• Title/Summary/Keyword: cause of the negative

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Control Strategy for Three-Phase Grid-Connected Converters under Unbalanced and Distorted Grid Voltages Using Composite Observers

  • Nguyen, Thanh Hai;Lee, Dong-Choon
    • Journal of Power Electronics
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    • v.13 no.3
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    • pp.469-478
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    • 2013
  • This paper proposes a novel scheme for the current controller for the grid-side converter (GSC) of permanent-magnet synchronous generator (PMSG) wind turbines to eliminate the high-order harmonics in the grid currents under grid voltage disturbances. The voltage unbalance and harmonics in three-phase systems cause grid current distortions. In order to mitigate the input current distortions, multi-loop current controllers are applied, where the positive-sequence component is regulated by proportional-integral (PI) controllers, and the negative-sequence and high-order harmonic components are regulated by proportional-resonance (PR) controllers. For extracting the positive/negative-sequence and harmonic components of the grid voltages and currents without a phase delay or magnitude reduction, composite observers are applied, which give faster and more precise estimation results. In addition, an active damping method using PR controllers to damp the grid current component of the resonant frequency is employed to improve the operating stability of VSCs with inductor-capacitor-inductor (LCL) filters. The validity of the proposed method is verified by simulation and experimental results.

Employee's Negative Psychological Factors Based on Excessive Workloads and Its Solutions Using Consultation with the Manager

  • PARK, Hye-Ryoung;KIM, Seong-Gon
    • East Asian Journal of Business Economics (EAJBE)
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    • v.10 no.1
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    • pp.59-69
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    • 2022
  • Purpose - Burnouts cause the workers to quit their jobs because with the heavy workloads that the employees get subjected to, they feel that they have little control over what they have to accomplish in the workplace. The purpose of this research is to provide adequate solutions using brief consultation process, reducing negative psychological factors. Research design, Data, and methodology - The current research conducted the 'Qualitative Content Analysis' (QCA), which is one of the most employed analytical tools; it has been used widely all over the globe in various research applications in library science and information. Primarily, this analysis is often used as a method in the quantitative tool until the recent decade. Result - Based on ultimate systematic literature analysis, excessive workloads can get addressed by finding proper solutions to the issues of depression, anxiety, irritability, and discouragement. The solutions are (1) Combating Excessive Workloads using Effective Employee Selection, (2) Employee Effective training, and (3) Job redesigning. Conclusion - Selecting or recruiting employees that have skills for the given job also makes it possible for the organization to run its employees effectively and with minimal cases of workload as an organization understands the capabilities and capacities of workload an employee can complete.

The Effect of Technostress on Counterproductive Work Behavior (테크노스트레스가 반생산적 과업행동에 미치는 영향)

  • Lee, Jaekang;Park, Taekyung
    • Journal of Information Technology Services
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    • v.14 no.4
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    • pp.1-14
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    • 2015
  • Due to advances in information and communication technologies (ICTs) and the advent of the Smartphone, people have access to the internet and can work at any time and any where. These are however likely to cause negative effects such as the personal information leakage and invasion of privacy. Caused by negative aspects of ICTs, the stress is so-called technostress. Recently, it is reported that managers tend to task order to their subordinates using an SNS or mobile messenger on a real-time basis after office hours or even on holiday, leading to a sharp increase in technostress. While previous studies of stress indicate that it is associated with the counter-productive work behavior (CWB), no empirical evidence has shown about the relationship between technostress and CWB. This study aims to explore the effect of technostress on CWB. In addition, it seeks to clarify the moderating effect of leader-member exchange(LMX) in this relationship. Drawing on literature regarding technostress and CWB, hypotheses are developed and tested with the sample of 101 using regression analyses. Results show that technostress has a significantly positive effect on CWB, but LMX has an insignificant moderating effect in the relationship between technostress and CWB. Implications and limitations with suggestions for future studies are presented.

Effectiveness of non-linear fluid viscous dampers in seismically isolated buildings

  • Guler, Elif;Alhan, Cenk
    • Earthquakes and Structures
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    • v.17 no.2
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    • pp.191-204
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    • 2019
  • Near-field earthquake records including long-period high-amplitude velocity pulses can cause large isolation system displacements leading to buckling or rupture of isolators. In such cases, providing supplemental damping in the isolation system has been proposed as a solution. However, it is known that linear viscous dampers can reduce base displacements in case of near-field earthquakes but at the potential expense of increased superstructure response in case of far-field earthquakes. But can non-linear dampers with different levels of non-linearity offer a superior seismic performance? In order to answer this question, the effectiveness of non-linear viscous dampers in reducing isolator displacements and its effects on the superstructure response are investigated. A comparison with linear viscous dampers via time history analysis is done using a base-isolated benchmark building model under historical near-field and far-field earthquake records for a wide range of different levels of non-linearity and supplemental damping. The results show that the non-linearity level and the amount of supplemental damping play important roles in reducing base displacements effectively. Although use of non-linear supplemental dampers may cause superstructure response amplification in case of far-field earthquakes, this negative effect may be avoided or even reduced by using appropriate combinations of non-linearity level and supplemental damping.

Predictive Value of Baseline Plasma D-dimers for Chemotherapy-induced Thrombocytopenia in Patients with Stage III Colon Cancer: A Pilot Study

  • Tanriverdi, Ozgur
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.293-297
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    • 2013
  • Background: : Chemotherapy-induced thrombocytopenia (CIT) is an important cause of morbitity in patients with cancer. Aim: To investigate the effect of the baseline plasma D-dimer level, an important marker for thrombotic activity, on chemotherapy-induced thrombocytopenia in patients with stage III colon cancer. Materials and Methods: A total of 43 (28 men) eligible patients were divided into two groups according to whether they exhibited chemotherapy-induced thrombocytopenia: Group 1 (n=21) and Group 2 (n=22). Comparison was made using demographic, histopathologic, and laboratory variables. Additionally, baseline plasma D-dimer levels underwent receiver operation characteristics curve analysis, and areas under the curve were calculated. Sensitivity, specificity, and positive and negative likelihood rates were then determined. Results: The incidence of chemotherapy-induced thrombocytopenia had a significant correlation with baseline platelet count (r=0.568, P=0.031) and baseline plasma D-dimer levels (r=0.617, P=0.036). When the cut-off point for the latter was set as 498 ng/mL, the area under the curve was 0.89 (95%CI: 0.74-0.93), the sensitivity was 91.4%, the specificity was 89.7%, the positive likelihood rate was 3.64 and the negative likelihood rate was 0.24 for chemotherapy-induced thrombocytopenia diagnosis. Conclusions: The baseline level of plasma D-dimer could help to differentiate high-risk patients for chemotherapy-induced thrombocytopenia.

Acute Osteomyelitis of the Mandible by Extended-Spectrum β-Lactamase Producing Klebsiella Pneumoniae: A Case Report

  • Jung, Gyeo-Woon;Moon, Seong-Yong;Oh, Ji-Su;Choi, Hae-In;You, Jae-Seek
    • Journal of Oral Medicine and Pain
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    • v.46 no.3
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    • pp.88-92
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    • 2021
  • Acute osteomyelitis caused by Klebsiella pneumoniae is rare in the oral and maxillofacial region. Klebsiella pneumoniae is a Gram-negative bacillus and the normal flora of the human body, but it can cause pneumonia, urinary tract infection, meningitis, and osteomyelitis in patient with compromised immune systems. These infections are mainly caused by nosocomial infection. Microbacterial osteomyelitis was developed by clinical cause such as tooth extraction, fracture, and surgical history, which requires long-term antibiotic administration and surgical treatment. This report describes that a 56-year-old male patient with acute osteomyelitis caused by Klebsiella pneumoniae infection after implant placement was treated with intravenous administration of ertapenem without open surgery treatment. Through this case, we report that antibiotic susceptibility test is essential for the treatment of acute osteomyelitis caused by a bacterial infection resistant to empirical antibiotics, and early administration of appropriate antibiotics can reduce the possibility of extensive bone destruction or additional open surgery.

Comparative Analysis on the Capital Structure of Superior Hospital and Bankrupt Hospital (우량병원과 도산병원의 자본구조 비교분석)

  • Ahn, Young-Chang;Kim, Jai-Myung;Ham, U-Sang
    • Korea Journal of Hospital Management
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    • v.11 no.4
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    • pp.19-36
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    • 2006
  • This study aims to examine the influence of growth rate, profitability and current ratio, which are confronted with static trade-off theory and pecking order theory, on capital structure of superior hospital and bankrupt hospital. Firstly, superior hospitals show positive correlation between growth rate and short-term loans, long-term loans, and short-term liabilities while bankrupt hospitals represent negative correlation. Superiority hospital and bankruptcy hospital show different financing behaviors, especially, short-term loan is the significant characteristic that discriminates between superior hospital and bankrupt hospital. Secondly, this paper studied the correlation between profitability and short-term loan, which the superior hospitals shows negative correlation, to contrast, bankrupt hospital have positive correlation. Consequently, the short-term loan is the most distinguishable factor between the superior hospital and bankrupt hospitals in terms of profitability. To conclude, this study shows that excess short-term loans can be the most important cause for hospital's bankrupt. Accordingly, strategic and effective policy about the short-term loan will be required in order to protect hospital's bankrupt.

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Catheter-related bloodstream infections in neonatal intensive care units

  • Lee, Jung-Hyun
    • Clinical and Experimental Pediatrics
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    • v.54 no.9
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    • pp.363-367
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    • 2011
  • Central venous catheters (CVCs) are regularly used in intensive care units, and catheter-related bloodstream infection (CRBSI) remains a leading cause of healthcare-associated infections, particularly in preterm infants. Increased survival rate of extremely-low-birth-weight infants can be partly attributed to routine practice of CVC placement. The most common types of CVCs used in neonatal intensive care units (NICUs) include umbilical venous catheters, peripherally inserted central catheters, and tunneled catheters. CRBSI is defined as a laboratory-confirmed bloodstream infection (BSI) with either a positive catheter tip culture or a positive blood culture drawn from the CVC. BSIs most frequently result from pathogens such as gram-positive cocci, coagulase-negative staphylococci, and sometimes gram-negative organisms. CRBSIs are usually associated with several risk factors, including prolonged catheter placement, femoral access, low birth weight, and young gestational age. Most NICUs have a strategy for catheter insertion and maintenance designed to decrease CRBSIs. Specific interventions slightly differ between NICUs, particularly with regard to the types of disinfectants used for hand hygiene and appropriate skin care for the infant. In conclusion, infection rates can be reduced by the application of strict protocols for the placement and maintenance of CVCs and the education of NICU physicians and nurses.

A Study on Health-Risk Behavior of Adolescent Smoking (청소년의 흡연에 관한 건강위험행위 연구 -서울시 일부 고등학생을 중심으로-)

  • 이선영;이시백
    • Korean Journal of Health Education and Promotion
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    • v.17 no.2
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    • pp.17-33
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    • 2000
  • The aim of this study is having the status, knowledge and attitude of the high school attendees toward smoking be analyzed, helping to make effective health education methods to diminish adolescent smoking habits. The field self-questionnaire investigation has been performed from Oct 10th through 23rd in 1999. The whole 427 cases were distributed to 1st and 2nd grade students of randomly selected men's high school in Seoul. And 414 cases (97%) were finally selected for analysis after exclusion of cases with insufficient information. The main contents of questionnaire are composed of several sectors; the general characteristics of the interviewees, the relationship with parents, the life style and the peer relationship in school. And smoking-related characteristics are taken into consideration, too. The major findings of the study are as follows: The smoking/non-smoking related factors are, in socio-demographical terms, the grade, average spending per month of the interviewees. And the degree of satisfactory relationship with parents is significant on smoking behavior. The higher, the degree of satisfaction on school life and relationship with designated teacher, the more chances of non-smoking habit. Poor academic grades and peer group dependability of interviewees cause higher smoking habit rate in other way. The self-interviewees grade and cohabitation with parents are also significant on both the attitude toward smoking habit and the knowledge on smoking statistically. The academic history and vocations of the parents and the academic grades of interviewees are also effective variables, but don't make any gap between groups knowledge on smoking. Smoking groups used to have positive attitude toward smoking habit. Both the attitude and knowledge on smoking by the consideration of Quit-smoking have statistically significance. The groups which have negative attitude and high knowledge on smoking quit-smoking into consideration. And the primary cause of quit-smoking is on health by smoking. Depression, stress, adult smoking in the house, peer group pressure, cigarettes advertisements on papers and magazines and smoking scenes on TV have positive correlation on forming smoking habit (p〈0.001) But the knowledge on diseases triggered by smoking has negative correlation on forming smoking habit. (p〈0.05, p〈0.001). Social factors as monthly spending, relationship and communication with parents, the degree of satisfaction in school life, academic grades and student-teacher relationship have crucial negative correlation on smoking habit. That is to say, the higher, the monthly spending is, the worse, the relationship with parents and teachers is, the lower, the academic grades of the student is, the percentage of the interviewees who have smoking habit seems to get higher.

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Mastitis with Proteus mirabilis in Brittany Spaniel, a case (Brittany Spaniel에서 Proteus mirabilis에 의한 유방염 발생: 증례)

  • Lee, Jeong-Won;Chu, Keum-Suk;Kwak, Kil-Han;Ko, Won-Seuk;Song, Hee-Jong
    • Korean Journal of Veterinary Service
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    • v.32 no.3
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    • pp.215-218
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    • 2009
  • The dog breeding kennel bacterial infection are very significant in perinatal mortality. In many case, Staphylococcus aureus, Streptococcus, and Escherichia coli were infected in intra-uterine or by the genital tract to the puppies, and they are cause of septicemic death of the puppies and clinical mastitis of bitch, leading to septicemic death of newborn puppies. Severe mastitis due to bacterial infection was diagnosed in a 2 year-old female Brittany Spaniel which loss 6 puppies with odor small rice sharp white diarrhea of nine puppies. Bright curd milk and intestinal sample were inoculated on MacConkey agar, blood agar and brain heart infusion agar, and incubated at $37^{\circ}C$ for 24-48 hrs. Gram negative colonies isolated from these sample which were characterized as Glu, Ure, $H_2S$, Orn, Cit, and Cl, and were identified by Microscan Walk-Aways Baxter, American Type Culture Collection, USA) as Proteus mirabils. The isolate was more sensitive to ampicillin, gentamicin, cefoxitin, cefuroxime, and cefazidime. In this results, we confirmed that cause bacteria of septicemic death in puppies was P. mirabilis.