Sampling Methods� Evolution in Problem of Duration Reduction of Project with Limited Resources

10.12737/5782 ◽  
2014 ◽  
Vol 3 (3) ◽  
pp. 14-24
Author(s):  
������� ◽  
Igor Tsarkov
Keyword(s):  
Sampling Method ◽  
Sampling Methods ◽  
Optimization Methods ◽  
Heuristic Methods ◽  
Project Duration ◽  
Resource Conflicts ◽  
Problem Resolution ◽  
Reduction Problem ◽  
Real Practice ◽  
Exact Optimization

The project duration reduction problem in the conditions of limited renewable resources is one of the most popular themes within researches in area of project management�s mathematical models during more than 50 years. Nowadays applying of exact optimization methods in real practice is impossible, so heuristic methods are used in this problem resolution. Among a set of heuristic methods there is a considerable share of so-called multipass scheduling methods based on consecutive application of different heuristic rules of resource conflicts resolution to the same project. If at this each new schedule turns out with use of random numbers, they speak about sampling. In this paper a review of existing sampling methods will be made, and their efficiency research on the basis of PSPLIB projects will be conducted. Besides, has been received a confirmation that at a large number of iterations in a sampling method the parallel schemes surpass consecutive ones, and a new method of sampling combining various schemes and rules of priority has been constructed.

Non-Probabilistic Sampling in Quantitative Clinical Research

2022 ◽  
Vol 7 (1) ◽  
pp. 0-0
Keyword(s):  
Best Practices ◽  
Quantitative Research ◽  
Sampling Method ◽  
Sampling Methods ◽  
Early Career ◽  
Probability Sampling ◽  
Probabilistic Sampling ◽  
Quantitative Studies ◽  
Health Studies ◽  
Probabilistic Sample

Quantitative researchers need a probabilistic sample to generalise their findings, but research constraints often compel them to use non-probabilistic samples. The use of non-probability sampling methods in quantitative studies has therefore become a norm. Interestingly, even studies published in top-quality journals compromise best practices that the use of non-probabilistic samples requires. Based on a thorough review of relevant studies, we developed a typology of non-probability sampling methods used in quantitative health studies. An attempt was made to discuss the limit of inference under each type of non-probability sampling method. Non-probability sampling in quantitative research was also delineated as a way to maximise response rate. This study is expected to guide students and early career epidemiologists to understand how to apply non-probabilistic sampling methods in quantitative approaches and plausibly document or report their chosen methods.

Digital instruments for reporting of gastrointestinal symptoms in clinical trials: comparison of end-of-day diaries versus experience sampling method (Preprint)

2021 ◽  
Author(s):  
Abraham B. Beckers ◽  
Johanna T.W. Snijkers ◽  
Zsa Zsa R.M. Weerts ◽  
Lisa Vork ◽  
Tim Klaassen ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Randomized Controlled Trial ◽  
Irritable Bowel Syndrome ◽  
Sampling Method ◽  
Sampling Methods ◽  
Controlled Trial ◽  
Smartphone Application ◽  
Randomized Controlled ◽  
Pre Treatment ◽  
Irritable Bowel

BACKGROUND Questionnaires are necessary tools for assessing symptoms of disorders of the brain-gut interaction in clinical trials. We previously reported on the excellent compliance to a smartphone app used as symptom diary in a randomized clinical trial in irritable bowel syndrome (IBS). Other sampling methods, such as the experience sampling method (ESM), are better equipped to measure symptom variability over time, provide useful information regarding possible symptom triggers and are free of ecological and recall bias. The high frequency of measurements, however, could limit the feasibility of ESM in clinical trials. OBJECTIVE This study aimed to compare compliance rates of a smartphone-based end-of-day diary and ESM for symptom assessment in irritable bowel syndrome and functional dyspepsia (FD). METHODS Data from four studies were included. Patients with IBS participated in a randomized controlled trial, which involved a smartphone end-of-day diary of 2+8 weeks (pre-treatment + treatment period), and an observational study, during which patients completed ESM assessments using a smartphone application for one week. Patients with FD participated in a randomized controlled trial, which involved a smartphone end-of-day diary of 2+12 weeks (pre-treatment + treatment period), and an observational study, during which patients completed ESM assessments using a smartphone application for one week. Compliance rates were compared between these two symptom sampling methods. RESULTS Twenty-five patients with IBS and fifteen patients with FD were included. Overall compliance rates for the end-of-day diaries were significantly higher than for ESM (IBS: 92.7% versus 69.8%, FD: 90.1% versus 61.4%, respectively). CONCLUSIONS We here demonstrate excellent compliance rates for smartphone application-based end-of-day diaries as used in two separate clinical trials. Overall compliance rates for ESM were significantly lower, rendering it more suitable for intermittent sampling periods rather than continuously during longer clinical trials.

Sampling Methods and Frozen Storage of Samples for Detection of Campylobacter jejuni on Freshly Processed Broiler Carcasses

1983 ◽  
Vol 46 (6) ◽  
pp. 510-513 ◽  
Author(s):  
L. C. BLANKENSHIP ◽  
S. E. CRAVEN ◽  
J. Y. CHIU ◽  
G. W. KRUMM
Keyword(s):  
Campylobacter Jejuni ◽  
Sampling Method ◽  
Sampling Methods ◽  
Frozen Storage ◽  
Test Tube ◽  
Tissue Samples ◽  
Defibrinated Sheep Blood ◽  
Cryoprotective Agents ◽  
Plastic Bags ◽  
Sampling Locations

Swab, rinse and excision sampling methods are commonly used for detection of microorganisms on poultry carcasses. Swabbing has been the most frequently reported sampling method for Campylobacter jejuni on poultry. We evaluated the three methods for C. jejuni detection on freshly processed poultry in the following ways: (a) the interior and exterior surfaces of half of a carcass were each thoroughly rubbed with separate swabs which were combined in a test tube containing 2 ml of appropriate medium; (b) 25 g of skin and tissue samples from neck and abdominal opening cut areas were deposited in a stomacher bag with 5 ml of brucella broth (BB) and stomached for 2 min; and (c) half carcasses were shaken for 1 min with 100 ml BB in plastic bags. One drop of each sample was streaked for isolation on brucella agar containing 10% defibrinated sheep blood and Skirrow antibiotics. Isolates were identified by microscopy and appropriate cultural tests. All three sampling techniques were essentially equivalent for detection of C. jejuni on fresh carcasses. However, when samples were stored frozen for 7 to 10 d to simulate transport conditions from sampling locations to the laboratory, the incidence of detection was significantly reduced. Use of cryoprotective agents was an effective method to preserve swab samples during frozen storage.

Participative Management of Employees in Decision-Making: An Empirical Study

2018 ◽  
Vol 2 (2) ◽  
pp. 1-5
Author(s):  
B. Ravi Kumar
Keyword(s):  
Decision Making ◽  
Empirical Study ◽  
Sampling Method ◽  
Sampling Methods ◽  
Steel Plant ◽  
Participative Management ◽  
Decision Making Process ◽  
Labour Policy

Participative management of employees in decision-making is considered as a mechanism where workers have a say in the decision making process of an organization. In India WPM is an element of government labour policy. The concept behind this is to improve better relations among employees and workers. The present paper tries to explore about the workers participation in management in Visakhapatnam Steel Plant (VSP) by considering 604 respondent employees of steel plant in order to know their opinions regarding the above mentioned topics by using convenient sampling method, because VSP is big organization consisting of more than 20,000 employees (Both Permanent and Contract). All the employees are busy at their work and it will be difficult to collect the first hand information from the employees by using any other sampling methods except convenient sampling method.

Body Measurement of Reared Red Sea Bream Using Stereo Vision

2018 ◽  
Vol 30 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Kazuyoshi Komeyama ◽  
Tatsuya Tanaka ◽  
Takeharu Yamaguchi ◽  
Shigeru Asaumi ◽  
Shinsuke Torisawa ◽  
...  
Keyword(s):  
Red Sea ◽  
Stereo Vision ◽  
Sampling Method ◽  
Sampling Methods ◽  
Vision System ◽  
Fork Length ◽  
Sea Bream ◽  
Physical Injury ◽  
Red Sea Bream ◽  
Aquaculture Management

For aquaculture management, aquaculture farmers require a new, inexpensive device that can obtain the size of a fish without touching them, replacing the conventional spoon-net sampling method. Conventional sampling involves the risks of physical injury and mental stress to the fish, which may affect their growth rate and mortality. Therefore, we developed methods for monitoring the size of fish, considering red sea bream (RSB) aquaculture, using commercially available cameras. This study evaluates the sample size using the estimated mean fork length value in a cage, and its value is approximately 20 samples with a 2% error rate for a fork length of greater than 30 cm. We measured the fish fork length under water in the cage using both stereo vision and net-sampling methods simultaneously. The examination demonstrated that for RSB aquaculture, the estimated values of fork length from the two methods have no statistical difference. This result implies that our stereo vision system can be effectively applied to monitor RSB growth.

The Effect of Sampling on the Undrained Soil Properties of a Leda Soil

1971 ◽  
Vol 8 (4) ◽  
pp. 546-557 ◽  
Author(s):  
Gerald P. Raymond ◽  
David L. Townsend ◽  
Miroslav J Lojkasek
Keyword(s):  
Sampling Method ◽  
Sampling Methods ◽  
Axial Stress ◽  
Pressure Coefficient ◽  
Confining Pressure ◽  
Stress Difference ◽  
Consolidation Pressure ◽  
Failure Index ◽  
Confining Pressures ◽  
Leda Clay

The comparison of consolidated undrained triaxial results on sensitive Leda clay sampled by six different sampling methods is presented. The results indicate that the failure index, represented by the axial stress difference as a fraction of the axial failure stress difference against strain plots, are widely different at very low consolidation pressures, but are similar and approximate to the results from block samples as the consolidation pressure is increased. The pore pressure coefficient A appears to be independent of the sampling method and remains remarkably consistent throughout any test (up to failure) except where the confining pressure is very low or above the preconsolidation pressure.Routine commercial sampling methods (including laboratory preparation) using 50-mm diameter samples were found to partially destroy the cementation bonds, causing a decrease in strength at low confining pressures and an unsafe increase in strength at medium confining pressures. This trend is decreased by better sampling.

Evaluation of sampling methods for monitoring effluent phosphorus for on-site wastewater treatment systems

2012 ◽  
Vol 65 (11) ◽  
pp. 2049-2054 ◽  
Author(s):  
Erik Johannessen ◽  
Arild Schanke Eikum ◽  
Tore Krogstad
Keyword(s):  
Wastewater Treatment ◽  
Sampling Method ◽  
Sampling Methods ◽  
Wastewater Treatment Plants ◽  
Monitoring Program ◽  
Grab Sampling ◽  
Significant Difference ◽  
Student’S T ◽  
Composite Samples ◽  
Student’S T Test

More than 1,600 prefabricated on-site wastewater treatment plants are in operation in the Morsa watershed in Norway. As of 2010 a monitoring program on the performance of these plants is in effect. Sampling methods for wastewater treatment plants is discussed, and different methods are compared. The study includes six different plant models, of which all are prefabricated package plants. The parameters investigated were total phosphorus (Tot-P), orthophosphate (PO4-P) and suspended solids (SS). Diurnal curves showed no apparent repetitive variation over 24 h intervals, indicating good equalization and robust design to compensate for highly variable loadings. A comparison of grab samples and time proportional composite samples showed almost identical average values, and a paired two-tailed Student's t-test indicates no statistically significant difference between the sampling methods. The results indicate that equivalent results should be expected irrespective of sampling method, and, as composite sampling is attributed to much higher costs, it is recommended that grab sampling should be used when a large number of plants are evaluated.

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