• Economic and Environmental Geology
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• v.27 no.6
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• pp.557-561
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• 1994

Q estimates are made by direct measurements of energy loss per cycle from primary P and S waves, as a function of frequency. Assuming that intrinsic Q is frequency independent and scattering Q is frequency dependent over the frequencies of interest, the relative contributions of each, to a total observed Q, may be estimated. Test examples are produced by computing viscoelastic synthetic seismograms using a pseudo spectral solution with inclusion of relaxation mechanisms (for intrinsic Q) and a fractal distribution of scatterers (for scattering Q). The composite theory implies that when the total Q for S-waves is smaller than that for P-waves (the usual situation), intrinsic Q is dominating; when it is larger, scattering Q is dominating. In the inverse problem, performed by a global least squares search, intrinsic $Q_p$ and $Q_s$ estimates are reliable and unique when their absolute values are sufficiently low that their effects are measurable in the data. Large $Q_p$ and $Q_s$ have no measurable effect and hence are not resolvable. Standard deviation of velocity $({\sigma})$ and scatterer size (A) are less unique as they exhibit a tradeoff as predicted by Blair's equation. For the P-waves, intrinsic and scattering contributions are of approximately the same importance, for S-waves, the intrinsic contributions dominate.

• Journal of Chest Surgery
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• v.34 no.6
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• pp.485-489
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• 2001

Background: The most important factor in preventing sternal complications is stable sternal approximation. We have tried to find the most effective sternal closure method by examining the incidence of sternal dehiscence with or without infection in patients with cardiac surgery through median sternotomy. Material and Method: This study was performed in 489 patients over 45 years of age with median sternotomy for open cardiac surgery. Simple closure with interrupted 6 wires was performed in 159 patients, figure-of-8 closure technique in 119, overlapping interrupted closure using 10 wires in 150, and combined closure technique of interrupted simple closure and figure-of-8 suture closure in 61. Two hundred thirty-four patients underwent valve and aortic operations and 213 patients coronary artery bypass surgery. Result: Sternal dehiscence with or without infection occurred in 12 (2.5 %) patients. The complication developed in 5 of 159 patients (3.1%) with six interrupted simple closure, in 4 of 119 patients (3.4%) with figure-of-8 closure, and in 3 of 150 patients (2.0%) with overlapping interrupted closure using 10 wires, but there was no complication in 61 patients with combined closure technique (relative risk for other closure techniques, p<0.05). There was no significant difference in the incidence of the sternal complication between valve and aortic operation group and coronary artery bypass group (3.0% vs 2.3%, not significant), but diabetes mellitus was a significant independent risk factor (odds ratio and multivariate analysis, p<0.05). Conclusion: The sternal closure technique that combines simple interrupted suture closure and figure-of-8 suture closure may be a more useful technique to enhance sternal stabilization compared to other closure techniques, such as simple interrupted closure, 8-figure closure, and overlapping interrupted closure.

• Journal of Veterinary Clinics
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• v.31 no.6
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• pp.469-476
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• 2014

The aims of this study were to explore the effects of conjugated linoleic acid (CLA) on reactive oxygen species (ROS) production in lipopolysaccharide (LPS)-naïve and LPS-stimulated RAW 264.7 macrophages and to examine whether these effects affect the regulation of tumor necrosis factor-alpha (TNF-${\alpha}$) production, and nuclear factor-kappa B (NF-${\kappa}B$) and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) activation. Trans-10, cis-12(t10c12)-CLA increased the production of ROS, as well as TNF-${\alpha}$ in LPS-naïve RAW 264.7 cells. The CLA-induced TNF-${\alpha}$ production was suppressed by treatment of diphenyleneiodonium chloride (DPI), a NADPH oxidase inhibitor. In addition, CLA enhanced the activities of NF-${\kappa}B$ and $PPAR{\gamma}$ in LPS-naïve RAW 264.7 cells, and this effect was abolished with DPI treatment. LPS treatment increased ROS production, whereas CLA reduced LPS-induced ROS production. LPS increased both TNF-${\alpha}$ production and NF-${\kappa}B$ activity, whereas t10c12-CLA reduced TNF-${\alpha}$ production and NF-${\kappa}B$ activity in LPS-stimulated RAW 264.7 cells. DPI treatment suppressed LPS-induced ROS production and NF-${\kappa}B$ activity. Moreover, DPI enhanced the inhibitory effects of t10c12-CLA on TNF-${\alpha}$ production and NF-${\kappa}B$ activation in LPS-stimulated RAW 264.7 cells. However, neither t10c12-CLA nor DPI affected $PPAR{\gamma}$ activity in LPS-stimulated RAW 264.7 cells. Taken together, these data indicate that t10c12-CLA induces TNF-${\alpha}$ production by increasing ROS production in LPS-naïve RAW 264.7 cells, which is mediated by the enhancement of NF-${\kappa}B$ activity via $PPAR{\gamma}$ activation. By contrast, t10c12-CLA suppresses TNF-${\alpha}$ production by inhibiting ROS production and NF-${\kappa}B$ activation via a $PPAR{\gamma}$-independent pathway in LPS-stimulated RAW 264.7 cells. These results suggest that t10c12-CLA can modulate TNF-${\alpha}$ production and NF-${\kappa}B$ activation through formation of ROS in RAW 264.7 macrophages.

• Asia pacific journal of information systems
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• v.19 no.4
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• pp.47-75
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• 2009

Recently, researches on Management Information Systems (MIS) have laid out theoretical foundation and academic paradigms by introducing diverse theories, themes, and methodologies. Especially, academic paradigms of MIS encourage a user-friendly approach by developing the technologies from the users' perspectives, which reflects the existence of strong causal relationships between information systems and user's behavior. As in other areas in social science the use of structural equation modeling (SEM) has rapidly increased in recent years especially in the MIS area. The SEM technique is important because it provides powerful ways to address key IS research problems. It also has a unique ability to simultaneously examine a series of casual relationships while analyzing multiple independent and dependent variables all at the same time. In spite of providing many benefits to the MIS researchers, there are some potential pitfalls with the analytical technique. The research objective of this study is to provide some guidelines for an appropriate use of SEM based on the assessment of current practice of using SEM in the MIS research. This study focuses on several statistical issues related to the use of SEM in the MIS research. Selected articles are assessed in three parts through the meta analysis. The first part is related to the initial specification of theoretical model of interest. The second is about data screening prior to model estimation and testing. And the last part concerns estimation and testing of theoretical models based on empirical data. This study reviewed the use of SEM in 164 empirical research articles published in four major MIS journals in Korea (APJIS, ISR, JIS and JITAM) from 1991 to 2007. APJIS, ISR, JIS and JITAM accounted for 73, 17, 58, and 16 of the total number of applications, respectively. The number of published applications has been increased over time. LISREL was the most frequently used SEM software among MIS researchers (97 studies (59.15%)), followed by AMOS (45 studies (27.44%)). In the first part, regarding issues related to the initial specification of theoretical model of interest, all of the studies have used cross-sectional data. The studies that use cross-sectional data may be able to better explain their structural model as a set of relationships. Most of SEM studies, meanwhile, have employed. confirmatory-type analysis (146 articles (89%)). For the model specification issue about model formulation, 159 (96.9%) of the studies were the full structural equation model. For only 5 researches, SEM was used for the measurement model with a set of observed variables. The average sample size for all models was 365.41, with some models retaining a sample as small as 50 and as large as 500. The second part of the issue is related to data screening prior to model estimation and testing. Data screening is important for researchers particularly in defining how they deal with missing values. Overall, discussion of data screening was reported in 118 (71.95%) of the studies while there was no study discussing evidence of multivariate normality for the models. On the third part, issues related to the estimation and testing of theoretical models on empirical data, assessing model fit is one of most important issues because it provides adequate statistical power for research models. There were multiple fit indices used in the SEM applications. The test was reported in the most of studies (146 (89%)), whereas normed-test was reported less frequently (65 studies (39.64%)). It is important that normed- of 3 or lower is required for adequate model fit. The most popular model fit indices were GFI (109 (66.46%)), AGFI (84 (51.22%)), NFI (44 (47.56%)), RMR (42 (25.61%)), CFI (59 (35.98%)), RMSEA (62 (37.80)), and NNFI (48 (29.27%)). Regarding the test of construct validity, convergent validity has been examined in 109 studies (66.46%) and discriminant validity in 98 (59.76%). 81 studies (49.39%) have reported the average variance extracted (AVE). However, there was little discussion of direct (47 (28.66%)), indirect, and total effect in the SEM models. Based on these findings, we suggest general guidelines for the use of SEM and propose some recommendations on concerning issues of latent variables models, raw data, sample size, data screening, reporting parameter estimated, model fit statistics, multivariate normality, confirmatory factor analysis, reliabilities and the decomposition of effects.

• Asia pacific journal of information systems
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• v.19 no.4
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• pp.77-100
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• 2009

Information Systems (IS) is an essential tool for any organizations. The last decade has seen an increasing body of knowledge on IS usage. Yet, IS often fails because of its misuse or non-use. In general, decisions regarding the selection of a system, which involve the evaluation of many IS vendors and an enormous initial investment, are made not through the consensus of employees but through the top-down decision making by top managers. In situations where the selected system does not satisfy the needs of the employees, the forced use of the selected IS will only result in their resistance to it. Many organizations have been either integrating dispersed legacy systems such as archipelago or adopting a new ERP (Enterprise Resource Planning) system to enhance employee efficiency. This study examines user resistance prior to the adoption of the selected IS or ERP system. As such, this study identifies the importance of managing organizational resistance that may appear in the pre-adoption context of an integrated IS or ERP system, explores key factors influencing user resistance, and investigates how prior experience with other integrated IS or ERP systems may change the relationship between the affecting factors and user resistance. This study focuses on organizational members' resistance and the affecting factors in the pre-adoption context of an integrated IS or ERP system rather than in the context of an ERP adoption itself or ERP post-adoption. Based on prior literature, this study proposes a research model that considers six key variables, including perceived benefit, system complexity, fitness with existing tasks, attitude toward change, the psychological reactance trait, and perceived IT competence. They are considered as independent variables affecting user resistance toward an integrated IS or ERP system. This study also introduces the concept of prior experience (i.e., whether a user has prior experience with an integrated IS or ERP system) as a moderating variable to examine the impact of perceived benefit and attitude toward change in user resistance. As such, we propose eight hypotheses with respect to the model. For the empirical validation of the hypotheses, we developed relevant instruments for each research variable based on prior literature and surveyed 95 professional researchers and the administrative staff of the Korea Photonics Technology Institute (KOPTI). We examined the organizational characteristics of KOPTI, the reasons behind their adoption of an ERP system, process changes caused by the introduction of the system, and employees' resistance/attitude toward the system at the time of the introduction. The results of the multiple regression analysis suggest that, among the six variables, perceived benefit, complexity, attitude toward change, and the psychological reactance trait significantly influence user resistance. These results further suggest that top management should manage the psychological states of their employees in order to minimize their resistance to the forced IS, even in the new system pre-adoption context. In addition, the moderating variable-prior experience was found to change the strength of the relationship between attitude toward change and system resistance. That is, the effect of attitude toward change in user resistance was significantly stronger in those with prior experience than those with no prior experience. This result implies that those with prior experience should be identified and provided with some type of attitude training or change management programs to minimize their resistance to the adoption of a system. This study contributes to the IS field by providing practical implications for IS practitioners. This study identifies system resistance stimuli of users, focusing on the pre-adoption context in a forced ERP system environment. We have empirically validated the proposed research model by examining several significant factors affecting user resistance against the adoption of an ERP system. In particular, we find a clear and significant role of the moderating variable, prior ERP usage experience, in the relationship between the affecting factors and user resistance. The results of the study suggest the importance of appropriately managing the factors that affect user resistance in organizations that plan to introduce a new ERP system or integrate legacy systems. Moreover, this study offers to practitioners several specific strategies (in particular, the categorization of users by their prior usage experience) for alleviating the resistant behaviors of users in the process of the ERP adoption before a system becomes available to them. Despite the valuable contributions of this study, there are also some limitations which will be discussed in this paper to make the study more complete and consistent.

• 한국노년학
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• v.37 no.1
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• pp.237-250
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• 2017

The purpose of this study is to analyze the effects of exercise program for prevention of falling on physical fitness, posture and fall prevention self-efficacy for elderly women. 30 females above the age of 65 were subjects for this study. Over an twelve week period, 14women in the experimental group performed exercise 2 times a week for 60 minutes per session. 16women in the control group didn't participate in the exercise program. The independent variable was a exercise program for prevention of falling. Dependent variables were physical fitness, posture and fall prevention self-efficacy. Prevention of falling exercise program is consisted of an elastic band using exercise and Korean dance movement exercise. Physical fitness consisted of grip strength, upper and lower body endurance, cardiovascular endurance, flexibility, balance, coordination. The posture was measured the static posture when standing, using a high-resolution camera, body style to automatically measure the distance and angle(M-zen, Korea). Posture was measured in both the coronal and sagittal plane via reference board. Fall prevention self-efficacy was measured via questionnaire using the Korea Falls Self-Efficacy Scale (FES-K). The physical fitness, posture and fall prevention self-efficacy were measured twice with pre and post exercise, and the difference between groups with Wilcox signed rank test, and the group-specific post verification was carried out with U-validated methods (Mann Whitney U test). Statistical significance level was verified by setting the p<.05. Lower body endurance, cardiovascular endurance, flexibility, balance and coordination significantly increased in the experimental group. The control group was no significant increase in physical fitness variables. shoulder slope angle, pelvic slope angle(coronal/sagittal), leg length difference, scapular inferior angle and left/right calcaneus angle significantly decreased in the experimental group. Both the experimental group and control group were no significant increase in fall prevention self efficacy. The prevention of falling exercise program for elderly women indicated the positive changes in physical fitness(except grip strength) and posture(except upper body slope). However, there are no significant differences of falling prevention self-efficacy between the both group. Thus, the prevention of falling exercise program for the elderly has been proved that it is highly efficient on improving physical fitness and posture proofreading. However, we still need to consider supplement exercise for grip strength and upper body slope.

• Journal of Korea Water Resources Association
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• v.52 no.11
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• pp.917-929
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• 2019

Denitrification in streams is of great importance because it is essential for amelioration of water quality and accurate estimation of $N_2O$ budgets. Denitrification is a major biological source or sink of $N_2O$, an important greenhouse gas, which is a multi-step respiratory process that converts nitrate ($NO_3{^-}$) to gaseous forms of nitrogen ($N_2$ or $N_2O$). In aquatic ecosystems, the complex interactions of water flooding condition, substrate supply, hydrodynamic and biogeochemical properties modulate the extent of multi-step reactions required for $N_2O$ flux. Although water flow in streambed and residence time affect reaction output, effects of a complex interaction of hydrodynamic, geomorphology and biogeochemical controls on the magnitude of denitrification in streams are still illusive. In this work, we built a two-dimensional water flow channel and measured $N_2O$ flux from channel sediment with different bed geomorphology by using static closed chambers. Two independent experiments were conducted with identical flume and geomorphology but sediment with differences in dissolved organic carbon (DOC). The experiment flume was a circulation channel through which the effluent flows back, and the size of it was $37m{\times}1.2m{\times}1m$. Five days before the experiment began, urea fertilizer (46% N) was added to sediment with the rate of $0.5kg\;N/m^2$. A sand dune (1 m length and 0.15 m height) was made at the middle of channel to simulate variations in microtopography. In high- DOC experiment, $N_2O$ flux increases in the direction of flow, while the highest flux ($14.6{\pm}8.40{\mu}g\;N_2O-N/m^2\;hr$) was measured in the slope on the back side of the sand dune. followed by decreases afterward. In contrast, low DOC sediment did not show the geomorphological variations. We found that even though topographic variation influenced $N_2O$ flux and chemical properties, this effect is highly constrained by carbon availability.

• Food Science and Preservation
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• v.19 no.4
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• pp.470-476
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• 2012

Enzymatic action and microbial growth degrade the quality of fresh-cut lettuce. Browning, a bad smell, and softening during storage are the major forms of quality deterioration. Health-oriented consumers tend to avoid foods treated with chemicals to maintain their freshness. This study was conducted to evaluate the change in the quality of fresh-cut lettuce with combined low-temperature blanching (LB) and ultrasonication (US). The optimum condition was selected using the response surface methodology (RSM), through a regression analysis with the following independent variables; the ultrasonication time (X1), blanching temperature (X2), blanching time (X3), and dependent variable; ${\Delta}E$ value (y). It was found that the condition with the lowest ${\Delta}E$ value occurred with combined 90s US and $45^{\circ}C$ 90s LB (US+LB). The combined treatment group (US+LB) was stored at $10^{\circ}C$ for 9 days with the control group and each single-treatment group, with low-temperature blanching and ultrasonication. Overall, the US+LB group had a significantly high $L^*$ value, which indicates significantly low $a^*$, $b^*$, ${\Delta}E$, browning index, PPO, and POD activity values, and a low total bacteria count (p < 0.05). The US+LB group also had the highest sensory score (except for aroma and texture; p > 0.05).

• Land and Housing Review
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• v.12 no.2
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• pp.47-59
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• 2021

This study aims to review the trends of the population outflows in the metropolitan area of Busan and to investigate the factors that affect population out-migration to the Seoul metropolitan area. The following variables are considered for analysis: traditional population movement variables and quality of life variables, such as population, society, employment, housing, culture, safety, medical care, greenery, education, and childcare. The 'domestic population movement data', provided by the MDIS of the National Statistical Office, was used for this research. Out of the total of 57 million population movement data in the period 2012 - 2017, population outmigration from Busan to the Seoul metropolitan area was extracted. Independent variables were drawn from public data sources in accordance with the temporal and spatial settings of the study. The multiple linear regression model was specified based on the dataset, and the fit of the model was measured by the p-value, and the values of Adjusted R2, Durbin-Watson analysis, and F-statistics. The results of the analysis showed that the variables that have a significant effect on population movement from Busan to the Seoul metropolitan area were as follows: 'single-person households', 'the elderly population', 'the total birth rate', 'the number of companies', 'the number of employees', 'the housing sales price index', 'cultural facilities', and 'the number of students per teacher'. More positive (+) influences of the population out-movement were observed in areas with higher numbers of single-person households, lowers proportions of the elderly, lower numbers of businesses, higher numbers of employees, higher numbers of housing sales, lower numbers of cultural facilities, and lower numbers of students. The findings suggest that policies should enhance the environments such as quality jobs, culture, and welfare that can retain young people within Busan. Improvements in the quality of life and job creation are critical factors that can mitigate the outflows of the Busan residents to the Seoul metropolitan area.

• Journal of Korean Philosophical Society
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• v.147
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• pp.333-356
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• 2018

Shang Yang was a person who, as a representative of the former School of Law, not only had an effect of thought on Han Fei Tzu, but also put a cornerstone of Qin Shi Huang's great universal unification by placing small and weak Qin Dynasty in a border area in the rank of a newly rising powerful nation. He is especially regarded as a person who valued laws and established the theoretical framework of legalist thought of School of Law systematically. To begin with, this writing examines the contents of the enforcement of legal reforms relevant to the prerequisite of Shang Yang's legal thought in historical archives, and confirms that Shang Yang succeeded in accomplishing legal reforms twice and that the aim of the legal reforms was to realize national prosperity and military power for the universal unification. This writing also takes notice of the fact that Shang Yang's legal thought went through specific steps for unifying the legal authority and the power of the monarch. Especially this writing focuses on applying the three-step theory of norms that was presented in the western social and political norm theory to Shang Yang's legal thought and on examining the characteristic and meaning explicitly. In short, the social and political norms go through emergence, cascade, and internalization. This writing aims to confirm that Shang Yang's legal thought also went through these three steps and was specified. Specifying this critical mind, this writing is a result which discusses that Shang Yang's legal thought went though the steps of the selective prescriptivism of emergence, the monarchical absolutism through sever punishment, and the internal monarchism for national prosperity and military power, and that the thought was systemized. Finding that the contents of Shang Yang's legal thought correspond to the three-step theory of norms and produce the individual meaning is the independent characteristic of this writing. It is the aim of this writing that the system and meaning of Shang Yang's legal thought will be confirmed more explicitly through this contextual examination.