and morbidity rate.

• Journal of Advanced Navigation Technology
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• v.24 no.4
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• pp.291-298
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• 2020

This study proposed a model that can track MPP faster than the existing MPPT algorithm using the particle swarm optimization algorithm (PSO). The proposed model highly sets the acceleration constants of gbest and pbest in the PSO algorithm to quickly track the MPP point and eliminates the power instability problem. In addition, this algorithm was re-executed by detecting the change in power of the solar panel according to the rapid change in solar radiation. As a result of the experiment, MPP time was 0.03 seconds and power was 131.65 for 691.5 W/m2, and MPP was tracked at higher power and speed than the existing P&O and INC algorithms. The proposed model can be applied when a change in the amount of power is detected by partial shading in a Photovoltaic power plant with Photovoltaic connected in parallel. In order to improve the MPPT algorithm, this study needs a comparative study on optimization algorithms such as moth flame optimization (MFO) and whale optimization algorithm (WOA).

• Journal of Korean Neurosurgical Society
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• v.39 no.6
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• pp.409-412
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• 2006

Objective : Primary central nervous system lymphoma[PCNSL] is a non-Hodgkin's lymphoma arising in the central nervous system. Combined chemotherapy and radiation therapy is the standard treatment for PCNSL. However, treatment induced neurotoxicity is a major problem especially in elderly patients. Methods : From May 2001 to April 2004, elderly five patients with PCNSL confirmed via pathological examination were underwent Novalis radiosurgery in authors' institution, who were investigated retrospectively. Of these patients, 2 were male and 3 were female, with a mean age 68 years old [range $65{\sim}73$]. The number of lesions was 1 in 2 patients, 2 in 2, and 3 in 1. The mean follow up period was 12.6 months [range $8{\sim}16$]. Results : Clinical symptoms and signs in all patients markedly improved within 1 weeks after Novalis radiosurgery. The Karnofsky performance status score was also improved from a pre-radiosurgery average of 68 to a post-radiosurgery one of 82. All of treated lesions showed a partial or complete regression of the original mass. There have been no complication following Novalis radiosurgery. Conclusion : The preliminary results of our experience indicate that radiosurgery with Novalis provides a safe and effective therapeutic alternative treatment of PCNSL in elderly patients.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.984-989
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• 2008

In this paper, we will design a 800MHz broadband antenna after a problem of the narrow bandwidth is improved. This multiple band antenna unifies the CDMA(Code Division Multiple Access), GSM(Global System for Mobile Telecommunication) and TRS(Trunked Radio System) band in the UHF band, and then it is possible at the shore base station or repeater as the commercial use. It used the duplex resonance effect it had the L-shared feeding structure which adds the U-slot. And it improved profit using stack structure. It was measured that the frequency bandwidth of the designed antenna which is planed $792{\sim}1040MHz$ with 248MHz(33%). And the antenna gain is 9.4dBi, 3dB beam width $60^{\circ}$ in radiation pattern.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.460-465
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• 2019

In this study, we aim to derive a solution from the structural analysis for electrical failure of single board computers for computing navigation information. By analyzing the characteristic factor, we identify that crack occur on the central processing unit board due to a certain structural problem, and that the physical effect by the crack make communication function be impossible to perform, which it causes booting error. In order to find the location of excessive stress causing the crack, structural analysis for the single board computer is done. From the structural analysis, the areas where stress concentration occurs are identified, and improvement methods changing the structures are developed. As a result, we shows that stresses are reduced entirely on the stress distribution for the improved structure. In addition, heat analysis shows that changing the structure to reduce stresses is not affect to the heat radiation, and the thermal resistance of the actual equipment is verified by measuring the temperature of the heat sink applied with the improved structure.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.187-193
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• 2008

Interface technologies for a user to control home automation system in wearable computing environment has been studied recently. This paper proposes a new interface method for a disabled person to control home automation system in wearable computing environment by using EOG sensing circuit and marker recognition. In the proposed interface method, the operations of a home network device are represented with human readable markers and displayed around the device. A user wearing a HMD, a video camera, and a computer selects the desired operation by seeing the markers and selecting one of them with eye movement from the HMD display The requested operation is executed by sending the control command for the selected marker to the home network control device. By using the EOG sensing circuit and the marker recognition system a user having problem with moving hands and fit can manipulate a home automation system with only eye movement.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.11-22
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• 2019

In this paper, a Rankine source method is applied and validated to analyze the hydrodynamic response of a three-dimensional floating structure in the frequency domain. The boundary value problems for radiation and diffraction problem are solved by using a desingularized indirect boundary integral equation method (DIBIEM). The DIBIEM is simpler and faster than conventional methods based on the numerical surface integration of Green's function because the singularities of Green's function are located outside of fluid regions. In case of floating structure with complex geometry, it is difficult to desingularize the singularities of Green's function consistently. Therefore a mixed approach is carried out in this study. The mixed approach is partially desingularized except singularities of the body. Wave drift loads are calculated by the middle-field formulation method that is mathematically simple and has fast convergence. In order to validate the accuracy of the developed program, various numerical simulations are carried out and these results are analyzed and compared with previously published calculations and experiments.

• Korean Journal of Heritage: History & Science
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• v.48 no.3
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• pp.138-153
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• 2015

For preventing the biological damage domestically, insect damage control method using chemical medicine has been applied. However, it is trend to avoid existing chemical medicine such as Methyl bromide because of the problem of being harmful to human body and environment. Therefore, the research for new medicine to replace this has been done and the interest to the physical treatment such as temperature(high & low) treatment, hypoxic treatment, carbon dioxide treatment, and radiation treatment has increased. However the systematic application standard and way has not been established. Therefore, in this research, we are going to organize present condition of domestic cultural asset preventing biological damage after the 1980's. It will also consider the direction through the characteristic of technology, limit, and replacement medicine by examining the past research.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.4
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• pp.171-178
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• 2019

The use of anti-scatter grids in radiographic imaging has the advantage of preventing the image distortion caused by scattered radiation. However, it carries the side effect of leaving artifacts in the X-ray image. In this paper, we propose a grid line suppression technique using discrete cosine transform(DCT). In X-ray images, the grid lines have different characteristics depending on the shape of the object and the area of the image. To solve this problem, we adopt the DCT transform based on a dynamic segmentation, and propose a filter transfer function for each individual segment. An algorithm for detecting the band of grid lines in frequency domain and a band stop filter(BSF) with a filter transfer function of a combination of Kaiser window and Butterworth filter have been proposed. To solve the blocking effects, we present a method to determine the pixel values using multiple structured images. The validity of the proposed theory has been evaluated from the experimental results using 140 X-ray images.