Scheduling Unit Jobs with a Common Deadline to Minimize the Sum of Weighted Completion Times and Rejection Penalties

2014 ◽  
pp. 646-657 ◽  
Author(s):  
Nevzat Onur Domaniç ◽  
C. Gregory Plaxton
Keyword(s):  
Completion Times

Penjadwalan Mesin dengan Metode Integer Linear Programming pada PT. XYZ

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Fransiskus Lauson Matondang ◽  
Rosnani Ginting
Keyword(s):  
Integer Programming ◽  
Time Delays ◽  
Parallel Machines ◽  
Research Concept ◽  
Total Settlement ◽  
Approach Method ◽  
Additional Costs ◽  
Maximum Completion Time ◽  
Completion Times ◽  
Better Than

PT XYZ sering mengalami keterlambatan waktu karena dalam setiap keterlambatan yang dilakukan selalu ada penalty yang diberikan kepada perusahaan dan hal ini mengakibatkan tambahan biaya , oleh karena itu hal ini harus dihindari dengan membuat penjadwalan yang efisien, dalam hal ini dilakukanlah perbaikan dengan meminimisasi waktu penyelesaian maksimum Cmax pada mesin paralel yang berpola aliran flowshop (dan tidak boleh dilakukan interupsi yang dilakukan pada pekerjaan yang sedang diproses, untuk melakukan pekerjaan lainnya, satu lintasan hanya memproduksi satu produk dan hanya satu produk juga yang dikerjakan secara langsung. Waktu penyelesaian yang berbeda dari setiap mesin dengan pengerjaannya juga adalah masalah yang dihadapi untuk menjadikan mesin mesin ini sesuai menjadi satu penjadwalan yang terintegrasi dengan metode integer programming yang membuat penjadwalan dengan konsep riset operasi dengan metode pendekatan 0-1 utuk menjadi lebih efisien lagi , dihasilkan minimisasi keterlambatan total penyelesaian order dengan 42,28 menit lebih baik dari sebelumnya.   PT XYZ often experiences time delays because in every delay made there is always a penalty given to the company and this results in additional costs, therefore this must be avoided by making efficient scheduling, in this case repairs are carried out by minimizing the maximum completion time of Cmax on parallel machines that are patterned with flowshop flow (and no interruptions should be carried out on the work being processed, to do other work, one track only produces one product and only one product is directly worked. Different completion times of each machine with the workmanship is also the problem faced to make this machine suitable to be one scheduling integrated with integer programming methods that makes scheduling with the operational research concept with the 0-1 approach method to be more efficient, resulting in minimization of the delay in the total settlement of orders with 42.28 minutes was better than before.

scholarly journals Investigation of spatial ability test completion times in virtual reality using a desktop display and the Gear VR

2021 ◽  
Author(s):  
Tibor Guzsvinecz ◽  
Éva Orbán-Mihálykó ◽  
Cecília Sik-Lányi ◽  
Erika Perge
Keyword(s):  
Virtual Reality ◽  
Mental Rotation ◽  
Spatial Ability ◽  
Interaction Time ◽  
Ability Test ◽  
Ability Tests ◽  
Hand Test ◽  
The Relationship ◽  
Completion Times ◽  
Test Completion

AbstractThe interaction time of students who did spatial ability tests in a virtual reality environment is analyzed. The spatial ability test completion times of 240 and 61 students were measured. A desktop display as well as the Gear VR were used by the former group and by the latter one, respectively. Logistic regression analysis was used to investigate the relationship between the probability of correct answers and completion times, while linear regression was used to evaluate effects and interactions of following factors on test completion times: the users’ gender and primary hand, test type and device used. The findings were that while the completion times are not significantly affected by the users’ primary hand, other factors have significant effects on them: they are decreased by the male gender in itself, while they are increased by solving Mental Rotation Tests or by using the Gear VR. The largest significant increment in interaction time in virtual reality during spatial ability tests is when Mental Rotation Tests are accomplished by males with the Gear VR, while the largest significant decrease in interaction time is when Mental Cutting Tests are completed with a desktop display.

scholarly journals Repeatability, Completion Time, and Predictive Ability of Four Diabetes-Related Foot Ulcer Classification Systems

2021 ◽  
pp. 193229682098654
Author(s):  
Chanika Alahakoon ◽  
Malindu Fernando ◽  
Charith Galappaththy ◽  
Peter Lazzarini ◽  
Joseph V. Moxon ◽  
...  
Keyword(s):  
Foot Ulcer ◽  
Predictive Ability ◽  
Classification Systems ◽  
The Other ◽  
Observer Agreement ◽  
Foot Ulcers ◽  
Substantial Agreement ◽  
University Of Texas ◽  
Trained Observers ◽  
Completion Times

Introduction: The inter and intra-observer reproducibility of measuring the Wound Ischemia foot Infection (WIfI) score is unknown. The aims of this study were to compare the reproducibility, completion times and ability to predict 30-day amputation of the WIfI, University of Texas Wound Classification System (UTWCS), Site, Ischemia, Neuropathy, Bacterial Infection and Depth (SINBAD) and Wagner classifications systems using photographs of diabetes-related foot ulcers. Methods: Three trained observers independently scored the diabetes-related foot ulcers of 45 participants on two separate occasions using photographs. The inter- and intra-observer reproducibility were calculated using Krippendorff’s α. The completion times were compared with Kruskal-Wallis and Dunn’s post-hoc tests. The ability of the scores to predict 30-day amputation rates were assessed using receiver operator characteristic curves and area under the curves. Results: There was excellent intra-observer agreement (α >0.900) and substantial agreement between observers (α=0.788) in WIfI scoring. There was moderate, substantial, or excellent agreement within the three observers (α>0.599 in all instances except one) and fair or moderate agreement between observers (α of UTWCS=0.306, α of SINBAD=0.516, α of Wagner=0.374) for the other three classification systems. The WIfI score took significantly longer ( P<.001) to complete compared to the other three scores (medians and inter quartile ranges of the WIfI, UTWCS, SINBAD, and Wagner being 1.00 [0.88-1.00], 0.75 [0.50-0.75], 0.50 [0.50-0.50], and 0.25 [0.25-0.50] minutes). None of the classifications were predictive of 30-day amputation ( P>.05 in all instances). Conclusion: The WIfI score can be completed with substantial agreement between trained observers but was not predictive of 30-day amputation.

scholarly journals Analysing Touchscreen Gestures: A Study Based on Individuals with Down Syndrome Centred on Design for All

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1328
Author(s):  
Jorge Martin-Gutierrez ◽  
Marta Sylvia Del Rio Guerra
Keyword(s):  
Socioeconomic Status ◽  
Down Syndrome ◽  
Cognitive Impairments ◽  
Pairwise Comparison ◽  
Success Rates ◽  
Touch Gestures ◽  
Design For All ◽  
Significant Difference ◽  
Collateral Effect ◽  
Completion Times

There has been a conscious shift towards developing increasingly inclusive applications. However, despite this fact, most research has focused on supporting those with visual or hearing impairments and less attention has been paid to cognitive impairments. The purpose of this study is to analyse touch gestures used for touchscreens and identify which gestures are suitable for individuals living with Down syndrome (DS) or other forms of physical or cognitive impairments. With this information, app developers can satisfy Design for All (DfA) requirements by selecting adequate gestures from existing lists of gesture sets. Twenty touch gestures were defined for this study and a sample group containing eighteen individuals with Down syndrome was used. A tool was developed to measure the performance of touch gestures and participants were asked to perform simple tasks that involved the repeated use of these twenty gestures. Three variables are analysed to establish whether they influence the success rates or completion times of gestures, as they could have a collateral effect on the skill with which gestures are performed. These variables are Gender, Type of Down syndrome, and Socioeconomic Status. Analysis reveals that significant difference is present when a pairwise comparison is performed, meaning individuals with DS cannot perform all gestures with the same ease. The variables Gender and Socioeconomic Status do not influence success rates or completion times, but Type of DS does.

scholarly journals Online Makespan Scheduling with Job Migration on Uniform Machines

Algorithmica ◽  
2021 ◽  
Author(s):  
Matthias Englert ◽  
David Mezlaf ◽  
Matthias Westermann
Keyword(s):  
Competitive Ratio ◽  
Online Algorithm ◽  
Parallel Machines ◽  
Scheduling Algorithm ◽  
Input Sequence ◽  
Job Migration ◽  
Average Completion Time ◽  
Uniform Machine ◽  
Uniform Machines ◽  
Completion Times

AbstractIn the classic minimum makespan scheduling problem, we are given an input sequence of n jobs with sizes. A scheduling algorithm has to assign the jobs to m parallel machines. The objective is to minimize the makespan, which is the time it takes until all jobs are processed. In this paper, we consider online scheduling algorithms without preemption. However, we allow the online algorithm to change the assignment of up to k jobs at the end for some limited number k. For m identical machines, Albers and Hellwig (Algorithmica 79(2):598–623, 2017) give tight bounds on the competitive ratio in this model. The precise ratio depends on, and increases with, m. It lies between 4/3 and $$\approx 1.4659$$ ≈ 1.4659 . They show that $$k = O(m)$$ k = O ( m ) is sufficient to achieve this bound and no $$k = o(n)$$ k = o ( n ) can result in a better bound. We study m uniform machines, i.e., machines with different speeds, and show that this setting is strictly harder. For sufficiently large m, there is a $$\delta = \varTheta (1)$$ δ = Θ ( 1 ) such that, for m machines with only two different machine speeds, no online algorithm can achieve a competitive ratio of less than $$1.4659 + \delta $$ 1.4659 + δ with $$k = o(n)$$ k = o ( n ) . We present a new algorithm for the uniform machine setting. Depending on the speeds of the machines, our scheduling algorithm achieves a competitive ratio that lies between 4/3 and $$\approx 1.7992$$ ≈ 1.7992 with $$k = O(m)$$ k = O ( m ) . We also show that $$k = \varOmega (m)$$ k = Ω ( m ) is necessary to achieve a competitive ratio below 2. Our algorithm is based on maintaining a specific imbalance with respect to the completion times of the machines, complemented by a bicriteria approximation algorithm that minimizes the makespan and maximizes the average completion time for certain sets of machines.

scholarly journals Minimizing the sum of weighted completion times in a concurrent open shop

2010 ◽  
Vol 38 (5) ◽  
pp. 390-395 ◽  
Author(s):  
Monaldo Mastrolilli ◽  
Maurice Queyranne ◽  
Andreas S. Schulz ◽  
Ola Svensson ◽  
Nelson A. Uhan
Keyword(s):  
Open Shop ◽  
Completion Times
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