• Journal of Elementary Mathematics Education in Korea
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• v.10 no.1
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• pp.43-66
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• 2006

This study was proposed to analyze mathematical communication activity and mathematical attitudes while students were solving project problem and to consider how the conclusions effects mathematics education. This study analyzed through qualitative research method. The questions for this study are following. First, how does the process of the mathematical communication activity proceed during solving project problem in a small group? Second, what reactions can be shown on mathematical attitudes during solving project problem in a small group? Four project problems sampled from pilot study in order to examine these questions were applied on two small groups consisting of four 5th grade students It was recorded while each group was finding out the solution of the given problems. Afterward, consequences were analyzed according to each question after all contents were noted. Consequently, conclusions can be derived as follows. First, it was shown that each student used different elements of contents in mathematical communication activity. Second, during mathematical communication activity, most students preferred common languages to mathematical ones. Third, it was found that each student has their own mathematical attitude. Fourth, Students were more interested in the game project problem and the practical using project problem than others.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.791-795
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• 2005

A simulation model is proposed to evaluate the effect of correlations between activity durations on the overall project duration. The proposed model incorporates NORTA, a recent developed statistical method, into the simulation process to allow arbitrarily specified marginal distributions for activity durations and any desired correlation structure. The generality is of practical value when systematic data is not available and planners have to rely on arbitrary experts' estimation, which may involve a mixed situation when some activity durations are continuously distributed whereas others are discrete outcomes. The proposed model is validated by showing that the correlation coefficients of the simulation results are close to the originally specified ones. The simulation results are compared to two conventional approaches: PERT and simulation without correlation. The comparisons illustrate that the proposed model can provide important management information, which would otherwise be distorted due to the neglect of the correlations between activity durations.

• Molecular & Cellular Toxicology
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• v.4 no.1
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• pp.5-10
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• 2008

The effect of obesity on the drug-metabolizing enzymes remains an important issue for clinician since obesity is a world wide epidemic problem. However, little is known about the effects of obesity on flavincontaining monooxygenase (FMO) production and activity. We show here for the first time that in vivo FMO activity determined by urinary ranitidine (RA) metabolites ratio in human, was higher in subjects with a high body mass index (BMI, kg/$m^2$, 21.97-30.32) than in those with an intermediate BMI (range 19.38-21.83). Moreover, there was a significant correlation between FMO activity and BMI in 209 subjects. In high fat diet-induced obese mice, we also observed that the hepatic expression of FMO (225% of lean mice) and the activity measured by the RA Noxidation rate ($513{\pm}58.1$ vs. $349{\pm}66.0$ pmol/hr per mg protein) were significantly higher than in lean mice fed a control diet. Unknown factors rather than leptin or insulin appeared to regulate the hepatic FMO production. Thus, FMO activity may be increased in obese or overweight individuals. Moreover, the regulation of FMO activity in subjects with morbid obesity, with or without complications and its clinical implications, should be investigated further.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.359-366
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• 2013

Although many research efforts have been conducted to address the effect of crew members' work skills (e.g., technical and planning skills) on work performance (e.g., work duration and quality) in construction projects, the relationship between skill and performance has generated a great deal of controversy in the field of management (Inkpen and Crossan 1995). This controversy can lead to under- or over-estimations of the overall project schedule, and can make it difficult for project managers to implement appropriate managerial policies for enhancing project performance. To address this issue, the following aspects need to be considered: (a) work performances are determined not only by individual-level work skill but also by the group-level work skill affected by work team members, each member's role, and any working behavior pattern; (b) work planning has significant effects on to what extent work skill enhances performance; and (c) different types of activities in construction require different types of work, skill, and team composition. This research, therefore, develops a system dynamics (SD) model to analyze the effects of both individual-and group-level (i.e., multi-level) skill on performances by utilizing the advantages of SD in capturing a feedback process and state changes, especially in human factors (e.g., attitude, ability, and behavior). The model incorporates: (a) a multi-level skill evolution and relevant behavior development mechanism within a work group; (b) the interaction among work planning, a crew's skill-learning, skill manifestation, and performances; and (c) the different work characteristics of each activity. This model can be utilized to implement appropriate work planning (e.g., work scope and work schedule) and crew management policies (e.g., work team composition and decision of each worker's role) with an awareness of crew's skill and work performance. Understanding the different characteristics of each activity can also support project managers in applying strategic work planning and crew management for a corresponding activity, which may enhance each activity's performance, as well as the overall project performance.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.575-581
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• 2011

A novel approach for analysis of criticality with respect to path and to activity in networks with fuzzy activity durations is proposed. After recalling the Yager ranking method, the relative degree of criticality of activities and paths are defined. An efficient algorithm based on path enumeration to compute the relative degree of criticality of activities and paths in networks with fuzzy durations is proposed. Examples of former researches are employed to validate the proposed approach. The proposed algorithm has been tested on real world project networks and experimental results have shown that the algorithm can calculate the relative degree of criticality of activities and paths in a reasonable time.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1100-1106
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• 2009

General contractors' overhead costs are increasing relative to direct costs. However, it is difficult to apply the traditional activity-based costing directly to the construction site overhead costing because the resource consumption rate per each activity is varied depending on the attributes of activities. The research develops a methodology of hybrid cost allocation system when resources are assigned to cost objects unlike the traditional activity-based costing. The study also develops a database program and demonstrates how it can be applied to the construction projects using a case study.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.3
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• pp.137-149
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• 2005

This study proposes a framework enhancing the accuracy of estimation for project duration by combining linear Bayesian updating scheme with the learning curve effect. Activities in a particular project might share resources in various forms and might be affected by risk factors such as weather Statistical dependence stemming from such resource or risk sharing might help us learn about the duration of upcoming activities in the Bayesian model. We illustrate, using a Monte Carlo simulation, that for partially repetitive projects a higher degree of statistical dependence among activity duration results in more variation in estimating the project duration in total, although more accurate forecasting Is achievable for the duration of an individual activity.

• Korean Journal of Construction Engineering and Management
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• v.6 no.1 s.23
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• pp.73-79
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• 2005

This paper, introduces a Stochastic Project Scheduling Simulation system (SPSS III) developed by the author to predict a project completion probability in a certain time. The system integrates deterministic CPM, probabilistic PERT, and stochastic Discrete Event Simulation (DES) scheduling methods into one system. It implements automated statistical analysis methods for computing the minimum number of simulation runs, the significance of the difference between independent simulations, and the confidence interval for the mean project duration as well as sensitivity analysis method in What-if analyzer component. The SPSS 111 gives the several benefits to researchers in that it (1) complements PERT and Monte Carlo simulation by using stochastic activity durations via a web based JAVA simulation over the Internet, (2) provides a way to model a project network having different probability distribution functions, (3) implements statistical analyses method which enable to produce a reliable prediction of the probability of completing a project in a specified time, and (4) allows researchers to compare the outcome of CPM, PERT and DES under different variability or skewness in the activity duration data.

• Smart Media Journal
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• v.1 no.4
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• pp.79-83
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• 2012

In software development process, increasing the size of project(scaling up) is not a same problem as scaling up the parts of small project. Scaling up a project should accompany the communications, and cost, productivity, qualities, development activity, methodologies etc should be considered with it. In this paper, the effective usage of the important elements are discussed in order not to fail to scale up a project.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4007-4014
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• 2012

Efficient synthetic route to novel 4'-fluorinated 5'-deoxythreosyl phosphonic acid nucleosides was described from glyceraldehyde using Horner-Emmons reaction in the presence of triethyl ${\alpha}$-fluorophosphonoacetate. Glycosylation reaction of nucleosidic bases with glycosly donor 14 gave the nucleosides which were further phosphonated and hydrolyzed to reach desired nucleoside analogues. Synthesized nucleoside analogues 18, 21, 25 and 28 were tested for anti-HIV activity as well as cytotoxicity. Adenine derivatives 18 and 21 showed significant anti-HIV activity up to $100{\mu}M$.