• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.747-753
• /
• 2009

Planning the construction for a system of bored piles in building foundation engineering is (1) to predict the time duration required to complete all the bored piles with due consideration of relevant engineering factors and site constraints; then (2) to predict the total project time generally by aggregating the predicted working duration for construction of each bored pile. The duration for construction of an individual bored pile results from analyzing various working sequences and different activity duration (such as predrilling, excavation, steelfixing, air-lifting, and concreting, etc.), which is informed by experiences and site records of previous projects. However, determining the project duration for constructing many bored piles on one site is much more complicated than adding up the time duration for individual piles. In practice, project schedules are often found to be unrealistic and incorrect during the construction stage. This is because construction planning is not based on a exhaustive and comprehensive evaluation of site factors, such as site layout plan, site constraints, quality control, environmental control, safety control and logical relationships between different trades. In this paper, we identify those factors based on a foundation engineering site in Hong Kong with ninety-seven bored piles and address their effects on uncertainties in activity time and project time.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.19 no.3
• /
• pp.139-149
• /
• 1994

In many project-oriented production systems, e. g., shipyards or large-scale steel products manufacturing, resource loading by an activity is flexible, and the activity duration is a function of resource allocation. For example, if one doubles the size of the crew assigned to perform an activity, it may be feasible to complete the activity in half the duration. Such flexibility has been modeled by Weglarz [13] and by Leachman, Dincerler, and Kim [7[ in extended formulations of the resource-constrained poject scheduling problem. This paper presents a new algorithmic approach to the problem that combines the ideas proposed by the aforementioned authors. The method we propose involves a two-step approach : (1) solve the resource-constrained scheduling problem using a heuristic, and (2) using this schedule as an initial feasible solution, find improved resource allocations by solving a linear programming model. We provide computational results indicating the superiority of this approach to previous methodology for the resource-constrained scheduling problem. Extensions to the model to admit overlap relationship of the activities also are presented.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1994.04a
• /
• pp.410-420
• /
• 1994

In many project-oriented production systems, e.g., shipyards or large-scale steel products manufacturing, resource loading by an activity is flexible, and the activity duration is a function of resource allocation. For example, if one doubles the size of the crew assigned to perform an activity, it may be feasible to complete the activity in half the duration. Such flexibility has been modeled by Weglarz [131 and by Leachman, Dincerler, and Kim [7] in extended formulations of the resource-constrained project scheduling problem. This paper presents a new algorithmic approach to the problem that combines the ideas proposed by the aforementioned authors. The method we propose involves a two-step approach: (1) solve the resource-constrained scheduling problem using a heuristic, and (2) using this schedule as an initial feasible solution, find improved resource allocations by solving a linear programming model. We provide computational results indicating the superiority of this approach to previous methodology for the resource-constrained scheduling problem. Extensions to the model to admit overlap relationships of the activities also are presented.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2006.11a
• /
• pp.444-447
• /
• 2006

Construction managers need to pay a close attention to the resource utilization in order to deliver the construction project successfully. Construction scheduling is crucial for resource control in that it provides information when and how much to bring down work force to sites. In scheduling, activity duration is projected based on the productivity of historical data or the intuition of scheduler. This paper studies the opportunity of applying cost-based productivity for estimating activity duration. For cost-based productivity, the cost of resource is used as an input and the work quantities as an output. Out of historical data, regression model has been developed to understand the validity of applying cost-based productivity in projecting activity duration. The result of study will work as a prerequisite for implementing the environment of database-based construction scheduling.

• Journal of Korean Academic Society of Home Health Care Nursing
• /
• v.26 no.2
• /
• pp.180-188
• /
• 2019

Purpose: To investigate the duration of each nursing activity performed by home care nurses for non-cancer patients and the relationship between patients' palliative prognostic index (PPI) and duration of each nursing activity. Methods: Nursing activities performed for six non-cancer terminal patients were timed using a stopwatch, and 18 parameters were measured by visiting each patient thrice. The mean and standard deviations of duration for each category of nursing activities were computed. The relationship between category-specific duration of nursing activities and PPI was analyzed with Spearman's correlation and multiple regression analysis. Results: Among nursing activities, the highest greatest duration of time was spent on traffic time (11.91 min), followed by urinary catheter management (10.65 min) and insertion and management of nasogastric tube (9.03 min). In terms of nursing categories, after excluding movement time, the greatest duration of time was spent on excretion care (5.48 min), nutrition care (5.40 min), and medication (3.82 min). PPI correlated with hygiene care, excretion care, and patient and information management. Multiple regression analysis revealed that PPI increased with increasing duration of hygiene care. Conclusion: These study findings provide grounds for the increased nursing time of hygiene care for people reaching the end of life.

• Physical Therapy Korea
• /
• v.1 no.1
• /
• pp.25-34
• /
• 1994

This study investigated the hypothesis that purposeful activity is an intrinsic motivator. Affecting exertion during the performance of purposeful and nonpurposeful activity was studied in 30 elementary school students. The subjects acted as their own controls in the performance of other exercise. The three experimental exercises were jumping rope, defined as a nonpurposeful activity, and jumping rope with reinforcement, defined as purposeful activity I, and jumping rope with double reinforcement (food), defined as purposeful activity II. Duration and cessation of exercise were entirely controlled by the subject. The number of jumps were measured immediately after cessation of exercise and duration of exercise in seconds by observer. The results were as follows : 1. There was a significant difference in the required time of performance between purposeful and nonpurposeful jumping (p< .05). 2. There was a significant difference in the number of jumps between nonpurposeful and nonpurposeful jumping after reinforcement. (p< .05). Implications for practice and further research are discussed.

• Safety and Health at Work
• /
• v.10 no.3
• /
• pp.389-392
• /
• 2019

When conducting an exposure assessment, the primary goal of the industrial hygienist is to fully characterize the worker's exposure during a work shift to compare it with an occupational exposure limit. This applies regardless of the duration of the work activity as an activity that is relatively short in duration can still present exposure in excess of the occupational exposure limit even when normalized over an 8-hr shift. This goal, however, is often impeded by the specification of a minimum sample volume in the published sampling method, which may prevent the sample from being collected or submitted for analysis. Removing the specification of minimum sample volume (or adjusting it from a requirement to a recommendation), in contrast, allows for a broader assessment of jobs that consist of short-duration and high-exposure activities and also eliminates the unnecessary practice of running sampling pumps in clean air to collect a specified, minimum volume.

• The Korean Journal of Physiology and Pharmacology
• /
• v.8 no.1
• /
• pp.33-41
• /
• 2004

We developed a cardiac cell model to explain the phenomenon of mechano-electric feedback (MEF), based on the experimental data with rat atrial myocytes. It incorporated the activity of ion channels, pumps, exchangers, and changes of intracellular ion concentration. Changes in membrane excitability and $Ca^{2+}$ transients could then be calculated. In the model, the major ion channels responsible for the stretch-induced changes in electrical activity were the stretch-activated channels (SACs). The relationship between the extent of stretch and activation of SACs was formulated based on the experimental findings. Then, the effects of mechanical stretch on the electrical activity were reproduced. The shape of the action potential (AP) was significantly changed by stretch in the model simulation. The duration was decreased at initial fast phase of repolarization (AP duration at 20% repolarization level from 3.7 to 2.5 ms) and increased at late slow phase of repolarization (AP duration at 90% repolarization level from 62 to 178 ms). The resting potential was depolarized from -75 to -61 mV. This mathematical model of SACs may quantitatively predict changes in cardiomyocytes by mechanical stretch.

• Journal of International Academy of Physical Therapy Research
• /
• v.4 no.1
• /
• pp.532-538
• /
• 2013

The purpose of this study is to analyze the grip strength by the girth of upper arm and forearm and their muscle activities by duration of grip strength. The subjects were consisted of 20 healthy adults(10 males & 10 females) who had no medical history of neurological and surgical problems with their arms. Girth of upper arm/ forearm and maximum grip strength for 4sec and 30sec were measured. Muscle activity was by wireless electrode EMG system. Co-relation of girth of upper arm/ forearm was significantly high. Upper arm's muscle activity performed for 4sec and 30sec was significantly high. In this study. It suggests that training of upper arm should be performed with the training of grip strength because both of upper arm and forearm affected grip strength.

• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.4
• /
• pp.231-236
• /
• 2012

We studied the effects of acetylcholinesterase inhibitors, donepezil and galantamine, and an N-methyl-D-aspartate (NMDA) receptor blocker, memantine, on sleep-wake architecture in rats. Screw electrodes were chronically implanted into the frontal and parietal cortex for the electroencephalography (EEG). EEG was recorded with a bio-potential amplifier for 8 h from 09:30 to 17:30. Vibration was recorded to monitor animal activity with a vibration measuring device. Sleep-wake states such as wake (W), slow-wave sleep (S) and paradoxical or rapid eye movement sleep (P), were scored every 10 sec by an experimenter. We measured mean episode duration and number of episode to determine which factor sleep disturbance was attributed to. Donepezil and memantine showed a significant increase in total W duration and decreases in total S and P duration and delta activity. Memantine showed increases in sleep latency and motor activity. Changes of S and P duration in memantine were attributed from changes of mean episode duration. Galantamine had little effect on sleep architecture. From these results, it is showed that galantamine may be an anti-dementia drug that does not cause sleep disturbances and memantine may be a drug that causes severe sleep disturbance.