scholarly journals METHOD OF REDUCING ORGANIZATIONAL DOWNTIME OF EQUIPMENT WHEN CHANGING THE PRODUCT RANGE

2020 ◽  
Vol 1 (30(57)) ◽  
pp. 43-48
Author(s):  
A.V. Soshnikov
Keyword(s):  
Heuristic Method ◽  
Total Duration ◽  
Combinatorial Problem ◽  
Oriented Graph ◽  
Operational Mode ◽  
Product Range ◽  
Different Types ◽  
A Chain ◽  
Production Conditions ◽  
Production Situation

The problem of reducing unproductive time losses in diversified industries associated with the need for equipment changeovers when changing the product range is considered. A model of a typical production situation is developed in the form of a combinatorial problem of finding a chain in a complete oriented graph. A heuristic method for solving the problem using a number of techniques that can significantly reduce the amount of search in the search for an acceptable criterion for the total duration of changeovers version of the order of processing of different types of products. Examples are given confirming the possibility of applying the method to solve this type of problems in production conditions in the operational mode.

Creep on the San Andreas fault

1960 ◽  
Vol 50 (3) ◽  
pp. 389-415
Author(s):  
Karl V. Steinbrugge ◽  
Edwin G. Zacher ◽  
Don Tocher ◽  
C. A. Whitten ◽  
C. N. Claire
Keyword(s):  
Creep Rate ◽  
San Andreas Fault ◽  
Total Duration ◽  
Fault Line ◽  
Fault Movement ◽  
Central California ◽  
San Andreas ◽  
Different Types ◽  
Present Rate ◽  
Local Earthquake

ABSTRACT Progressive destruction of buildings and other works of man at the W. A. Taylor Winery near Hollister, California, indicates that one side of a segment of the San Andreas fault is creeping relative to the other. Three different types of measurements all yield an annual rate of creep of approximately one-half inch per year. Steinbrugge and Zacher: Measurements of the separations of pairs of reference marks adjacent to the line of creep have been repeated periodically since 1956, and damage to structures provides a good measure of the total creep since 1948. Reports of damage to older buildings on the same site suggest that the creep may have been going on at about the present rate for fifty or more years. Tocher: Creep recorders designed to measure continuously the differential lateral movement of adjacent sections of the concrete floor have been installed in the main winery building. The creep rate so determined has been about one-half inch per year (with right-lateral sense) for the past two years. Creep accumulates largely in spasms of rather short duration (on the order of a week) separated by intervals of weeks or months during which little or no creep takes place. Ninety-two per cent of the movement in a recent 371-day period accumulated in four spasms of total duration 34 days. Three of these spasms began at times when no local earthquakes were recorded on near-by seismographs; the fourth began with a sudden right-lateral fault movement of 3 mm. at the time of a sharp local earthquake (Richter magnitude 5.0) on January 20, 1960 (GCT). Whitten and Claire: Resurveys over monumented points established near the winery also yield a rate of slippage or creep along the fault line of one-half inch per year. A new method for analyzing the data obtained by retriangulating over monumented points at wide intervals (10 to 20 years) is presented and applied to two triangulation networks which cross the San Andreas fault in central California. Results from a net near Hollister show an average creep rate of about one-half inch per year; results from a net near Cholame (about 75 miles southeast of Hollister) show an average creep rate of about one-tenth inch per year. The results also give an angular value which represents the deformation in the crust adjacent to the fault line.

scholarly journals ENZYME EVOLUTION: I. THE IMPORTANCE OF UNTRANSLATABLE INTERMEDIATES

Genetics ◽  
1972 ◽  
Vol 72 (2) ◽  
pp. 297-316
Author(s):  
Arthur L Koch
Keyword(s):  
Rate Constants ◽  
Enzyme Evolution ◽  
Gene Copy ◽  
Mutational Change ◽  
Different Types ◽  
Haploid Species ◽  
Sufficient Magnitude ◽  
A Chain ◽  
The Times ◽  
Mutant Forms

ABSTRACT The proportion of two allelic mutant forms of a haploid species can be calculated from six quantities, the original proportion, the two effective growth rate constants, the two mutation rate constants for the transition from one to the other, and the elapsed time. With a program for carrying out this calculation in a mini-computer, we set about investigating the rates of exploration of multiple intragene changes in populations of enormous numbers over a large number of cell generations. It seemed evident from the outset that unless in the past very different proportions of the different types of mutational changes occurred, then neither the numbers nor the times could have been of sufficient magnitude to account for enzyme evolution by multiple simultaneous changes within a gene to yield a superior protein. Rather, we propose that the more rapid path of enzyme evolution consisted of the sequence: 1) gene duplication, 2) inactivation of a gene copy by a chain-terminating mutation or other mutational change which suppresses transcription and/or translation, 3) multiple base-pair changes and/or small deletions and additions within the non-functioning gene, and finally, 4) reversion of the mutation which was suppressing translation. It is shown that this path will lead to faster advance, if the selective advantages of different forms are dependent on the function of the gene products at certain times in history, while at other times, although this function may be necessary, it is not limiting for growth.

Heat Exchanger Network Synthesis

1995 ◽  
Author(s):  
Christodoulos A. Floudas
Keyword(s):  
Heat Exchanger ◽  
Energy Recovery ◽  
Combinatorial Problem ◽  
Synthesis Problem ◽  
Network Synthesis ◽  
Heat Exchanger Network ◽  
Different Types ◽  
The 1960S ◽  
Heat Exchanger Network Synthesis ◽  
Liquid Vapor

This chapter focuses on heat exchanger network synthesis approaches based on optimization methods. Sections 8.1 and 8.2 provide the motivation and problem definition of the HEN synthesis problem. Section 8.3 discusses the targets of minimum utility cost and minimum number of matches. Section 8.4 presents synthesis approaches based on decomposition, while section 8.5 discusses simultaneous approaches. Heat exchanger network HEN synthesis is one of the most studied synthesis/design problems in chemical engineering. This is attributed to the importance of determining energy costs and improving the energy recovery in chemical processes. The comprehensive review of Gundersen and Naess (1988) cited over 200 publications while a substantial annual volume of studies has been performed in the last few years. The HEN synthesis problem, in addition to its great economic importance features a number of key difficulties that are associated with handling: (i) The potentially explosive combinatorial problem for identifying the best pairs of hot and cold streams (i.e., matches) so as to enhance energy recovery; (ii) Forbidden, required, and restricted matches; (iii) The optimal selection of the HEN structure; (iv) Fixed and variable target temperatures; (v) Temperature dependent physical and transport properties; (vi) Different types of streams (e.g., liquid, vapor, and liquid-vapor); and (vii) Different types of heat exchangers (e.g., counter-current, noncounter-current, multistream), mixed materials of construction, and different pressure ratings. It is interesting to note that the extensive research efforts during the last three decades toward addressing these aforementioned difficulties/issues exhibit variations in their objectives and types of approaches which are apparently cyclical. The first approaches during the 1960s and early 1970s treated the HEN synthesis problem as a single task (i.e., no decomposition into sub-tasks). The work of Hwa (1965) who proposed a simplified superstructure which he denoted as composite configuration that was subsequently optimized via separable programming was a key contribution in the early studies, as well as the tree searching algorithms of Pho and Lapidus (1973). Limitations on the theoretical and algorithmic aspects of optimization techniques were, however, the bottleneck in expanding the applicability of the mathematical approaches at that time.

Supply chain structures for distributing surplus food

2020 ◽  
Vol 31 (4) ◽  
pp. 865-883
Author(s):  
Caroline Sundgren
Keyword(s):  
Supply Chain ◽  
Service Provider ◽  
Closed Loop ◽  
Food Distribution ◽  
Weak Links ◽  
Content Type ◽  
Different Types ◽  
Multiple Case ◽  
A Chain

PurposeNew actors have emerged in the food supply chain in response to the increased awareness of food waste and the need to distribute surplus food. The purpose of this study is to analyse the different supply chain structures that have emerged to make surplus food available to consumers.Design/methodology/approachThis study adopts a qualitative multiple-case study of three new surplus food actors: a surplus food platform, an online retailer and a surplus food terminal. Data sources included interviews, documentary evidence and participatory observations.FindingsThree different types of actor constellations in surplus food distribution have been identified: a triad, a tetrad and a chain. Both centralised (for ambient products) and decentralised supply chain structures (for chilled products) have emerged. The analysis identified weak links amongst new actors and surplus food suppliers. The new actors have adopted the roles of connector, service provider and logistics service provider and the sub-roles of mediator, auditor and consultant.Originality/valueThis paper contributes to research on closed-loop or circular supply chains for the reuse of products in the context of surplus food distribution.

Random collision models in oriented graphs

1979 ◽  
Vol 16 (01) ◽  
pp. 36-44 ◽  
Author(s):  
Yoshiaki Itoh
Keyword(s):  
Oriented Graph ◽  
Dominant Type ◽  
Oriented Graphs ◽  
Collision Model ◽  
Dominance Relations ◽  
Different Types ◽  
The Stability ◽  
Collision Models

We investigate a random collision model for competition between types of individuals in a population. There are dominance relations defined for each pair of types such that if two individuals of different types collide then after the collision both are of the dominant type. These dominance relations are represented by an oriented graph, called a tournament. It is shown that tournaments having a particular form are relatively stable, while other tournaments are relatively unstable. A measure of the stability of the stable tournaments is given in the main theorem.

scholarly journals An ILS-based heuristic applied to the car renter salesman problem

2020 ◽  
Author(s):  
Sávio Soares Dias ◽  
Luidi Gelabert Simonetti ◽  
Luiz Satoru Ochi
Keyword(s):  
Local Search ◽  
Heuristic Method ◽  
Minimum Cost ◽  
Random Variable ◽  
Iterated Local Search ◽  
Variable Neighborhood Descent ◽  
Current State ◽  
Different Types ◽  
Linear Programming Formulation ◽  
Integer Linear Programming Formulation

The present paper tackles the Car Renter Salesman Problem (CaRS), which is a Traveling Salesman Problem variant. In CaRS, the goal is to travel through a set of cities using rented vehicles at minimum cost. The main aim of the current problem is to establish an optimal route using rented vehicles of different types to each trip. Since CaRS is NP-Hard, we herein present a heuristic approach to tackle it. The approach is based on a Multi-Start Iterated Local Search metaheuristic, where the local search step is based on the Random Variable Neighborhood Descent methodology. An Integer Linear Programming Formulation based on a Quadratic Formulation from literature is also proposed in the current study. Computational results for the proposed heuristic method in euclidean instances outperform current state-of-the-art results. The proposed formulation also has stronger bounds and relaxation when compared to others from literature.

scholarly journals High-Performance SiC-Polycrystalline Fiber with Smooth Surface

Ceramics ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 165-174
Author(s):  
Ryutaro Usukawa ◽  
Toshihiro Ishikawa
Keyword(s):  
Oxygen Content ◽  
High Performance ◽  
Smooth Surface ◽  
High Strength ◽  
Degradation Reactions ◽  
Production Processes ◽  
Different Types ◽  
Degradation Reaction ◽  
The Relationship ◽  
Production Conditions

Polymer-derived SiC-polycrystalline fibers show excellent heat-resistance up to 2000 °C, and relatively high strength. Up to now, through our research, the relationship between the strength and residual defects of the fiber, which were formed during the production processes (degradation and sintering), has been clarified. In this paper, we addressed the relationship between the production conditions and the surface smoothness of the obtained SiC-polycrystalline fiber, using three different raw fibers (Elementary ratio: Si1Al0.01C1.5O0.4~0.5) and three different types of reactors. With increase in the oxygen content in the raw fiber, the degradation during the production process easily proceeded. In this case, the degradation reactions (SiO + 2C = SiC + CO and SiO2 + 3C = SiC + 2CO) in the inside of each filament become faster, and then the CO partial pressure on the surface of each filament was considered to be increased. As a result, according to Le Chatelier’s principle, the surface degradation reaction and grain growth of formed SiC crystals would be considered to become slower. That is to say, using the raw fiber with higher oxygen content and closed system (highest CO content in the reactor), a much smoother surface of the SiC-polycrystalline fiber could be achieved. Furthermore, the similar effect obtained by simple oxidation of the SiC-polycrystalline fiber was confirmed, and the advantageous points of the aforementioned process were also considered.

scholarly journals Nodes Localization in 3D Wireless Sensor Networks Based on Multidimensional Scaling Algorithm

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Biljana Risteska Stojkoska
Keyword(s):  
Multidimensional Scaling ◽  
Heuristic Method ◽  
Three Dimensional ◽  
Wireless Sensor ◽  
Indoor Environments ◽  
Smart Environment ◽  
Challenging Problem ◽  
Computing Technology ◽  
Key Technology ◽  
Different Types

In the recent years, there has been a huge advancement in wireless sensor computing technology. Today, wireless sensor network (WSN) has become a key technology for different types of smart environment. Nodes localization in WSN has arisen as a very challenging problem in the research community. Most of the applications for WSN are not useful without a priory known nodes positions. Adding GPS receivers to each node is an expensive solution and inapplicable for indoor environments. In this paper, we implemented and evaluated an algorithm based on multidimensional scaling (MDS) technique for three-dimensional (3D) nodes localization in WSN using improved heuristic method for distance calculation. Using extensive simulations we investigated our approach regarding various network parameters. We compared the results from the simulations with other approaches for 3D-WSN localization and showed that our approach outperforms other techniques in terms of accuracy.

scholarly journals On the Number of Shortest Weighted Paths in a Triangular Grid

Mathematics ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 118
Author(s):  
Benedek Nagy ◽  
Bashar Khassawneh
Keyword(s):  
Euclidean Distance ◽  
Fibonacci Numbers ◽  
Shortest Paths ◽  
Combinatorial Problem ◽  
Infinite Graph ◽  
Binomial Coefficients ◽  
Triangular Grid ◽  
Weighted Graphs ◽  
Different Types ◽  
Weighted Paths

Counting the number of shortest paths in various graphs is an important and interesting combinatorial problem, especially in weighted graphs with various applications. We consider a specific infinite graph here, namely the honeycomb grid. Changing to its dual, the triangular grid, paths between triangle pixels (we abbreviate this term to trixels) are counted. The number of shortest weighted paths between any two trixels of the triangular grid is discussed. For each trixel, there are three different types of neighbor trixels, 1-, 2- and 3-neighbours, depending the Euclidean distance of their midpoints. When considering weighted distances, the positive values α, β and γ are assigned to the ‘steps’ to various neighbors. We gave formulae for the number of shortest weighted paths between any two trixels in various cases by the respective weight values. The results are nicely connected to various numbers well-known in combinatorics, e.g., to binomial coefficients and Fibonacci numbers.

Scaffold Architecture and Properties for Osteoblasts Cell Culture: An Optimization Model and Application by Genetic Algorithm

2015 ◽  
Vol 1753 ◽  
Author(s):  
Maraolina Domínguez-Díaz ◽  
Marco Antonio Cruz-Chavez
Keyword(s):  
Genetic Algorithm ◽  
Cell Culture ◽  
Optimization Model ◽  
Pore Diameter ◽  
Fiber Diameter ◽  
Heuristic Method ◽  
Exact Methods ◽  
Polymeric Scaffolds ◽  
Fitness Value ◽  
Different Types

ABSTRACTIn the developing of scaffolds for cell culture, a large number of architectures with different combinations of properties should be tested to determine the best. This can be costly in time, money and materials. In this paper we have proposed an optimization model that aims to maximize the growth of osteoblasts on polymeric scaffolds by regulating their properties and architecture. Based on the optimization model it was implemented a genetic algorithm to calculate the architecture and properties of the scaffolds. The fiber diameter, pore diameter, porosity, Young's modulus and contact angle of the scaffolds were calculated through four electrospinning parameters: voltage (kV), concentration (% w/v), flow rate (ml/h) and distance (cm). A fitness value was assigned to each scaffold and the highest one was chosen as the best condition for osteoblast growth. The preliminary results obtained by the Genetic Algorithm were consistent with the tendencies reported experimentally in other studies. Also, the methodology established here can be easily adapted to different types of polymers and cells. Finally, the optimization model can be applied not only by means of heuristic method, like a Genetic Algorithm, but also by exact methods.

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