• Journal of Korean Neurosurgical Society
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• v.45 no.2
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• pp.99-102
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• 2009

Inflammatory pseudotumor is an uncommon lesion with unknown etiology characterized by sclerosing inflammation which clinically and radiographically mimics a neoplastic lesion. A 47-year-old man presented with sudden headache and dysarthria. Brain CT scan revealed a $2.6{\times}2.2\;cm$ sized, round, and hyperdense mass in the anterolateral wall of the left lateral ventricular trigone. On MR imaging studies, the mass showed low signal intensity in the wall of the trigone on T2-weighted image, central mixed (iso- and high-) signal intensity with peripheral low-signal intensity on T1-weighted image. Subtle staining of left choroid plexus with irregular shaped distal branch of anterior choroidal artery was found on the cerebral angiography. These findings suggested a small tumorous lesion originated from the left choroid plexus. During the hospital days, the mass manifested as repeated hemorrhages. The mass was successfully removed via left occipital transcortical approach. The histopathological report of the specimen was hemorrhage and fibrosis, with dense lymphoplasma cell infiltration, suggestive of an inflammatory pseudotumor.

• Journal of Information Processing Systems
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• v.5 no.2
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• pp.69-76
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• 2009

Self healing systems are considered as cognation-enabled sub form of fault tolerance system. But our experiments that we report in this paper show that self healing systems can be used for performance optimization, configuration management, access control management and bunch of other functions. The exponential complexity that results from interaction between autonomic systems and users (software and human users) has hindered the deployment and user of intelligent systems for a while now. We show that if that exceptional complexity is converted into self-growing knowledge (policies in our case), can make up for initial development cost of building an intelligent system. In this paper, we report the application of AHSEN (Autonomic Healing-based Self management Engine) to in OKKAM Project infrastructure backbone cluster that mimics the web service based architecture of u-Zone gateway infrastructure. The 'blind' load division on per-request bases is not optimal for distributed and performance hungry infrastructure such as OKKAM. The approach adopted assesses the active threads on the virtual machine and does resource estimates for active processes. The availability of a certain server is represented through worker modules at load server. Our simulation results on the OKKAM infrastructure show that the self healing significantly improves the performance and clearly demarcates the logical ambiguities in contemporary designs of self healing infrastructures proposed for large scale computing infrastructures.

• Publications of The Korean Astronomical Society
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• v.15 no.spc1
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• pp.147-151
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• 2000

Symbiotic stars, believed to be binary systems of a mass-losing giant and a white dwarf with an emission nebula, are known to exhibit very broad wings around Hex that extend to $\~10^3km\;s^{-1}$. The wing formation mechanism is not a settled matter and recently Lee (2000) proposed that Raman scattering of Ly$\beta$ by neutral hydrogen is responsible for the broad H$\alpha$ wings. In this model, it is predicted that. the Hex wings will be polarized depending on the geometric and kinematic distribution of the scatterers relative to the UV emission region. In this paper, we investigate the polarization of Hex wings in symbiotic stars. Noting that many symbiotic stars possess bipolar nebular morphology, we assume that the distribution of neutral scatterers follows the similar pattern with a receding velocity of several tens of km $s^{-1}$ that mimics the expansion of the neutral envelope of the nebula. It is found that the red wing is more strongly polarized than the blue and main part and that the polarization direction is along the equatorial plane. We obtain a typical degree of polarization $\~10$ percent, however, it varies depending on the detailed distribution of H I scatterers We conclude that spectropolarimetry will provide very important information on the origin of the Hex wings.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.436-438
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• 2002

As the use of virtual simulation expands, digitally reconstructed radiographs (DRRs), which mimic conventional simulation films, play an increasingly important role as reference images in the verification of treatment fields. The purpose of our study is to develop an algorithm for computation of digitally reconstructed radiographs based on Monte Carlo simulation that take into account almost all possible physical processes by which photons interact with matter. The Monte Carlo simulation based DRRs have the following features. 1) Account has been taken of almost all possible physical processes of interaction of photons with matter, including a detector (film) response. In principle, this is equivalent to X-ray radiography. 2) Arbitrary photon energies (from diagnostic to therapeutic) can be used to produce DRRs. One can even use electrons as the source. 3) It is easy to produce a double exposure, which mimics the double exposure portal image and may have superior visual appeal for treatment field verification, with weighting within the treatment field.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1142-1166
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• 2020

Salp Swarm Algorithm (SSA) is a new nature-inspired swarm optimization algorithm that mimics the swarming behavior of salps navigating and foraging in the oceans. SSA has been proved to enable to avoid local optima and enhance convergence speed benefiting from the adaptive nonlinear mechanism and salp chains. In this paper, visual tracking is considered to be a process of locating the optimal position through the interaction between leaders and followers in successive images. A novel SSA-based tracking framework is proposed and the analysis and adjustment of parameters are discussed experimentally. Besides, the qualitative analysis and quantitative analysis are performed to demonstrate the tracking effect of our proposed approach by comparing with ten classical tracking algorithms. Extensive comparative experimental results show that our algorithm has good performance in visual tracking, especially for abrupt motion tracking.

• Clinics in Shoulder and Elbow
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• v.21 no.3
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• pp.134-137
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• 2018

Background: In a previous study undertaken to quantify capsular volume in rotator cuff interval or axillary pouch, significant differences were found between controls and patients with instability. However, the results obtained were derived from two-dimensional cross sectional areas. In our study, we sought correlation between three-dimensional (3D) capsular volumes, as measured by magnetic resonance arthrography (MRA), and multidirectional instability (MDI) of the shoulder. Methods: The MRAs of 21 patients with MDI of the shoulder and 16 control cases with no instability were retrospectively reviewed. Capsular areas determined by MRA were translated into 3D volumes using 3D software Mimics ver. 16 (Materilise, Leuven, Belgium), and glenoid surface area was measured in axial and coronal MRA views. Then, the ratio between capsular volume and glenoid surface area was calculated, and evaluated with control group. Results: The ratio between 3D capsular volume and glenoid surface area was significantly increased in the MDI group ($3.59{\pm}0.83cm^3/cm^2$) compared to the control group ($2.53{\pm}0.62cm^3/cm^2$) (p<0.01). Conclusions: From these results, we could support that capsular volume enlargement play an important role in MDI of the shoulder using volume measurement.

• Tuberculosis and Respiratory Diseases
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• v.52 no.5
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• pp.550-556
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• 2002

Microscopic polyangiitis is a systemic small-vessel vasculitis that is associated primarily with necrotizing glomerulonephritis and pulmonary capillaritis. A recurrent and diffuse alveolar hemorrhage due to pulmonary capillaritis is the main clinical manifestation of lung involvement. Recently, and interstitial lung disease that mimics idiopathic pulmonary fibrosis was reported to be rarely associated with microscopic polyangiitis. Here we report two patients with microscopic polyangiitis who showed a honeycomb lung at the time of the initial diagnosis with a brief review of relevant literature.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.65-71
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• 2009

In this paper, we propose an aircraft on-glass antenna for FM radio reception. To obtain broad matching bandwidth, we employed a multiple loop as the basic antenna structure, and the shape of the loops mimics the frame of a window in order to ensure pilots' field of view as large as possible. The detailed design parameters of the multi-loop structure were determined using a Pareto genetic algorithm with a full wave EM simulation tool. The optimized on-glass antenna was built and installed on a Korean utility helicopter (KUH) The measurement results showed a half power matching bandwidth of about 63.3 %, average vertical bore-sight gain of about -12.98 dBi in the FM band.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.133-140
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• 2017

The performance prediction software developed in this paper is a process analysis tool that enables one to foretell the behavior of processes when certain conditions of operation are altered. The immediate objective of this research is to predict the process characteristics of combined heat and power plant under varying operating conditions. A cogeneration virtual power plant that mimics the mechanical performance of the actual plant was constructed and the performance of the power plant was predicted in the following varying atmospheric conditions: temperature, pressure and humidity. This resulted in a positive outcome where the performance of the power plant under changing conditions were correctly predicted as well as the calorific value of low calorific gas fuel such as shale gas and PNG. The performance prediction tool can detect the operation characteristics of the power plant through the performance index analysis and thus propose the operation method taking into consideration the changes in environmental conditions.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.143-148
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• 2018

In this paper, the optimal fuzzy logic controller(FLC) for a hybrid renewable energy system(HRES) is proposed. Generally, hybrid renewable energy systems can consist of wind power, solar power, fuel cells and storage devices. The proposed FLC can effectively control the entire HRES by determining the output power of the fuel cell or the absorption power of the electrolyzer. In general, fuzzy logic controllers can be optimized by classical optimization algorithms such as genetic algorithms(GA) or particle swarm optimization(PSO). However, these FLC have a disadvantage in that their performance varies greatly depending on the control parameters of the optimization algorithms. Therefore, we propose a method to optimize the fuzzy logic controller using the teaching-learning based optimization(TLBO) algorithm which does not have the control parameters of the algorithm. The TLBO algorithm is an optimization algorithm that mimics the knowledge transfer mechanism in a class. To verify the performance of the proposed algorithm, we modeled the hybrid system using Matlab Tool and compare and analyze the performance with other classical optimization algorithms. The simulation results show that the proposed method shows better performance than the other methods.