• Analytical Science and Technology
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• v.33 no.1
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• pp.23-32
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• 2020

Methamphetamine (MA) is the most common and available drug of abuse in Korea and its primary metabolite is amphetamine (AP). Detection of AP derivatives, such as MA, AP, phentermine (PT), MDA, MDMA, and MDEA by the use of immunoassay screening is not reliable and accurate due to cross-reactivity and insufficient specificity/sensitivity. Therefore, the analytical process accepted by most urine drug-testing programs employs the two-step method with an initial screening test followed by a more specific confirmatory test if the specimen screens positive. In this study, a gas chromatography-mass spectrometric (GC-MS) method was developed and validated for confirmation of MA and AP in human urine. Urine sample (500 µL) was added with N-isopropylbenzylamine as internal standard and ethyl chloroformate as a derivatization reagent, and then extracted with 200 µL of ethyl acetate. Extracted samples were analysed with GC-MS in the SIM/ Scan mode, which were screened by Cobas c311 analyzer (Roche/Hitachi) to evaluate the efficiency as well as the compatibility of the GC-MS method. Qualitative method validation requirements for selectivity, limit of detection (LOD), precision, accuracy, and specificity/sensitivity were examined. These parameters were estimated on the basis of the most intense and characteristic ions in mass spectra of target compounds. Precision and accuracy were less than 5.2 % (RSD) and ±14.0 % (bias), respectively. The LODs were 3 ng/mL for MA and 1.5 ng/mL for AP. At the screening immunoassay had a sensitivity of 100% and a specificity of 95.1 % versus GC-MS for confirmatory testing. The applicability of the method was tested by the analysis of spiked urine and abusers' urine samples.

• Korean Journal of Acupuncture
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• v.25 no.3
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• pp.81-96
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• 2008

Objectives : The purpose of the present study is to determine the effective analgesic parameters of manual acupuncture (MA) and/or electroacupuncture (EA), thus how MA & EA of specific acupoint works after acute ankle sprain in rats. Thus, one series of experiments was designed to analyze the analgesic effects of acupuncture in either the normal or sprained rat, by comparing the behavioral features before and after MA or EA at several acupoints. Methods : Ankle sprain was induced manually by hyper-extension of ligaments of the right ankle in rat. Either MA or EA was applied to the LI4, TE17, 足三里 and SI-6 acupoints at an intensity of 2 mA (1 ms pulse duration) with a frequency of 10 Hz for 30 minutes. Results : Behaviorally, manual acupuncture or electroacupuncture produced potent analgesic effects on acute ankle sprained animals as measured by weight bearing capacity of the affected limb. Furthermore, antinociceptive effect of EA was suppressed by alpha adrenoceptor antagonist phentolamine (5 mg/kg, i.p.) but not by opioid antagonist naltrexone (10 mg/kg, i.p.). Conclusions : It is suggested that acupuncture-induced antinociception may involve the descending inhibition of ${\alpha}2$-adrenoceptor.

• Journal of Marine Life Science
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• v.9 no.1
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• pp.22-32
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• 2024

The purpose of this study was to determine the effect of external biologger attachment methods on the blood parameters and attachment efficiency of spotted sea bass Lateolabrax maculatus (mean body weight 2630.8 g). The fish were tagged using four different external attachment methods with dummy biologgers: no attachment (control), anchor attachment (AA), monofilament attachment (MA), and silicon tube attachment (SA), each with triplicates. Blood indices and biologger attachment efficiency were assessed on days 1, 7, 14, 28, 56, and 84 after attachment. The concentrations of hematocrit, Na⁺, Cl^-, glutamic pyruvic transaminase and total protein, and the activity of superoxide dismutase in blood were not affected by the external attachment method of biologger. The concentrations of glutamic oxaloacetic transaminase (day 1 of attachment), hemoglobin (day 56) and total cholesterol (day 56 and 84) in AA group, the concentrations of glucose and cortisol (day 14) and total cholesterol (day 84) in MA group showed significantly higher than those of control (p<0.05). During the experiment period, the SA group had no differences from the control in all blood properties. The biologger attachment efficiencies of the AA, MA, and SA groups after 84 days were 0.0%, 33.3%, and 100.0%, respectively. These results indicate that the optimum external biologger attachment method under our experimental conditions is SA type.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.357-359
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• 2007

In order to protect copyrighted materials, codes may be embedded in the content -to trace the traitors. Traceability (TA) codes, as a kind of such codes, have been extensively studied in the intervening years for use as a piracy deterrent. In this correspondence, we proposed a method to construct a class of traceability codes and gave out some parameters results of such codes.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.277-278
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• 2006

• Journal of the Korean Statistical Society
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• v.26 no.2
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• pp.155-170
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• 1997

We propose an integer-valued MA(q) process with Poisson disturbance. Its various properties are discussed such as the joint distribution, time reversibility and regression. We derive the asymptotic distribution of autocovariance function and estimators of the parameters in the suggested model. We also consider the relationship between INMA(q) and M/D/.infty. processes.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.616-618
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• 2002

본 논문에서는 음성인식 성능을 높이기 위한 기본적 단계인 음성과 비음성 부분의 경계를 추출하는 음성 경계 추출 방법을 제안한다. 음성경계 추출을 위한 특징들로는 시간영역 분할 파라미터인 ZCR, MA를 사용하고 주파수 영역 분할 파라미터로 주파수 대역 파워 에너지 (Frequency band power energy), 포만트 계수 (Formant coefficient)를 사용하였고 각 파라미터들을 이용하여 음성 경계를 결정할 때 경험에 의해 임계치를 결정하는 단점을 보안하기 위해서 신경망을 이용한다. 신경망의 가중치와 임계치들은 지도 학습을 통해 최적화 되고, 학습을 통해 구성된 망을 음성과 비음성의 경계치 구분에 사용한다.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1255-1267
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• 2018

Parasitic parameters have a larger influence on Silicon Carbide (SiC) devices with an increase of the switching frequency. This limits full utilization of the performance advantages of the low switching losses in high frequency applications. By combining a theoretical analysis with a experimental parametric study, a mathematic model considering the parasitic inductance and parasitic capacitance is developed for the basic switching circuit of a SiC MOSFET. The main factors affecting the switching characteristics are explored. Moreover, a fast-switching double pulse test platform is built to measure the individual influences of each parasitic parameters on the switching characteristics. In addition, guidelines are revealed through experimental results. Due to the limits of the practical layout in the high-speed switching circuits of SiC devices, the matching relations are developed and an optimized layout design method for the parasitic inductance is proposed under a constant length of the switching loop. The design criteria are concluded based on the impact of the parasitic parameters. This provides guidelines for layout design considerations of SiC-based high-speed switching circuits.

• Steel and Composite Structures
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• v.36 no.5
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• pp.533-551
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• 2020

A finite element analysis (FEA) model is established to investigate the concrete-encased concrete-filled steel tubular (CFST) column to reinforced concrete (RC) beam joints under cyclic loading. The feasibility of the FEA model is verified by a set of test results, consisting of the failure modes, the exposed view of connections, the crack distributions and development, and the hysteretic relationships. The full-range analysis is conducted to investigate the stress and strain development process in the composite joint by using this FEA model. The internal force distributions of different components, as well as the deformation distributions, are analyzed under different failure modes. The proposed connections are investigated under dimensional and material parameters, and the proper constructional details of the connections are recommended. Parameters of the beam-column joints, including material strength, confinement factor, reinforcement ratio, diameter of steel tube to sectional width ratio, beam to column linear bending stiffness ratio and beam shear span ratio are evaluated. Furthermore, the key parameters affecting the failure modes and the corresponding parameters ranges are proposed in this paper.

• The KSFM Journal of Fluid Machinery
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• v.19 no.4
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• pp.5-12
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• 2016

In this study, a parametric study on a cavity as casing treatment of a centrifugal compressor has been conducted using three-dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model. Two kinds of cavity were applied at choke and surge conditions, respectively, in this work. Inlet and outlet port widths, angle of outlet port, and length of cavity were chosen as the geometric parameters and investigated to find their effects on the aerodynamic performances such as adiabatic efficiency at design mass flow rate and stall margin of the centrifugal compressor. It was found that the aerodynamic performances of the centrifugal compressor were affected considerably by the four geometric parameters. The adiabatic efficiency was hardly changed by the geometric parameters, excepts for the angle of outlet port. With an increase in the angle of outlet port, the adiabatic efficiency and the stall margin decreased. The stall margin was more sensitive to the outlet port width than to the other geometric parameters. And, with a decrease in the outlet port width, the stall margin increased by 2% compared to that of the reference.