scholarly journals Mathematical models and a constructive heuristic for finding minimum fundamental cycle bases

2005 ◽  
Vol 15 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Leo Liberti ◽  
Edoardo Amaldi ◽  
Francesco Maffioli ◽  
Nelson Maculan
Keyword(s):  
Linear Programming ◽  
Total Cost ◽  
Fundamental Cycle ◽  
Cycle Basis ◽  
Cpu Time ◽  
Constructive Heuristic ◽  
Cycle Bases ◽  
Time Required ◽  
Application Fields

The problem of finding a fundamental cycle basis with minimum total cost in a graph arises in many application fields. In this paper we present some integer linear programming formulations and we compare their performances, in terms of instance size, CPU time required for the solution, and quality of the associated lower bound derived by solving the corresponding continuous relaxations. Since only very small instances can be solved to optimality with these formulations and very large instances occur in a number of applications, we present a new constructive heuristic and compare it with alternative heuristics.

EXPERIMENTAL ANALYSIS OF SOME VARIANTS OF VOGEL'S APPROXIMATION METHOD

2004 ◽  
Vol 21 (04) ◽  
pp. 447-462 ◽  
Author(s):  
M. MATHIRAJAN ◽  
B. MEENAKSHI
Keyword(s):  
Approximation Method ◽  
Opportunity Cost ◽  
Optimal Solution ◽  
Efficient Solutions ◽  
Transportation Problems ◽  
Cpu Time ◽  
Problem Instances ◽  
Time Required ◽  
The Military

This paper presents a variant of Vogel's approximation method (VAM) for transportation problems. The importance of determining efficient solutions for large sized transportation problems is borne out by many practical problems in industries, the military, etc. With this motivation, a few variants of VAM incorporating the total opportunity cost (TOC) concept were investigated to obtain fast and efficient solutions. Computational experiments were carried out to evaluate these variants of VAM. The quality of solutions indicates that the basic version of the VAM coupled with total opportunity cost (called the VAM–TOC) yields a very efficient initial solution. In these experiments, on an average, about 20% of the time the VAM–TOC approach yielded the optimal solution and about 80% of the time it yielded a solution very close to optimal (0.5% loss of optimality). The CPU time required for the problem instances tested was very small (on an average, less than 10 s on a 200 MHz Pentium machine with 64 MB RAM).

Reduced influence of affective disorders on perioperative complication rates, length of hospital stay, and healthcare costs following spinal fusion for adolescent idiopathic scoliosis

2019 ◽  
Vol 24 (6) ◽  
pp. 722-727
Author(s):  
Aladine A. Elsamadicy ◽  
Andrew B. Koo ◽  
Megan Lee ◽  
Adam J. Kundishora ◽  
Christopher S. Hong ◽  
...  
Keyword(s):  
Quality Of Care ◽  
Idiopathic Scoliosis ◽  
Affective Disorder ◽  
Affective Disorders ◽  
Complication Rates ◽  
Total Cost ◽  
Adolescent Patients ◽  
Perioperative Complication ◽  
The Impact

OBJECTIVEIn the past decade, a gradual transition of health policy to value-based healthcare has brought increased attention to measuring the quality of care delivered. In spine surgery, adolescents with scoliosis are a population particularly at risk for depression, anxious feelings, and impaired quality of life related to back pain and cosmetic appearance of the deformity. With the rising prevalence of mental health ailments, it is necessary to evaluate the impact of concurrent affective disorders on patient care after spinal surgery in adolescents. The aim of this study was to investigate the impact that affective disorders have on perioperative complication rates, length of stay (LOS), and total costs in adolescents undergoing elective posterior spinal fusion (PSF) (≥ 4 levels) for idiopathic scoliosis.METHODSA retrospective study of the Kids’ Inpatient Database for the year 2012 was performed. Adolescent patients (age range 10–17 years old) with AIS undergoing elective PSF (≥ 4 levels) were selected using the International Classification of Diseases, Ninth Revision, Clinical Modification coding system. Patients were categorized into 2 groups at discharge: affective disorder or no affective disorder. Patient demographics, comorbidities, complications, LOS, discharge disposition, and total cost were assessed. The primary outcomes were perioperative complication rates, LOS, total cost, and discharge dispositions.RESULTSThere were 3759 adolescents included in this study, of whom 164 (4.4%) were identified with an affective disorder (no affective disorder: n = 3595). Adolescents with affective disorders were significantly older than adolescents with no affective disorders (affective disorder: 14.4 ± 1.9 years vs no affective disorder: 13.9 ± 1.8 years, p = 0.001), and had significantly different proportions of race (p = 0.005). Aside from hospital region (p = 0.016), no other patient- or hospital-level factors differed between the cohorts. Patient comorbidities did not differ significantly between cohorts. The number of vertebral levels involved was similar between the cohorts, with the majority of patients having 9 or more levels involved (affective disorder: 76.8% vs no affective disorder: 79.5%, p = 0.403). Postoperative complications were similar between the cohorts, with no significant difference in the proportion of patients experiencing a postoperative complication (p = 0.079) or number of complications (p = 0.124). The mean length of stay and mean total cost were similar between the cohorts. Moreover, the routine and nonroutine discharge dispositions were also similar between the cohorts, with the majority of patients having routine discharges (affective disorder: 93.9% vs no affective disorder: 94.9%, p = 0.591).CONCLUSIONSThis study suggests that affective disorders may not have a significant impact on surgical outcomes in adolescent patients undergoing surgery for scoliosis in comparison with adults. Further studies are necessary to elucidate how affective disorders affect adolescent patients with idiopathic scoliosis, which may improve provider approach in managing these patients perioperatively and at follow-up in hopes to better the overall patient satisfaction and quality of care delivered.

Heat Transfer Enhancement in Separation Process of Ethanol from Ethanol Water Mixture by Using Surfactants

2020 ◽  
pp. 9-14 ◽  
Author(s):  
Acharya Anil Ramchandra ◽  
R. Kadam ◽  
A. T. Pise
Keyword(s):  
Heat Transfer ◽  
Ammonium Chloride ◽  
Sodium Dodecyl ◽  
Water Mixture ◽  
Transfer Enhancement ◽  
Surface Tension Reduction ◽  
Surface Active Agents ◽  
Surface Active ◽  
Time Required

Here the investigations are done while distillation of ethanol-water mixture for separating ethanol from fermentation process. Focus is to study reduction in time required and hence saving in energy for the distillation process of ethanol-water mixture under the influence of surface-active agents (Surfactants). This novelty is from observation of these surfactants to enhance heat transfer rate because of surface tension reduction in aqueous solutions. SDS (Sodium Dodecyl Sulphate), NH4Cl (Ammonium Chloride) and SLBS (Sodium lauryl benzene sulphonate) surfactants in different concentration are experimented. The concentration of these surfactant is varied from 1700 ppm to 2800 ppm. This range is decided by observing critical micelle concentration of used surfactants. Results showed that time is reduced and hence energy consumption is also reduced. Results shown by NH4Cl are found to be more useful as it is ecofriendly surfactant which is not affecting ethanol-water mixture. Use of ammonium chloride as surfactant in distillation is actually useful to reduce energy without hampering the quality of process is the novelty of this work.

scholarly journals Multi-Task Optimization and Multi-Task Evolutionary Computation in the Past Five Years: A Brief Review

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 864
Author(s):  
Qingzheng Xu ◽  
Na Wang ◽  
Lei Wang ◽  
Wei Li ◽  
Qian Sun
Keyword(s):  
Evolutionary Computation ◽  
Explicit Knowledge ◽  
Optimization Problems ◽  
Effective Means ◽  
Typical Application ◽  
The Past ◽  
Current State ◽  
Evolution Algorithms ◽  
Application Fields

Traditional evolution algorithms tend to start the search from scratch. However, real-world problems seldom exist in isolation and humans effectively manage and execute multiple tasks at the same time. Inspired by this concept, the paradigm of multi-task evolutionary computation (MTEC) has recently emerged as an effective means of facilitating implicit or explicit knowledge transfer across optimization tasks, thereby potentially accelerating convergence and improving the quality of solutions for multi-task optimization problems. An increasing number of works have thus been proposed since 2016. The authors collect the abundant specialized literature related to this novel optimization paradigm that was published in the past five years. The quantity of papers, the nationality of authors, and the important professional publications are analyzed by a statistical method. As a survey on state-of-the-art of research on this topic, this review article covers basic concepts, theoretical foundation, basic implementation approaches of MTEC, related extension issues of MTEC, and typical application fields in science and engineering. In particular, several approaches of chromosome encoding and decoding, intro-population reproduction, inter-population reproduction, and evaluation and selection are reviewed when developing an effective MTEC algorithm. A number of open challenges to date, along with promising directions that can be undertaken to help move it forward in the future, are also discussed according to the current state. The principal purpose is to provide a comprehensive review and examination of MTEC for researchers in this community, as well as promote more practitioners working in the related fields to be involved in this fascinating territory.

scholarly journals Public Awareness and Disaster Risk Reduction: Just-in-Time Networks and Learning

2008 ◽  
Vol 23 (3) ◽  
pp. 286-288 ◽  
Author(s):  
Ali Ardalan ◽  
Faina Linkov ◽  
Eugene Shubnikov ◽  
Ronald E. LaPorte
Keyword(s):  
Hurricane Katrina ◽  
Wide Spectrum ◽  
Public Awareness ◽  
Just In Time ◽  
Educational Levels ◽  
Hazard And Risk ◽  
Time Required ◽  
Expert Network ◽  
Core Materials

AbstractImproving public awareness through education has been recognized widely as a basis for reducing the risk of disasters. Some of the first disaster just-in-time (JIT) education modules were built within 3–6 days after the south Asia tsunami, Hurricane Katrina, and the Bam, Pakistan, and Indonesia earthquakes through a Supercourse. Web monitoring showed that visitors represented a wide spectrum of disciplines and educational levels from 120 developed and developing countries. Building disaster networks using an educational strategy seizes the opportunity of increased public interest to teach and find national and global expertise in hazard and risk information. To be effective, an expert network and a template for the delivery of JIT education must be prepared before an event occurs, focusing on developing core materials that could be customized rapidly, and then be based on the information received from a recent disaster. The recyclable process of the materials would help to improve the quality of the teaching, and decrease the time required for preparation. The core materials can be prepared for disasters resulting from events such as earthquakes, hurricanes, tsunamis, floods, and bioterrorism.

Development of laboratory x-ray fluorescence holography equipment

2003 ◽  
Vol 18 (6) ◽  
pp. 1471-1473 ◽  
Author(s):  
Yukio Takahashi ◽  
Kouichi Hayashi ◽  
Kimio Wakoh ◽  
Naomi Nishiki ◽  
Eiichiro Matsubara
Keyword(s):  
Single Crystal ◽  
Count Rate ◽  
Detection System ◽  
High Count ◽  
Synchrotron Source ◽  
High Count Rate ◽  
X Ray ◽  
Graphite Monochromator ◽  
Time Required

Laboratory x-ray fluorescence holography equipment was developed. A single-bent graphite monochromator with a large curvature and a high-count-rate x-ray detection system were applied in this equipment. To evaluate the performance of this equipment, a hologram pattern of a gold single crystal was measured. It took two days, which was about one-third the time required for the previous measurements using the conventional x-ray source and several times that using the synchrotron source. The quality of the hologram pattern is as good as that obtained using the synchrotrons. Clear atomic images on (002) are reconstructed.

scholarly journals Dynamic lot sizing problem under uncertainty of returned products in remanufacturing industry

2018 ◽  
Vol 204 ◽  
pp. 07005
Author(s):  
Iman Setyoaji
Keyword(s):  
Bayesian Inference ◽  
Lot Sizing ◽  
Replacement Ratio ◽  
Total Cost ◽  
Lot Sizing Problem ◽  
Holding Cost ◽  
Dynamic Lot Sizing ◽  
Lot Sizes

Remanufacturing processes face uncertainty in the quality of the items being returned by customers, this significant variability complicates the control of inventories. Demands can be satisfied by procured new items, but also by remanufactured returned items. This paper develops dynamic lot sizing model for remanufacturing industry under uncertainty of returned items and proposes Bayesian Inference to estimate the replacement ratio of returned items that used to determine those lot sizes for new items. The objective of this paper is to minimize the total cost composed of holding cost and set-ups cost. A numerical example is provided based on case study. The result shows that total cost is reduced to be 45%.

scholarly journals IPG as a new method to improve the agility of the initial analysis of the inventive design

2021 ◽  
Vol 49 (3) ◽  
pp. 549-562
Author(s):  
Masih Hanifi ◽  
Hicham Chibane ◽  
Rémy Houssin ◽  
Denis Cavallucci
Keyword(s):  
Inverse Problem ◽  
Design Method ◽  
New Method ◽  
Significant Progress ◽  
Initial Analysis ◽  
The Subject ◽  
Time Required

TRIZ method has long proven its value without appearing to the industrial world as inevitable. Design researchers have therefore addressed the limitations of the TRIZ method and have overcome them with more systematic approaches. Among these, the Inventive Design Method (IDM) has been the subject of several articles and put into practice in the industry. It is considered an improvement over TRIZ but still suffers from some drawbacks in terms of the time-consuming nature of its implementation. We focused on the IDM process by trying to both identify its areas of inefficiencies while attempting to preserve the quality of its deliverables. Our approach consists of applying the precepts of Lean to IDM. The result is the Inverse Problem Graph (IPG) method, inspired by IDM, but offering significant progress in reducing the time required to mobilize experts while preserving its inventive outcomes. This article outlines our approach for the construction of this new method.

scholarly journals Pembuatan dan Pengujian Mesin Pemotong Lidi Tusuk Sate

2019 ◽  
Vol 4 (4) ◽  
pp. 421-430
Author(s):  
Gusri Akhyar Ibrahim ◽  
Arinal Hamni ◽  
Wahyu Budiono
Keyword(s):  
Cutting Machine ◽  
Simple Tool ◽  
Business Opportunities ◽  
The Difference ◽  
Time Required ◽  
At Home

MAKING AND TESTING OF SKEWERS CUTTING MACHINES. In Indonesia there are more than 100 types of bamboo that can be used by craftsmen, one of which is skewers. Skewers are promising commodities for business opportunities. The process of producing skewers are started from cutting down the bamboo, cutting bamboo, splitting bamboo, shriveling bamboo to become a stick skewer after that is done cutting the skewer sticks, drying sticks, polishing the sticks skewers and chopping sticks. The process of cutting a stick skewer which is done at this time is still using a simple tool, so the results are bad and the cutting time is very long. To maintain the quality of the results of a good stick skewer sticks and to increase the productivity of the stick skewers, the process of producing and testing of a skewer stick cutting machine is done. The method to produce a skewer stick cutting machine is done by designing the tool, determining the material to be used then making it. This skewer stick cutting machine is made with a press system and vertical cutting directions. From the results of testing the skewer stick cutting machine obtained that the quality of skewer cutting is good and the time required to cut is only 10 seconds. the difference is about 50 seconds faster than the hand saws used, so as to increase the productivity of the skewer sticks. The cutting machine was impelemented at home industry at Sidomulyo of South Lampung. Using the machine has increased productity and also quality of skewers.

scholarly journals Contribution to Improving the Quality of Traffic in Mobile Networks

2020 ◽  
pp. 21-28
Author(s):  
Onyonkiton Théophile Aballo ◽  
Roland Déguénonvo ◽  
Antoine Vianou
Keyword(s):  
Mobile Networks ◽  
Traffic Congestion ◽  
Loss Rate ◽  
Fourth Generation ◽  
Good Decision ◽  
Latency Jitter ◽  
Congestion Problems ◽  
Time Required ◽  
Effective Speed

Today, mobile networks are faced with congestion which results in regular slowness given the variation in the actual speed of the network, that is to say the time required to transmit all of the data from a point to another. In third and fourth generation mobile networks, actual throughput is not directly measurable, it actually consists of three separate indicators, latency, jitter and loss rate. Many studies have shown that these parameters have a particular influence on congestion problems. In practice, the effective speed on the network is inversely proportional to the latency. However, the bit rate is four times the latency. Next, jitter is the variation of latency over time, impacting the flow by influencing latency. In this article, we have examined the analysis of traffic congestion in third and fourth generation networks in order to make a comparative study of the congestion rate for good decision-making.

Sign in / Sign up

Export Citation Format

Share Document