Simplifications In Order Research Articles

An equivalent transformation of multi-objective optimization problems

A new equivalent definition of proper efficiency is presented. With the aid of the new definition of properness, a transformation technique is proved to transform a multi-objective problem to a more convenient one. Some conditions are determined under which the original and the transformed problems have the same Pareto and properly efficient solutions. This transformation could be employed for the sake of convexification and simplification in order to improve the computational efficiency for solving the given problem. Moreover, some existing results about the weighted sum method in the multi-objective optimization literature are generalized using the special case of the proposed transformation scheme.

A method for the simulation and optimization of district heating systems with meshed networks

There are two main methods nowadays for modeling district heating systems, but a key disadvantage of both is that a real network containing loops cannot be described without artificial simplifications in order to eliminate those distinguishing features. However, loops are very common in mature networks that have developed a meshed structure, and make the distribution of mass and heat flows quite characteristic. For this reason, a new process integration method for modeling complex district heating systems containing loops is described in this paper. This method makes it possible to analyze how loops and bottlenecks affect the behavior of the network, as well as the distribution path of the thermal energy in it. The district heating system in the town of Kiruna (located in the north of Sweden) has a complex design with several loops and part of it is used in the paper as an example of application.

The PACTUM model: Product analysis of cost and time using mathematics

Establishing a mathematical supply-chain model is a proposition that has received attention due to its inherent benefits of evolving global supply-chain efficiencies. This paper discusses the prevailing relationships found within apparel supply-chain environments, and contemplates the complex issues indicated for constituting a mathematical model. Principal results identified within the data suggest, that the multifarious nature of global supply-chain activities require a degree of simplification in order to fully dilate the necessary factors which affect, each subsection of the chain. Subsequently, the research findings allowed the division of supply-chain components into subsections, which amassed a coherent method of product development activity. Concurrently, the supply-chain model was found to allow systematic mathematical formulae analysis, of cost and time, within the multiple contexts of each subsection encountered. The paper indicates the supply-chain model structure, the mathematics, and considers how product analysis of cost and time can improve the comprehension of product lifecycle management.

Mathematical supply-chain modelling: Product analysis of cost and time

Establishing a mathematical supply-chain model is a proposition that has received attention due to its inherent benefits of evolving global supply-chain efficiencies. This paper discusses the prevailing relationships found within apparel supply-chain environments, and contemplates the complex issues indicated for constituting a mathematical model. Principal results identified within the data suggest, that the multifarious nature of global supply-chain activities require a degree of simplification in order to fully dilate the necessary factors which affect, each sub-section of the chain. Subsequently, the research findings allowed the division of supply-chain components into sub-sections, which amassed a coherent method of product development activity. Concurrently, the supply-chain model was found to allow systematic mathematical formulae analysis, of cost and time, within the multiple contexts of each subsection encountered. The paper indicates the supply-chain model structure, the mathematics, and considers how product analysis of cost and time can improve the comprehension of product lifecycle management.

Simplified Occupancy Grid Indoor Mapping Optimized for Low-Cost Robots

This paper presents a mapping system that is suitable for small mobile robots. An ad hoc algorithm for mapping based on the Occupancy Grid method has been developed. The algorithm includes some simplifications in order to be used with low-cost hardware resources. The proposed mapping system has been built in order to be completely autonomous and unassisted. The proposal has been tested with a mobile robot that uses infrared sensors to measure distances to obstacles and uses an ultrasonic beacon system for localization, besides wheel encoders. Finally, experimental results are presented.

Taxing the Informal Economy: Challenges, Possibilities and Remaining Questions*

SummaryRecent years have witnessed significantly increased attention to the challenge of taxing small businesses in the informal sector. However, much of this recent attention has remained focused on comparatively technical issues of revenue maximisation and policy design. This paper argues that this debate should focus increasingly on the wider development implications of informal sector taxation, as well as the political and institutional barriers to improved performance.When considering the merits of committing scarce resources to taxing small informal sector firms, debate has frequently focused on limited revenue potential, high costs of collection and potentially perverse impacts on small firms. By contrast, recent arguments have increasingly emphasised more indirect benefits of informal taxation in relation to economic growth, tax compliance and governance. These potentially broader benefits are increasingly finding support in recent research, but they are contingent on government support and consequently demand further attention.When we turn our attention away from whether tax authorities should tax small informal businesses towards the challenge of how to do so more effectively, we again argue that a broader frame of analysis is needed. Most existing research has focused on developing less distortionary tax regimes and on tax simplification in order to reduce the costs of compliance. However, while important, there strategies remain too narrow. Encouraging tax compliance demands not only lowering costs but also strengthening the potential benefits of formalisation, from increased security to new economic opportunities. As importantly, successful reform needs political support from political leaders, tax administrators and taxpayers alike. This demands greater attention to strengthening political incentives for reform, through strategic policy, administrative and institutional reform. With this in mind, the paper highlights a number of recent experiences that have sought to address these challenges, but which need further study.

Numerical Simulation of Steady and Unsteady Motion for an AUV with Complex Geometry

Abstract This article simulates steady and unsteady motion of a complex geometry AUV (Autonomous Underwater Vehicle) pumped by four stern tubes. The model is similar to actual body without any simplification in order to get high resolution result, meshed by hybrid grids with prismatic grids near body while unstructured grids filling the left domain. Integrating to RNG k-e equation by cell centered finite volume scheme, the steady resistance is got and compared with that of experiment. Dealing with this analytical data we correct the experiment data, within 1.7 percent difference. During unsteady motion, added moment source is added to moment equation, while implicit dual time is applied to discretize the time dependent conserved variables, the complex pump-propelled AUV moving from stationary to a constant velocity (steady velocity) is simulated, with acceleration dicreasing in exponential with time. Its drag and corresponding velocity vector are obtained at each time step. The drag at constant velocity is validated compared with that of steady motion.

Review of the Book “Optimization in Computer Engineering—Theory and Applications”: Chapter 8—Applying Graph Coloring to Frequency Assignment

This book focuses on the relationship between theory and applications of various optimization problems in computer engineering. In the first half of the book the theoretical foundations are presented, such as some selected graph algorithms, integer linear programming and complexity theory. The second half of the book brings the theory closer to the reader by applying them to real-world optimization problems. Its aim is to bridge the often significant gap between theory and applications bringing additional value to both: the theory becomes more interesting in light of a possible application and understanding the hardness and possible solutions of the real-world problem definitely benefits from a strong theoretical background. Chapter 8 is a good example of the above. Here the authors present several versions of the frequency assignment problem (FAP), which is an important practical optimization problem arising in wireless network design. It is shown how FAP can be reduced to the earlier presented graph coloring problem. It is interesting to note that often the practical problem needs significant simplification in order to fit into the model that the theory is able to handle, or the theoretical problem needs to be extended to be able to model the needs of the practical application. Various generalizations of the simple graph coloring problem such as list coloring and T-coloring are introduced to model the constraints of the FAP. With this reduction the specific engineering problem can be han-dled through well-understood mathematical models. Besides showing the reduction to the graph coloring problem, the authors apply a graph coloring solver on industry benchmark FAP instances to further understand the characteristics of the real-world FAP. They show that there are significant differences in the difficulty of the problem on random and real-world graphs and that the parameters of the particular instance play a crucial role in the hardness of the problem. They show that the FAPs show a phase transition property in every input parameter, ie. there is a critical parameter combination where the problem gets extremely hard, but otherwise the problem can be solved relatively easily even on large real-world networks. Readers will surely benefit from the unique nature of the book that brings theory and applications close together in a well-understandable yet theoretically solid way.

Taxing the Informal Economy: Challenges, Possibilities and Remaining Questions

Recent years have witnessed significantly increased attention to the challenge of taxing small businesses in the informal sector. However, much of this recent attention has remained focused on comparatively technical issues of revenue maximisation and policy design. This paper argues that this debate should focus increasingly on the wider development implications of informal sector taxation, as well as the political and institutional barriers to improved performance. When considering the merits of committing scarce resources to taxing small informal sector firms, debate has frequently focused on limited revenue potential, high costs of collection and potentially perverse impacts on small firms. By contrast, recent arguments have increasingly emphasised more indirect benefits of informal taxation in relation to economic growth, tax compliance and governance. These potentially broader benefits are increasingly finding support in recent research, but they are contingent on government support and consequently demand further attention. When we turn our attention away from whether tax authorities should tax small informal businesses towards the challenge of how to do so more effectively, we again argue that a broader frame of analysis is needed. Most existing research has focused on developing less distortionary tax regimes and on tax simplification in order to reduce the costs of compliance. However, while important, there strategies remain too narrow. Encouraging tax compliance demands not only lowering costs but also strengthening the potential benefits of formalisation, from increased security to new economic opportunities. As importantly, successful reform needs political support from political leaders, tax administrators and taxpayers alike. This demands greater attention to strengthening political incentives for reform, through strategic policy, administrative and institutional reform. With this in mind, the paper highlights a number of recent experiences that have sought to address these challenges, but which need further study.

Simplification of Marketing Scheme for Business Start-Ups

This paper deals with the topic of marketing planning simplification in order to use it for start-ups in the field of small & medium enterprises. There are 11 main question areas which can be used for logical and empiric marketing approaches. These questions are elaborated on the basis of standard marketing planning methods and approaches from the literature given in references.

The 'Science City' as a System Coupler in Fragmented Strategic Urban Environments?

This paper explores the rise of 'urban science' in the context of contemporary discourses of strategic urban management. 'Urban science' – developing precincts to stimulate knowledge-based development – is founded on an assumption that the positive-sum nature of projects means that all partners share a common set of interests in the projects, and that these interests are around promoting knowledge-based urban development (KBUD). This paper explores this simplification in order to develop a more robust understanding of the role of knowledge-based urban development processes and discourses in contemporary urban governance. Through a reflection on a notionally successful case study from the east of the Netherlands, the paper explores how one particular urban science project led to the development of strategic urban capacity; partners were able to agree to pool funding towards collective regional economic development policy in a way that had not been possible a decade previously. The paper explores the way the urban science project held these diverse interests together, and highlights that much of urban science as a set of practices is embedded as much in traditional modes of territorial development as in attempts to stimulate KBUD. The paper finishes with an argument that more systematic consideration of the relation of KBUD discourses to more traditional territorial development processes is necessary for proper examination of these emerging economic development discourses and paradigms.

Rate-distortion optimization for progressive compression of 3D mesh with color attributes

We propose a new lossless progressive compression algorithm based on rate-distortion optimization for meshes with color attributes; the quantization precision of both the geometry and the color information is adapted to each intermediate mesh during the encoding/decoding process. This quantization precision can either be optimally determined with the use of a mesh distortion measure or quasi-optimally decided based on an analysis of the mesh complexity in order to reduce the calculation time. Furthermore, we propose a new metric which estimates the geometry and color importance of each vertex during the simplification in order to faithfully preserve the feature elements. Experimental results show that our method outperforms the state-of-the-art algorithm for colored meshes and competes with the most efficient algorithms for non-colored meshes.

Dimensional Optimization Design of the Four-Cable-Driven Parallel Manipulator in FAST

For the design of the five-hundred-meter aperture spherical radio telescope (FAST), a four-cable-driven parallel manipulator, which is long in span and heavy in weight, is adopted as the first-level adjustable feed-support system. The purpose of this paper is to optimize dimensions of the four-cable-driven parallel manipulator to meet the workspace requirement of constraint condition in terms of cable tension and stiffness. Accordingly, this optimization method adopts catenary simplification in order to set up the cable tension equilibrium equations, preliminarily optimizing three important dimensional parameters. Stiffness of the cable is also taken into consideration because of its effect on work performance of a cable-driven parallel manipulator. However, the stiffness value of a cable-driven parallel manipulator is not totally credible by traditional theoretical analysis. Therefore, an experimental method for stiffness analysis is presented in this paper. It applies Buckingham π theorem to set up an experimental stiffness similarity model to obtain a more credible stiffness value, which is used in the optimization process. In this way, dimensional optimization is realized with a set of optimized dimensions for building the feed-support system in the FAST. More importantly, the stiffness similarity model can be universally adopted in stiffness analysis of other large cable-driven parallel manipulator.

Evaluating an environmental indicator: Case study of MERLIN, a method for assessing the risk of nitrate leaching

The need to achieve acceptable levels of nitrate in drinking water has led to the development of simulation models and indicators for assessing the environmental performance of agricultural practices. These indicators are necessarily based on simplifications in order to meet the practical constraints of feasibility, but they should nevertheless meet scientific standards, especially as regards their validation. The overall objective of this paper is to evaluate the MERLIN indicator and sub-indicators, an assessment method developed by French agricultural advisors. This tool estimates and classes the risks of water pollution by nitrates, integrating farmer practices both during crop cultivation and in between two successive crops, as well as soil sensitivity to leaching. The evaluation was performed according to the methodological framework proposed by Bockstaller and Girardin [Bockstaller, C., Girardin, P., 2003. How to validate environmental indicators? Agric. Syst. 76, 639–653]: design, output and end-use validation. Design validation involved submission of the method to experts and checking the sub-indicators against literature. Output validation was carried out by comparing real values to indicator outputs. End-use validation was based on information gathered by users. In particular we compared output data from the original method with that of users that had adapted the method to their situation, in order to assess the consequences of these changes. The first step confirmed that the assumptions of MERLIN and its sub-indicators are scientifically sound. However, the weighting of the different sub-indicators raised questions. The second output validation step gave acceptable results for the EQUIF sub-indicator but the MERLIN test highlighted the need for additional experimental data before validation. This approach also showed that improvements in the precision of parameters do not necessarily increase the accuracy of the classification. The last step confirmed that the indicator is considered useful by decision-makers but also reveals that in some cases users adapt parameter values to their situation. This has lead to the production of a user guide which defines the method more clearly to avoid numerous adaptations by users.

Nineteenth-Century Europe

This volume is published as part of Palgrave Macmillan's ‘History of Europe’ series. Chronologically, it is concerned with the ‘long nineteenth century’, stretching from the French Revolution of 1789 to the outbreak of the First World War. Two qualities distinguish this book from recently published general histories of the period: the prominence accorded to politics, and the geographical breadth with coverage extending to the peripheries as well as western and central Europe. The rise of mass politics is the central theme adopted by Rapport, and this lends cohesion to a book that is otherwise characterised by complexity, nuance and indeed qualification. The emergence of mass politics is followed in eighteen chapters grouped into four chronological parts with 1815, 1850 and 1879 selected as breaks. Rapport's coverage of the Napoleonic period in particular provides an indicator of the book's overall quality for this reviewer. Rapport handles it well: a book such as this must be selective and engage in simplification in order to provide an accessible overview, but without creating distortion. Rapport succeeds in this when writing on Napoleonic Europe, where he draws on recent work and arrives at a fair conclusion that recognises the complexities of this ambiguous regime. As noted, a feature of this book is nuance—though in the positive sense of challenging existing assumptions rather than refusing to take sides. For example, with respect to 1789, Rapport unambiguously supports the revisionist interpretation in playing down the significance of the social transformation that occurred in France at this time. Instead, he rightly stresses social continuity, giving due weight to modernising impulses under the Old Regime, while highlighting the durability of the old noble élite that, as late as 1846, accounted for a quarter of the French legislature.

Application of Schwarz-Christoffel Mapping to Permanent-Magnet Linear Motor Analysis

Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear synchronous motors. These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this paper, an elegant semianalytical approach is presented to acquire the force profile. First, the magnetic field distribution in the air gap is determined by means of Schwarz-Christoffel (SC) mapping. The SC mapping allows a slotted structure of the machine to be mapped to a geometrically simpler domain for which analytic solutions are available. Subsequently, the field solution in the slotted structure can be determined by applying the mapping function to the field distribution in the simplified domain. From the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The results are compared with those from the commonly used equivalent magnetic circuit modeling and 2-D FEM software to demonstrate the accuracy which can be reached by application of the SC method.

Aeration optimization of a wastewater treatment plant using genetic algorithm

AbstractThis paper discusses the aeration optimization problem of an intermittently aerated wastewater treatment plant by the application of a stochastic optimization approach, genetic algorithm (GA). In this process, the alternating aerobic and anoxic conditions needed for nitrogen removal are realized in a single basin by switching the aeration sequentially on and off. Since the operation of these plants may be challenging both for economical and technical reasons, several previous studies have investigated the possibility of reduction of the operating cost, however, it turned out that for long‐term application these methods can save only limited per cent of the cost. Furthermore, these investigations also had to make problem simplifications in order to use optimization methods which usually need significant computational effort to give—only a local optimum—of the problem. The objective of this paper is to demonstrate an optimization procedure to minimize the pollution load in the receiving water body, rather than the operational cost, using a complete model of the treatment process. The results were evaluated based on rigorous evaluation criteria and showed that using GA‐based optimization strategy an optimal solution can be efficiently found where both pollution load and energy consumption savings can reach up to 10% compared to traditional control strategies. Copyright © 2007 John Wiley & Sons, Ltd.

Inferential language models for information retrieval

Language modeling (LM) has been widely used in IR in recent years. An important operation in LM is smoothing of the document language model. However, the current smoothing techniques merely redistribute a portion of term probability according to their frequency of occurrences only in the whole document collection. No relationships between terms are considered and no inference is involved. In this article, we propose several inferential language models capable of inference using term relationships. The inference operation is carried out through a semantic smoothing either on the document model or query model, resulting in document or query expansion. The proposed models implement some of the logical inference capabilities proposed in the previous studies on logical models, but with necessary simplifications in order to make them tractable. They are a good compromise between inference power and efficiency. The models have been tested on several TREC collections, both in English and Chinese. It is shown that the integration of term relationships into the language modeling framework can consistently improve the retrieval effectiveness compared with the traditional language models. This study shows that language modeling is a suitable framework to implement basic inference operations in IR effectively.

Causing Death for Compassionate Reasons in American Law

There is no single American law on causing death for compas sionate reasons. The federal distribution of powers leaves the rele vant areas of law mainly to the states. Federal constitutional law has been invoked only in connection with the outer limits within which state law may govern. So far it has not been successfully employed to invalidate state regulation. Consequently, there are at least 50 laws dealing with end-of-life decisions. Nevertheless, the basic organiza tion of the legal issues has turned out to be similar in almost all American jurisdictions and I will treat the subject generally. It is important to be mindful, however, that, in this respect. I have adopted a significant simplification in order to facilitate exposition.

Multi-Input Fuzzy control of an inverted pendulum using an armature controlled DC motor

This paper presents a design methodology to stabilize a class of multi-variant nonlinear system after a high disturbance occurs. It investigates application of Takagi-Sugeno type fuzzy controller (T-S-FC) to an inverted pendulum mechanism, actuated by an armature-controlled DC electrical motor.Fuzzy controllers use heuristic information in developing design methodologies for control of non-linear dynamic systems. This approach eliminates the need for comprehensive knowledge and mathematical modeling of the system, and in cases of more complex systems, approximation and simplifications in order to achieve feasible mathematical model is not required.The paper presents the stages of development of the Fuzzy Controller for an inverted pendulum by developing a two-input, Mamdani type system. It evaluates the performance of the system. Then a four-input T-S-FC type is developed. The research compares performances of each controller and presents the result of tests. A model for a DC motor is developed in this study, in order to measure the effect of time delays and response time caused by inherent properties of the physical system. The final part will demonstrate the complete operational system with the DC electrical motor included in the test system.