Path planning algorithm for a car-like robot based on cell decomposition method

This project proposes an obstacle avoiding path planning algorithm based on cell decomposition method for a car-like robot. Dijkstra’s algorithm is applied in order to find the shortest path. Using cell decomposition, the free space of the robot is exactly partitioned into cells. Then, the connectivity graph is created followed by calculating the shortest path by Dijkstra’s algorithm. This project also concerns the robot kinematic constraints such as minimum turning radius. Thus, kinematic modeling and Bezier curve have been used to obtain a feasible path. The algorithm is able to obtain a curvature bounded path with sub-optimal curve length while taking cell decomposition as reference skeleton. The C-space concept has been applied in this situation. The obstacles on the map are expanded according to the size of car-like robot, so that the robot could be treated as points on this map and the coordinates of the map is corresponding to these points. The simulation and experimental result shows the algorithm can obtain the collision free path which satisfies the curvature constraint and approaches the minimal curve length for a car-like robot

Modeling an integrated market for sawlogs, pulpwood and forest bioenergy

Traditionally, most applications in the initial stage of forest supply chain deal with sawlogs to sawmills, pulpwood to pulp or paper mills and forest residues to heating plants. However, in the past decades, soaring prices of fossil fuel, global awareness about CO2 emission and increasing attention to domestic resource security have boosted the development of alternative renewable energy, among which forest bioenergy is the most promising and feasible choice for medium- and large-scale heating and electricity generation. Different subsidies and incentive policies for green energy further promote the utilization of forest bioenergy. As a result, there is a trend that pulpwood may be forwarded to heating plants as complementary forest bioenergy. Though pulpwood is more expensive than forest residues, it is more efficient to transport and has higher energy content. The competition between traditional forest industries and wood-energy facilities, expected to grow in the future, is very sensitive for the forest companies as they are involved in all activities. In this paper, we develop a model that all raw materials in the forest, i.e. sawlogs, pulpwood and forest residues, and byproducts from sawmills, i.e. wood chips and bark, exist in an integrated market where pulpwood can be sent to heating plants as bioenergy. It represents a multi-period multi-commodity network planning problem with multiple sources of supply, i.e. pre-selected harvest areas, and multiple kinds of destination, i.e. sawmills, pulp mills and heating plants. The decisions incorporate purchasing the raw materials in harvest areas, reassigning byproducts from sawmills, transporting those assortments to different points for chipping, storing, wood-processing or wood-fired, and replenishing fossil fuel when necessary. Moreover, different from the classic wood procurement problem, we take the unit purchasing costs of raw materials as variables, on which the corresponding supplies of different assortments linearly depend. With this price mechanism, the popularity of harvest areas can be distinguished. The objective of the problem is to minimize the total cost for the integrated market including the purchasing cost of raw materials. Therefore, the model is a quadratic programming (QP) problem with a quadratic objective function and linear constraints. A large case study in southern Sweden under different scenario assumptions is implemented to simulate the integrated market and to study how price restriction, market regulation, demand fluctuation, policy implementation and exogenous change in price for fossil fuel will influence the entire wood flows. Pair-wise comparisons show that in the integrated market, competition for raw materials between forest bioenergy facilities and traditional forest industries pushes up the purchasing costs of pulpwood. The results also demonstrate that resources can be effectively utilized with the price mechanism in supply market. The overall energy value of forest bioenergy delivered to heating plants is 23% more than the amount in the situation when volume and unit purchasing cost of raw materials are fixed.Forest supply chain; integrated market; bioenergy; wood procurement; wood distribution; quadratic programming

Fungal cellulase; production and applications: minireview

Cellulose is the most abundant biomaterial derived from the living organisms on the earth; plant is the major contributor to the cellulose pool present in the biosphere. Cellulose is used in variety of applications ranging from nanomaterials to biofuel production. For biofuel production, cellulose has first to be broken-down into its building blocks; β-D-glucosyl unit which subsequently can be fermented to different product such as ethanol, acetic acids, among others. Cellulase is the enzymatic system, which degrades cellulose chains to glucose monomers. Cellulase is a group of three enzymes endoglucanase, exoglucanases and β-glucosidases which act together to hydrolyze cellulose to glucose units. Cellulases are found in bacteria, fungi, plants, and some animals. Fungi are the preferred source of cellulase for industrial applications since they secrete large quantities of cellulase to culture medium. Despite a remarkable number of fungi found to produce cellulase enzymes, few have been extensively investigated because they produce large quantities of these enzymes extracellularly. In this mini-review, the production of cellulase from fungi and the parameters affecting cellulase production are discussed briefly on light of recent publications. Furthermore, potential applications of cellulase enzymes are highlighted

MODELING OPERATING RATE DECISIONS IN THE CANADIAN FOREST INDUSTRIES

This article examines the problem of characterizing production structures when there is input fixity but fixed inputs can be utilized with varying intensities. Unless the rate of utilization of quasi-fixed factors is adequately measured, primal or dual characterizations of producer behavior common in the empirical literature may not be valid. The problem is overcome by specifying another input, the operating rate, which firms can use the short run to adjust to unexpected market changes when there is quasi-fixity in production. The model is applied to the Canadian pulp and paper and sawmilling industries. The results do not permit rejection of the hypotheses of quasi-fixity and varying utilization of quasi-fixed factors in the short run. A model of instantaneous adjustment of factor inputs is clearly outperformed by the quasi-fixity model incorporating an operating rate decision.Production Economics,

"Effects of Information Technology and Aging Work Force on Labor Demand and Technological Progress in Japanese Industries: 1980-1998"

The purpose of this paper is two-folds. First, we examine the direction and the magnitude of substitutability or complementarity between information- and communication-related capital stock and various labor inputs to know about differential impacts of information and com-munication technology on labor demand. In this way, we can obtain information about what segments of workers information and communication technology can effectively substu-tute for. Second, we estimate contribution of information- and communication-related capital stock and various labor inputs on the value-added growth of the Japanese economy in the recent turbulent era (1980s and 1990s) and explore factors determining technological progress. In particular, we investigate whether rapid accumulation of information-related capital stock has a positive effect on technological progress, examining IT externality. We also discern the effect of compositional changes in labor inputs on technological progress, examining the inflexibility issue and IT-induced technological obsolescence issue. Three remarkable facts emerge from our result with respect to substitutability/complementarity issues. First, IT capital stocks are shown to be significant substitutes for young workers with a low education level, whereas old workers with a low education level are consistently quasi-fixed in all industries under investigation. Second, IT capital stocks have complemen-tary relationship with workers with a high education level in many industries. Third, workers with a high education level and those with a low education level are substitutes. These all suggest that IT investment and human capital accumulation are of utmost importance to overcome possible shortage (in relative terms) of young workers with a low education level caused by rapidly aging population. As for IT externality, we find at first positive correlation between IT stocks and techno-logical progress in manufacturing, suggesting a strong externality effect of IT capital stocks. In the first glance it is very promising, since this suggests that this IT externality can be used for boosting productivity growth. However, the correlation is not robust. First, if non-manufacturing industries are included, the correlation vanishes. Second, if "Electrical Machinery" is excluded from the sample of manufacturing, the correlation also vanishes. Thus, we fail to discern clear-cut evidence for IT externality. Thus, the proposition that IT "revolution"can pop up productivity growth and can counter the pressure of aging population is not supported by our data, although investment in IT-producing industries is surely an important driving force for economic growth through substitution effects. As for the effect of labor force composition on the rate of technological progress, the results do not support that the "inflexible old worker" hypothesis of productivity slowdown. There is no correlation between the rate of technological progress and the ratio of old workers with low education in the total labor inputs. However, the results suggest that information technology development in the 1990s has a negative impact on the past strength of the Japanese economy: productivity increase through high-education workers' learning by doing. In manufacturing industries where Japan has been strong, the rate of technological progress in the 1980s has positive (though weak) correlation with "maturing" high-education labor force. That is, the ratio of old well-educated workers in the total labor inputs has a positive (though weak) effect on technological progress. This suggests that the increased average skill among well-educated workers due to longer experience has a positive effect to improve productivity. However, the relationship changes significantly in the 1990s, and we have rather negative relationship. The nature of technological progress apparently changed adversely.

Designing and Evaluating Sustainable Logistics Networks

The objective in this paper is to shed light into the design of logistic networks balancing profit and the environment. More specifically we intend to i) determine the main factors influencing environmental performance and costs in logistic networks ii) present a comprehensive framework and mathematical formulation, based on multiobjective programming, integrating all relevant variables in order to explore efficient logistic network configurations iii) present the expected computational results of such formulation and iv) introduce a technique to evaluate the efficiency of existing logistic networks.The European Pulp and Paper Industry will be used to illustrate our findings.Eco-efficiency;Data Envelopment Analysis (DEA);Multi-Objective Programming (MOP);Supply Chain Design;Sustainable Supply Chain

A multiobjective optimization framework for multicontaminant industrial water network design.

The optimal design of multicontaminant industrial water networks according to several objectives is carried out in this paper. The general formulation of the water allocation problem (WAP) is given as a set of nonlinear equations with binary variables representing the presence of interconnections in the network. For optimization purposes, three antagonist objectives are considered: F1, the freshwater flow-rate at the network entrance, F2, the water flow-rate at inlet of regeneration units, and F3, the number of interconnections in the network. The multiobjective problem is solved via a lexicographic strategy, where a mixed-integer nonlinear programming (MINLP) procedure is used at each step. The approach is illustrated by a numerical example taken from the literature involving five processes, one regeneration unit and three contaminants. The set of potential network solutions is provided in the form of a Pareto front. Finally, the strategy for choosing the best network solution among those given by Pareto fronts is presented. This Multiple Criteria Decision Making (MCDM) problem is tackled by means of two approaches: a classical TOPSIS analysis is first implemented and then an innovative strategy based on the global equivalent cost (GEC) in freshwater that turns out to be more efficient for choosing a good network according to a practical point of view

Optimization of molybdenite flotation using response surface method

Purpose. The paper is aimed to study the molybdenite flotation from a low-grade uranium ore containing 0.2% of Mo. Methods. Three control parameters including frother (MIBC) dosage, collector (gasoline) dosage and pH, each in five levels, were investigated. Response surface methodology (RSM) was performed for statistical design and analysis of experiments and process modeling. Four quadratic mathematical models were derived for prediction of Mo recovery and Mo grade. Findings. Analysis of variance showed that frother and collector dosage were the most significant factors affecting Mo recovery and grade. In process optimization, maximum values of Mo recovery and grade were achieved as 79.13% and 2.93%, respectively. Optimum frother concentration of 78.93 g/t, gasoline dosage of 507.70 g/t, and pH of 9.77, for Mo recovery were obtained. However, in optimization studies, a case proposed the model in which the same consumption of reagents is used. Originality. There is a recognized need for type of uranium ore which contains Molybdenite, therefore working on molybdenite removing from this ore helps to recover uranium in the next steps. This research provides a novel approach to gain the optimum recovery and grade to extract uranium so easily. Practical implications. This study showed that response surface methodology could be effectively used for flotation process modeling as well as finding an optimum condition to achieve maximum recovery and grade under minimum consumption of flotation reagents.Мета. Дослідження особливостей процесу флотації молібденіту з низькозбагаченої уранової руди, що містить 0.2% молібдену. Методика. Проаналізовано три контрольних параметра флотації – дозу спінювача (метил-ізобутил-карбінол), колекторне (газолінове) дозування і ph (кожен – у п’яти різницях рівнів). Для статистичного розрахунку, аналізу експериментів і моделювання процесу флотації застосовано метод поверхневого відклику (МПВ). Були розроблені чотири квадратичні математичні моделі для розрахункових даних отримання Мо і визначення його якості. Результати. Встановлено, що спінювач і колекторне дозування є найбільш впливовими факторами при отриманні Мо та його якості. У процесі оптимізації максимальні рівні отримання Мо та якості були, відповідно, 79.13% і 2.93%. Виявлено наступну оптимальну концентрацію для Мо: спінювач – 78.93 г/т, газолінове дозування – 507.70 г/т, pH – 9.7, що підтверджено моделюванням. Наукова новизна. Запропоновано інноваційний підхід для отримання легкого й оптимального способу відновлення і ступеня вилучення урану до високої якості. Практична значимість. Метод поверхневого відклику може ефективно застосовуватися для моделювання процесу флотації з метою визначення оптимальних умов досягнення максимальної рекуперації та якості при мінімальних витратах флотаційних реагентів.Цель. Исследование особенностей процесса флотации молибденита из низкообогащенной урановой руды, содержащей 0.2% молибдена. Методика. Проанализированы три контрольных параметра флотации – доза вспенивателя (метил-изобутил-карбинол), коллекторная (газолиновая) дозировка и pH (каждый – в пяти разностях уровней). Для статистического расчета, анализа экспериментов и моделирования процесса флотации применен метод поверхности отклика (МПО). Были разработаны четыре квадратичные математические модели для расчетных данных получения Мо и определения его качества. Результаты. Установлено, что вспениватель и коллекторная дозировка являются наиболее влияющими факторами при получении Мо и его качества. В процессе оптимизации максимальные уровни получения Мо и качества были, соответственно, 79.13% и 2.93%. Выявлена следующая оптимальная концентрация для Мо: вспениватель – 78.93 г/т, газолиновая дозировка – 507.70 г/т, pH – 9.7, что подтвержденно моделированием. Научная новизна. Предложен инновационный подход для получения легкого и оптимального способа восстановления и степени извлечения урана до высокого качества. Практическая значимость. Метод поверхностного отклика может эффективно применяться для моделирования процесса флотации с целью определения оптимальных условий достижения максимальной рекуперации и качества при минимальном расходе флотационных реагентов.The financial support of the Jaber Ibn Hayan Research Laboratories, Nuclear Science and Technology Research Institute and Mr. Hasan Sedighi helps and the university of Imam Khomeini (IKIU) is gratefully acknowledged

The Clean Air Act Amendments and Firm Investment in Pollution Abatement Equipment

The command-and-control approach to environmental regulation requires that firms install prescribed technologies to meet specified goals. However, environmental regulations change frequently; in addition, the enforcement agency cannot perfectly monitor firm compliance. We examine the impact of uncertainties surrounding the enactment and the enforcement of the Clean Air Act Amendments of 1990 on firm investment in air pollution abatement equipment. We find that our measures of the likelihood of CAAA passage clearly affect a firm's investment in pollution equipment. Enforcement actions also affect a firm's investment, but these effects are weaker and are statistically significant only after enactment