• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.143-153
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• 2015

In this paper, the standard fire resistance test under load and associated numerical study were carried out to evaluate the fire resistance of unprotected partially encased beams and slimfloor beams. The temperature evolution and the deflection increase of the composite beam specimens were investigated and the effects of the key behavioral parameters including the load ratio, the reinforcement, and the fire exposure were analyzed. The test results showed that the temperature rise of the partially encased beams and slimfloor beams is considerably slow compared to the conventional H-shape composite beams. Up to at least 90 minutes, the reinforcements in the partially encased composite beams maintained below the temperature at which the cold steel strength is sustained. Unprotected partially encased beams and slimfloor beams in the experimental program achieved the fire resistance more than 2 hours according to the limiting deflection criteria. This implies that unprotected partially encased beams and slimfloor beams can be very promising alternatives to enhancing the fire resistance of steel beams. This study also conducted the fully coupled thermal-stress analysis by using the commercial code ABAQUS to the thermal and structural behaviour of composite beams in fire. The numerical predictions provide acceptable correlations with the experimental results.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.109-117
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• 2020

This study aimed to develop an analytical method for determination of 18 dyes in livestock and fishery products by liquid chromatograph-tandem mass spectrometry (LC-MS/MS). The developed method was validated for linearity, accuracy, limit of quantifications (LOQ) and recovery based on the CODEX guideline (CAC/GL-71). Target matrices (beef, pork, chicken, egg, milk, flatfish, eel, and shrimp) were extracted using acetonitrile (containing 1% of acetic acid) and then, purified with C₁₈ and primary secondary amine (PSA). Calibration linearity was obtained (r²>0.98) and LOQs were 0.002 mg/kg in animal products. The recoveries of dyes were ranged from 63 to 112% and relative standard deviations (RSDs, %) were less than 15%. The residues of 18 dyes were investigated in real samples (n=124) collected from retail markets in South Korea. As a result, a total of seven samples showed positive results for target analytes in fish samples. However, there was no violation according to the maximum residue limits set by the Korean Food Code. The proposed method will be used for routine analysis of dye residues in livestock and fishery products.

• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.509-516
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• 2012

The aims of this research is to develop a fire resistant admixture to enhance high-pressured pumping of high-strength concrete (HSC) with a compressive strength of 60~80 MPa. Generally, the efficiency of HSC high-pressured pumping is dramatically reduced due to entanglement of short fibers added to prevent fire spalling. Therefore, the fire resistant admixture that can facilitate pumping of fire resistant HSC is urgently needed presently. The fire resistant HSC mix is comprised of Polypropylene fiber, Nylon fiber and Polymer powder. The test results showed that the slump-flow was improved by approximately 70% of the HSC without fire resistant admixture. However, the air void content was increased slightly due to the addition. The standard design compressive strength at 28-days was satisfied, while its flexural strength was similar to the concrete without the admixture. Since the flexural strength was 12~15% of its compressive strength, the general trend of flexural to compressive strength ratio in normal concrete was maintained. Even though its elastic modulus was decreased by adding the admixture, the study results showed that the concrete can be used for construction since all of the test results exceeded the code requirements.

• Journal of the Korea Concrete Institute
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• v.25 no.6
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• pp.593-599
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• 2013

The unrestrained shrinkage strain of alkali-activated (AA) slag concrete was examined and compared with design equations specified in code provisions and empirical equations proposed by Yang et al. The main parameters investigated were the water-to-binder ratio (W/B), unit water content and fine aggregate-to-total aggregate ratio (S/a). Test results revealed that shrinkage strain of AA slag concrete is nearly proportional to the W/B ratio, whereas its time function is independent of the W/B ratio. The shrinkage strain of AA slag concrete increased significantly when the unit water content is above $185kg/m^3$, whereas it is marginally affected by the S/a ratio. The design equation of ACI 209 considerably overestimates the shrinkage behavior of AA slag concrete, whereas CEB-FIP equation tends to underestimate the shrinkage at the age more than 28 days. The empirical equation of Yang et al. is in better agreement with test results, showing that values of mean and standard deviation of error coefficients obtained from each specimen are 016 and 0.07, respectively.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.497-508
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• 2013

This paper introduces a numerical model which can evaluate the fire-resistant capacity of reinforced concrete members. On the basis of the transient heat transfer considering the heat conduction, convection and radiation, time-dependent temperature distribution across a section is determined. A layered fiber section method is adopted to consider non-linear material properties depending on the temperature and varying with the position of a fiber. Furthermore, effects of non-mechanical strains of each fiber like thermal expansion, transient strain and creep strain are reflected on the non-linear structural analysis to take into account the extreme temperature variation induced by the fire. Analysis results by the numerical model are compared with experimental data from the standard fire tests to validate an exactness of the introduced numerical model. Also, time-dependent changes in the resisting capacities of reinforced concrete members exposed to fire are investigated through the analyses and, the resisting capacities evaluated are compared with those determined by the design code.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.131-142
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• 2005

The low rate speech coders under 4 kbit/s are based on sinusoidal transform coding (STC) or multiband excitation (MBE). Since the harmonic coders are not efficient to reconstruct the transient segments of speech signals such as onsets, offsets, non-periodic signals, etc, the coders do not provide a natural speech quality. This paper proposes method of a efficient transient model :d a multi-mode low rate coder at 2.4 kbit/s that uses harmonic model for the voiced speech, stochastic model for the unvoiced speech and a model using aperiodic pulse location tracking (APPT) for the transient segments, respectively. The APPT utilizes the harmonic model. The proposed method uses different models depending on the characteristics of LPC residual signals. In addition, it can combine synthesized excitation in CELP coding at time domain with that in harmonic coding at frequency domain efficiently. The proposed coder shows a better speech quality than 2.4 kbit/s version of the mixed excitation linear prediction (MELP) coder that is a U.S. Federal Standard for speech coder.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.280-290
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• 2018

This study was a non-equivalence-based Quasi experimental study comparing the difference in communication ability, emotional intelligence (EQ), self-esteem, and interpersonal abilities between an experimental group with communication training and a non-control group. The subjects of the study were nurses working for D university hospital located in C city and comprised an experimental group of 21 people and a control group of 21 people. From April to May 2017, the experimental group took communication training programs, which were designed to improve communication capacity, emotional intelligence, self-esteem, and interpersonal ability for a total of four sessions (for 2 hours a week), and pre-post examination was conducted for the validity of the study. For data analysis, the SPSS for Windows 23 was used for the mean and standard deviation of pre-post tests, and U-test of the independent sample Mann-Whitney and the Wilcoxon code order test of the corresponding sample were carried out. The study results indicate that, compared with the control group, the experimental group showed communication capacity (Z=-3.361, p<.05), emotional intelligence (Z=-2.209, p<.05), self-esteem (Z=-1.633, p<.05), and interpersonal relationship (Z=-2.577, p<.05). After the communication training program, scores of communication capacity, emotional intelligence (EQ), self-esteem, and interpersonal competence of the experimental group increased significantly, and all hypotheses were supported. These results suggest that nurses' use of communication training experience in performing nursing work in a clinical setting would improve communication skills, emotional intelligence (EQ), self-esteem, and interpersonal skills and provide therapeutic communication and effective nursing, thereby enhancing patients' satisfaction and contributing to the improvement of nursing quality.

• The Journal of the Acoustical Society of Korea
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• v.20 no.6
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• pp.34-39
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• 2001

An adaptive multi-rate (AMR) speech coder was adopted as a standard of W-CDMA by 3GPP and ETSI. The AMR coder is based on the CELP algorithm operating at rates ranging from 12.2 kbps down to 4.75 kbps, and it is a source controlled codec according to the channel error conditions and the traffic loading. In this paper, we implement the DSP S/W of the AMR coder using OakDSPCore. The implementation is based on the CSD17C00A chip developed by C&S Technology, and it is tested using test vectors, for the AMR speech codec, provided by ETSI for the bit exact implementation. The DSP B/W requires 20.6 MIPS for the encoder and 2.7 MIPS for the decoder. Memories required by the Am coder were 21.97 kwords, 6.64 kwords and 15.1 kwords for code, data sections and data ROM, respectively. Also, actual sound input/output test using microphone and speaker demonstrates its proper real-time operation without distortions or delays.

• The Journal of Information Systems
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• v.27 no.1
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• pp.193-224
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• 2018

Purpose Targeting Korean companies listed on Korean securities markets (i.e., KOSPI and KOSDAQ markets), this study aims to shed lights the effects of personal information security breaches on stock prices of information security companies. Interestingly, this study is, to the best of our knowledge, the first to examine the information transfer effect on personal information security breaches of companies. Design / Methodology /Approach To examine the information transfer effect of personal information security breaches, our study employs the event study commonly used in financial studies. To this end, we investigate a variety of events of personal information security breaches of companies listed on the KOPSI stock market and the KOSDAQ market. We collect the total samples of one hundred and twelve with forty seven of events of personal information security breaches by thirty companies and sixty five of information security companies. Findings The principal findings from the empirical study are as follows. First, for companies of personal information security breaches, our event study presents the significantly negative AAR (averaged abnormal return) value on the event day at the 5 % level and the highly significant negative CAAR(cumulative averaged abnormal return) value on the event day and the day after the event day at the 1 % level. The results suggest that personal information breaches significantly contribute to an decrease in value of the information breached companies. The cross sectional regressions in this study estimate the significantly negative coefficient for the ME/BE variable, the proxy for a growth opportunity at the 5 % level. This suggests a reverse relation between the growth opportunity of companies and their value. As for the various samples of the information security companies categorized by physical security, network and system security, security application software, code authentication, system integration, we find the significantly positive AAR on the day after the event day at the 5% level, only for the network and system security-companies. This addresses that the information transfer effect followed by personal information breaches is uniquely observable for companies categorized into network and system companies. The regressions for the network and system companies estimate the significantly positive coefficient for the NS dummy variable (i.e., the dummy of the network and system security companies) at the standard level. This allows us to identify appropriate times needed to make the information transfer effect realized from personal information breached companies to information security companies.

• Journal of Acupuncture Research
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• v.32 no.3
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• pp.95-105
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• 2015

Objectives : The purpose of this study is to review the characteristics of patients who visited the emergency room of a Korean medical hospital with musculoskeletal disorders during the last 5 years and to provide a potential basis for future studies and emergency medical practice. Methods : Patient visit records between May 1st, 2010 and February 28th, 2015 were reviewed and patients with musculoskeletal disorders were included in a retrospective analysis. Results : A total of 5,218 patient visit records were initially reviewed and 1,485 patients (28.46 %) were included in the analysis. S code group was the most frequently diagnosed coding group of Korean Standard Classification of Diseases. The male to female ratio was 1.05:1 and patients in their thirties represented the highest age group. When classified by time of visit, the distribution of patients was similar from 10:00 to 22:59. The most frequently visited day and month were Sunday and September. 879 patients (59.19 %) visited the emergency room within 24 hours from onset of symptoms. The most common symptom site was the low back (45.59 %), followed by ankle (13.94 %) and neck (13.80 %). The most frequently used treatment method was acupuncture (92.32 %), followed by infrared (45.45 %), TENS (30.03 %) and herbal medication (29.02 %). The follow-up and admission rates were 30.24 % and 13.00 % respectively. 343 patients (23.10 %) received Western medical treatment within a day before visiting the emergency room of the Korean medical hospital. Conclusions : This analysis provides the latest information on the characteristics of patients who visited the emergency room of a Korean medical hospital with musculoskeletal disorders. The results can provide the basis for further studies and for other attempts to improve the clinical setting of the emergency room.