• Neurospine
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• v.15 no.4
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• pp.306-322
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• 2018

This review introduces the current technique of photoacoustic imaging as it is applied in imaging-guided surgery (IGS), which provides the surgeon with image visualization and analysis capabilities during surgery. Numerous imaging techniques have been developed to help surgeons perform complex operations more safely and quickly. Although surgeons typically use these kinds of images to visualize targets hidden by bone and other tissues, it is nonetheless more difficult to perform surgery with static reference images (e.g., computed tomography scans and magnetic resonance images) of internal structures. Photoacoustic imaging could enable real-time visualization of regions of interest during surgery. Several researchers have shown that photoacoustic imaging has potential for the noninvasive diagnosis of various types of tissues, including bone. Previous studies of the surgical application of photoacoustic imaging have focused on cancer surgery, but photoacoustic imaging has also recently attracted interest for spinal surgery, because it could be useful for avoiding pedicle breaches and for choosing an appropriate starting point before drilling or pedicle probe insertion. This review describes the current instruments and clinical applications of photoacoustic imaging. Its primary objective is to provide a comprehensive overview of photoacoustic IGS in spinal surgery.

• Publications of The Korean Astronomical Society
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• v.33 no.3
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• pp.45-57
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• 2018

Low-mass star-formation studies deal with the birth of individual solar-type stars as it occurs in nearby molecular clouds. While this isolated mode of star formation may not represent the most common form of stellar birth, its study often provides first evidence for the general ingredients of star formation, such as gravitational infall, disk formation, or outflow acceleration. Here I briefly review the current status and the main challenges in our understanding of low-mass star formation, with emphasis in the still mysterious pre-stellar phase. In addition to presenting by-now classical work, I also show how ALMA is starting to play a decisive role driving progress in this field.

• Journal of Marine Life Science
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• v.1 no.1
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• pp.70-78
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• 2016

Microalgae are of significant importance for future biotechnological applications. Many microalgae banks or laboratories attempt to maintain various microalgae for further research purposes. Cryopreservation has been preferred to reduce a labor-intensive and costly routine sub-culturing. Cryopreservation can also diminish the genetic drift risk. However, cryopreservation as a long term storage of microalgae method are still in developing progress because it cannot be generalized for all microalgae. Microalgae types, cryoprotectant agents (CPAs) types, freezing and thawing methods are the most important factors that should be considered for cryopreservation. In this short review the basic principles and the current advanced of microalgae cryopreservation methods are discussed with a suggested starting parameters for microalgae cryopreservation.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.188-191
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• 2002

To reduce the bit-rate of video sequences by removing temporal redundancy, motion estimation techniques have been developed. However, the high computational complexity of the problem makes such techniques very difficult to be applied to high-resolution applications in a real time environment. For this reason, low computational complexity motion estimation algorithms are viable solutions. If a priori knowledge about the motion of the current block is available before the motion estimation, a better starting point for the search of n optimal motion vector on be selected and also the computational complexity will be reduced. In this paper, we present an adaptive block matching algorithm based on temporal correlations of consecutive image frames that defines the search pattern and the location of initial starting point adaptively to reduce computational complexity. Experiments show that, comparing with DS(Diamond Search) algorithm, the proposed algorithm is about 0.1∼0.5(㏈) better than DS in terms of PSNR and improves as much as 50% in terms of the average number of search points per motion estimation.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.486-493
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• 2017

Refineries and chemical plants with isolated power systems that have a limited power supply are more susceptible to voltage changes from disturbances compared to power systems connected with a power company. Furthermore, most loads in such cases are induction motor loads, and therefore, transient voltage characteristics when starting a high-capacity motor must be examined. In general, high-capacity motors are customized appropriately to the load performance curve by the manufacturer during the construction of an industrial plant. Subsequently, when complying with the voltage drop permitted by international standards during the design process, power supply equipment such as transformers and generators is overdesigned. Therefore, a novel analysis is necessary on standards for startup and constraint voltage drops, as well as on identifying the voltage drop limitations for starting high-capacity motors in refineries and chemical plants with isolated power systems. In this study, field tests on an industrial plant were conducted, and simulations modeled under conditions identical to those of the field test system were performed using the general-purpose program ETAP in order to compare the results.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.34-38
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• 2005

The finite element method is very flexible for new shapes and provides flux distribution, magnetomotive force, eddy currents, and torques. However, it requires lengthy computational time in order to achieve desired accuracy. The magnetic equivalent circuit method takes less computation time than the finite element method. Therefore, the finite element method is mainly used to confirm the completed design. The magnetic equivalent circuit method is convenient for complicated analysis of the transient state of the induction motor. The magnetic equivalent circuit method is restricted to only one direction of magnetic flux. In this paper, the construction elements (that is, stator iron, rotor iron, yoke, air gap, etc.) of the squirrel cage induction motor were represented by a flux tube and the air gap magnetomotive force was calculated by the magnetic equivalent circuit method. Starting transient torque and phase current of the squirrel cage induction motor were verified by the theoretical calculation and the experiment.

• The Journal of Korean Medicine
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• v.17 no.2 s.32
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• pp.48-57
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• 1996

This study is to review the oriental medical literatures about Chungye and endocrinologic literatures about menstration, pregnancy, menopause and male-sex cycle. The conclusions obtained are as follows; First, according to Naegyung, Chungye exists in both male and female, it makes human fertile. It comes with starting menstration and is exhausted with menopause. Second, it was said that the name of Chungye originated in Chun of Chunjinjiki(energy of genuine cosmos) and Gye of Imgyejisu(water of Imgye). Third, some authors advocated that Chungye is menstration. But it was criticized by other authors and it is not accepted at the present time. Forth, there was an assertion that Chungye is Eumjung. The assertion has been developed as the hypothesis that Chungye may be a endocrinologic substance relavant to menstration and pregnancy. Fifth, there was an interpretation that Chungye is FSH. But this interpretation might be unreasonable if it is based on the results observed by endocrinologic researches. According to the current endocrinologic researches, Chungye may be GnRH, when Chungye is the necessary endocrinologic substance to menstration and pregnancy, exists in male and female and is exhausted with menopause.

• Health Policy and Management
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• v.28 no.3
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• pp.197-201
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• 2018

There is a general consensus that many health care problems are attributable to the structural defects of the health care delivery system in Korea. The basic policy aimed to address these problems is to reform the delivery system so as that it incorporates two core principles: (1) stratification of medical care institutions into primary, secondary, and tertiary care providers according to the capability to perform specialized and complex services; (2) patients seeking care starting from the primary care provider and, if necessary, to be referred to the other provider step by step. This policy has been consistently pursued for about 30 years, but the achievement is far from success. Thus it is believed that the feasibility of the policy should be questioned. Starting from this question, based upon the observation of the current structure of the delivery system and its expected changes, the reform policy was discussed focusing on the assessment of its feasibility from both practical and theoretical viewpoints. The discussion leads to cast doubt on the policy for its possibility of making planned changes and producing expected desirable effects. Therefore it is advisable to investigate a wide range of alternative strategies and models for improving health care delivery.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.208-210
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• 1994

In this paper, the design sensitivity evaluation based on the 2-dimensional finite clement discretization is presented for the voltage source and eddy current problem. And it is applied to the two shape design problems of the rotor slot of 3-phase squirrel cage induction motors. The first is to increase the starting torque while keeping the rated torque fixed. The other is only to increase the torque at the rated speed while keeping the starting torque fixed. As an optimization method, the Gradient Projection method is used to control casily the torques for various speeds of rotor. One fourth of rotor is analyzed by using a semi-periodic boundary condition. Because the shape of rotor slot has much influence on the slip torque characteristic, the 10 design parameters are taken on the interface between rotor core and rotor bar. The initial shape of rotor slot is the trapezoidal typo with rounding corners.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1260-1263
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• 2000

Vector control of a single phase induction machine(SPIM) is usually employed by mechanical methods than electrical ones. The disadvantage of a SPIM has large noise at the starting. Using auxiliary winding which is only utilized for starting, the SPIM can be controlled with the vector control method. Regarding a auxiliary winding one phase, the SPIM is analyzed by the unsymmetrical two phase motor and phase transformation is unnecessary such as three phase IM. Including a auxiliary winding, SPIM is modeled by mathematical getting by component of turns ratio with main to auxiliary winding. It will be take with complicated resultant formula, by comparison to symmetrical three phase TM. For using the vector control theory, it must be decoupled of rotor flux and torque component. stator current is controlled and decoupled. This paper presents a variable-speed control system of SPIM, which to decoupled with flux and torque component and to use machine equivalent circuit referred to rotor, conventionally three phase IM by similar method.