An Integrated MCDM Model for Conveyor Equipment Evaluation and Selection in an FMC Based on a Fuzzy AHP and Fuzzy ARAS in the Presence of Vagueness

The conveyor system plays a vital role in improving the performance of flexible manufacturing cells (FMCs). The conveyor selection problem involves the evaluation of a set of potential alternatives based on qualitative and quantitative criteria. This paper presents an integrated multi-criteria decision making (MCDM) model of a fuzzy AHP (analytic hierarchy process) and fuzzy ARAS (additive ratio assessment) for conveyor evaluation and selection. In this model, linguistic terms represented as triangular fuzzy numbers are used to quantify experts’ uncertain assessments of alternatives with respect to the criteria. The fuzzy set is then integrated into the AHP to determine the weights of the criteria. Finally, a fuzzy ARAS is used to calculate the weights of the alternatives. To demonstrate the effectiveness of the proposed model, a case study is performed of a practical example, and the results obtained demonstrate practical potential for the implementation of FMCs.     

Using a network framework to quantitatively select ecological indicators

Ecological indicators are often constructed as an integrated set to represent key information and characteristics of the ecosystem which are tightly linked to management objectives. As an effective tool, ecological indicators play an increasingly important role in ecosystem monitoring, assessment and management. Reasonable selection of an indicator is a prerequisite for effectively using it. A defined protocol with scientific rigor to select ecological indicators is imperative to solve the challenges in ecological indicator selection. This paper compares the Causal Network (CN) with the Ecological Hierarchy Network (EHN) as a framework to select ecological indicators. These frameworks are not exclusive but interdependent in constructing a network framework. Based on the network framework, a quantitative ecological indicator selection method is demonstrated through a theoretical example. In the selection process, the criteria and requirements considering the balance of science and utility are proposed and translated into quantitative constraints of a selection model. By resolving the model under a mathematical operation, the human arbitrary disturbance will be reduced and random selection minimized.     

Liver transplantation of hepatic stem cells: potential use for treating liver diseases

Hepatic stem cells are an alternative means for repopulating the liver after various injuries instead of liver transplantation. The first step before use is to select stem cells that will be good candidates. This review discusses the different candidates including fetal progenitor bipotential hepatic stem cells; adult hepatocytes, which can be considered as unipotential committed stem cells; and oval cells, a type of nonparenchymal pluripotential hepatic stem cell. The advantages and disadvantages of each type of cell are discussed and several other possible alternatives, such as the use of hematopoietic stem cells are analyzed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Summation of afterhyperpolarization after a doublet in fast motoneurones of the rat spinal cord

Motoneurones located in lumbar segments (L4-L5) of the rat spinal cord were activated antidromically by stimulation of the sciatic nerve. Records following a single pulse and double stimuli were collected from fast motoneurones and in each case voltage and time parameters of the action potential and afterhyperpolarization (AHP) were compared to respective values calculated for a simulated doublet - obtained by mathematical summation of two individual single potentials. The most prominent differences between experimentally recorded and simulated potentials concerned spike duration and the AHP half-decay times, with significantly lower values obtained for the simulated doublets. Tendencies for a higher AHP amplitude, shorter AHP peak time and higher AHP area were observed in mathematically modeled doublets, though no statistical differences were present in comparison to experimental data. Results indicated a non-linear summation of the AHP after double stimuli running in a short interval. These observations suggest that alterations in the generation of the AHP, mainly based on the sustained activity of K(Na+) channels, influence time-intervals in motoneuronal discharge pattern and this way force development of individual motor units during muscle activity.     

Modeling the Effects of Harvest Alternatives on Mitigating Oak Decline in a Central Hardwood Forest Landscape

Oak decline is a process induced by complex interactions of predisposing factors, inciting factors, and contributing factors operating at tree, stand, and landscape scales. It has greatly altered species composition and stand structure in affected areas. Thinning, clearcutting, and group selection are widely adopted harvest alternatives for reducing forest vulnerability to oak decline by removing susceptible species and declining trees. However, the long-term, landscape-scale effects of these different harvest alternatives are not well studied because of the limited availability of experimental data. In this study, we applied a forest landscape model in combination with field studies to evaluate the effects of the three harvest alternatives on mitigating oak decline in a Central Hardwood Forest landscape. Results showed that the potential oak decline in high risk sites decreased strongly in the next five decades irrespective of harvest alternatives. This is because oak decline is a natural process and forest succession (e.g., high tree mortality resulting from intense competition) would eventually lead to the decrease in oak decline in this area. However, forest harvesting did play a role in mitigating oak decline and the effectiveness varied among the three harvest alternatives. The group selection and clearcutting alternatives were most effective in mitigating oak decline in the short and medium terms, respectively. The long-term effects of the three harvest alternatives on mitigating oak decline became less discernible as the role of succession increased. The thinning alternative had the highest biomass retention over time, followed by the group selection and clearcutting alternatives. The group selection alternative that balanced treatment effects and retaining biomass was the most viable alternative for managing oak decline. Insights from this study may be useful in developing effective and informed forest harvesting plans for managing oak decline.     

Use of the Analytic Hierarchy Process for Medication Decision-Making in Type 2 Diabetes

AimTo investigate the feasibility and utility of the Analytic Hierarchy Process (AHP) for medication decision-making in type 2 diabetes.MethodsWe conducted an AHP with nine diabetes experts using structured interviews to rank add-on therapies (to metformin) for type 2 diabetes. During the AHP, participants compared treatment alternatives relative to eight outcomes (hemoglobin A1c-lowering and seven potential harms) and the relative importance of the different outcomes. The AHP model and instrument were pre-tested and pilot-tested prior to use. Results were discussed and an evaluation of the AHP was conducted during a group session. We conducted the quantitative analysis using Expert Choice software with the ideal mode to determine the priority of treatment alternatives.ResultsParticipants judged exenatide to be the best add-on therapy followed by sitagliptin, sulfonylureas, and then pioglitazone. Maximizing benefit was judged 21% more important than minimizing harm. Minimizing severe hypoglycemia was judged to be the most important harm to avoid. Exenatide was the best overall alternative if the importance of minimizing harms was prioritized completely over maximizing benefits. Participants reported that the AHP improved transparency, consistency, and an understanding of others’ perspectives and agreed that the results reflected the views of the group.ConclusionsThe AHP is feasible and useful to make decisions about diabetes medications. Future studies which incorporate stakeholder preferences should evaluate other decision contexts, objectives, and treatments.     

基于水源涵养的流域适宜森林覆盖率研究

适宜森林覆盖率的研究是流域防护林空间布局的基础研究,对流域内防护林林种和林分结构调整有着重要的指导意义。以对土壤饱和蓄水量的贡献大小为依据,人力可控和可测为原则进行流域有林地水源涵养功能评价指标筛选。采用群组AHP法剔除因子间相关性较大的指标,筛选出了地形-土壤因子、林分因子、干扰强度因子共计12个指标;用层次分析法(AHP)计算各指标对土壤饱和蓄水量的权重,以此权重计算各有林地小班水源涵养的等级值以及每个等级对应的面积。以流域历年(40a)最大日降雨量147.2 mm计算流域适宜森林覆盖率。结果表明:林分因子 (0.637)>干扰强度因子(0.258)>地形-土壤因子(0.105),即影响平通河流域有林地水源涵养功能最大的因子是林分因子,其次是干扰度因子;流域基于水源涵养的适宜森林覆盖率为57.09%,变幅为43%-73%。     

A Niche-Based Framework to Assess Current Monitoring of European Forest Birds and Guide Indicator Species' Selection

Concern that European forest biodiversity is depleted and declining has provoked widespread efforts to improve management practices. To gauge the success of these actions, appropriate monitoring of forest ecosystems is paramount. Multi-species indicators are frequently used to assess the state of biodiversity and its response to implemented management, but generally applicable and objective methodologies for species'' selection are lacking. Here we use a niche-based approach, underpinned by coarse quantification of species'' resource use, to objectively select species for inclusion in a pan-European forest bird indicator. We identify both the minimum number of species required to deliver full resource coverage and the most sensitive species'' combination, and explore the trade-off between two key characteristics, sensitivity and redundancy, associated with indicators comprising different numbers of species. We compare our indicator to an existing forest bird indicator selected on the basis of expert opinion and show it is more representative of the wider community. We also present alternative indicators for regional and forest type specific monitoring and show that species'' choice can have a significant impact on the indicator and consequent projections about the state of the biodiversity it represents. Furthermore, by comparing indicator sets drawn from currently monitored species and the full forest bird community, we identify gaps in the coverage of the current monitoring scheme. We believe that adopting this niche-based framework for species'' selection supports the objective development of multi-species indicators and that it has good potential to be extended to a range of habitats and taxa.     

Evaluation of the total petroleum hydrocarbon (TPH) standard for JP‐4 jet fuel

The potential for use of alternatives to total petroleum hydrocarbons (TPH) for remediation purposes was examined specifically for JP‐4 fuel. The study objective was to determine the scientific basis for use of fuel constituents other than TPH in establishing soil cleanup standards at JP‐4‐contaminated sites. The general bases for TPH soil cleanup standards or goals were characterized. Problems with the use of TPH for cleanup included its lack of specificity (e.g., method‐, medium‐, and time‐from‐spill‐dependency) as well as the lack of toxicological relevance. JP‐4 fuel constituents (alkanes, BTEX [i.e., benzene, toluene, ethylbenzene, xylenes], polycyclic aromatic hydrocarbons [PAHs, i.e., chrysene], and naphthalenes) were identified as potential TPH alternatives. A series of criteria were applied to assess the viability of the use of specific JP‐4 constituents as TPH alternatives, and to select the most appropriate alternative. Criteria included chemical fate and transport, toxicity, and regulatory standards for relevant media of concern. Consideration of these criteria ultimately resulted in selection of benzene as the JP‐4 indicator of choice. The potential for altering risk‐based benzene soil cleanup concentrations (preliminary remediation goals, PRGs) was examined, and encompassed the basis for the existing benzene cancer slope factor (SF) as well as the role of distributional analysis of exposure parameters (Monte Carlo) that might be employed at JP‐4 spill sites. Results and conclusions are presented, and the implications for fuels other than JP‐4 are also discussed.     

Modified AHP-based decision-making model toward accurate selection of eligible maintenance media for production of <Emphasis Type="Italic">taxanes</Emphasis> in <Emphasis Type="Italic">Taxus baccata</Emphasis> callus culture

Attempts were made here to apply a modified analytic hierarchy process (AHP) approach based on refinement assay of dominated alternatives in monitoring the most reliable callus maintenance media (supplemented with l-glutamine and Casamino acid) of Taxus baccata callus cultures in terms of five criteria. Generally, regarding stem-derived calli, 6 out of 18 maintenance media were nominated as non-dominated alternatives, and following AHP ranking test Casamino acid-based media (i.e., A12, A15 and A19) were overall nominated as the premiere. Taking leaf-derived calli into account, only l-glutamine-based media in an ascending order of A8, A4, A6, A5, A9 and A3 were introduced as non-dominated alternatives. Such results connote that l-glutamine-based feeding appears to generate more significant results either for continuous calli growth or taxanes production. In contrast, regarding the second explant, stem, both amino acid supplies had fairly equal worth. Our findings, overall, demonstrate promising applications of the proposed AHP method regarding accurate selection of the best callus maintenance cultures of T. baccata for production of different taxanes including paclitaxel, Baccatin III and 10-deacetylbaccatin III. Similarly, this statistical approach could be also applicable for other crops, for instance, for accurate selection of the best callus cultures/media and consequently production improvement of a given plant secondary metabolite/product.     

Shifting pH optimum of Bacillus circulans xylanase based on molecular modeling

Although hydrolases are used in several industrial processes, its industrial applications have some limitations in specific cases since some industrial processes are carried out at pH value which is different from optimum pH of the enzyme. Alkaline side optimum pH of hydrolases is always desirable, and it is proved difficult to achieve that by mutation only. Hence, molecular modeling was applied to select the promising mutants. The changes in electrostatic potential, which was calculated using Delphi, were compared to the changes in pH optimum of four hydolases and their mutants. The results showed that the change in electrostatic potential can be used as an indicator for selecting relevant candidates of mutation. Bacillus circulans xylanase was selected as a model system, and the promising mutants were picked up by the molecular modeling. Q167M and R73V, had a higher pH optimum than the wild type, while K175Q had a similar pH-activity profile of the wild type.     

Developing an ethics-based approach to indicators of sustainable agriculture using analytic hierarchy process (AHP)

This study was conducted to determine the strategies and ethics of sustainability in agriculture and food systems in Iran. To represent the points of view of 57 agricultural stockholders, including an ago-ecologist specialist, agricultural extension and development experts, farmers, and the Iranian Scientific Society of Agroecology (ISSA) members, the analytic hierarchy process (AHP) was employed. A hierarchical network was developed at two levels for selection from among the three ethical approaches, which were developed based on the general tenets of utilitarian, rights, and virtue models. The findings indicated that criteria, i.e. resilience of agricultural systems, supportive policies and self-reliance, and equity, are the most important criteria for sustainable agriculture (SA) in Iran. A sensitivity analysis was carried out to determine the critical factors affecting the priority of alternatives. The results indicated that virtue, rights, and utilitarian models have successive levels of priority as the theoretical base of sustainable agricultural development in Iran. Finally, we outline two strategies for developing a macroethics approach: informational strategies to consider the priorities of virtue model, and structural strategies to highlight the reinforcing nature of right model and utilitarian model.     

Quantitative analysis of flavonol glycosides in Ginkgo biloba: a comparison of two analytical methods

A comparison of testing methods for constituents of Ginkgo biloba was performed as part of the process for determining which of the many available analytical methods was most appropriate for inclusion in the American Herbal Pharmacopoeia (AHP). Three primary methods were reviewed: those adopted by the European Pharmacopoeia, the National Science Foundation-Institute for Nutraceutical Advancement (NSF-INA) and the United States Pharmacopeia. Methods were compared by evaluating sample preparation and hydrolysis, precision and methods of total flavonol glycoside calculation by two independent laboratories. The AHP adopted the method of NSF-INA for inclusion in the AHP monograph owing to observed superiority of this method in terms of precision, glycoside calculation, ease of sample preparation and chromatographic parameters.     

Indicators for optical oxygen sensors

Continuous monitoring of oxygen concentration is of great importance in many different areas of research which range from medical applications to food packaging. In the last three decades, significant progress has been made in the field of optical sensing technology and this review will highlight the one inherent to the development of oxygen indicators. The first section outlines the bioanalytical fields in which optical oxygen sensors have been applied. The second section gives the reader a comprehensive summary of the existing oxygen indicators with a critical highlight on their photophysical and sensing properties. Altogether, this review is meant to give the potential user a guide to select the most suitable oxygen indicator for the particular application of interest.     

Hierarchical Gene Selection and Genetic Fuzzy System for Cancer Microarray Data Classification

This paper introduces a novel approach to gene selection based on a substantial modification of analytic hierarchy process (AHP). The modified AHP systematically integrates outcomes of individual filter methods to select the most informative genes for microarray classification. Five individual ranking methods including t-test, entropy, receiver operating characteristic (ROC) curve, Wilcoxon and signal to noise ratio are employed to rank genes. These ranked genes are then considered as inputs for the modified AHP. Additionally, a method that uses fuzzy standard additive model (FSAM) for cancer classification based on genes selected by AHP is also proposed in this paper. Traditional FSAM learning is a hybrid process comprising unsupervised structure learning and supervised parameter tuning. Genetic algorithm (GA) is incorporated in-between unsupervised and supervised training to optimize the number of fuzzy rules. The integration of GA enables FSAM to deal with the high-dimensional-low-sample nature of microarray data and thus enhance the efficiency of the classification. Experiments are carried out on numerous microarray datasets. Results demonstrate the performance dominance of the AHP-based gene selection against the single ranking methods. Furthermore, the combination of AHP-FSAM shows a great accuracy in microarray data classification compared to various competing classifiers. The proposed approach therefore is useful for medical practitioners and clinicians as a decision support system that can be implemented in the real medical practice.     

数据点选择与参数估计方法对杉木人工林自疏边界线的影响

自疏边界线是指植物种群发生密度依赖死亡时种群最大收获量的上边界线。已有研究由于在拟合自疏边界线的过程中对数据点的选择和参数估计的方法存在诸多的差异,进而导致产生对自疏法则的争议。该研究采用26年生杉木(Cunninghamia lanceolata)人工林的定位观测数据,对视觉法、死亡率法、等距区间法和相对密度法等4种数据点选择方法以及最小二乘法、降维分析法、分位数回归法和随机边界方程等4种参数拟合方法进行对比分析,以探寻客观选择自疏拟合数据和正确拟合方法的途径。比较4种不同的数据选择方法得出:视觉法具有较强的主观性;对于没有发生非密度依赖死亡的林分,死亡率法可以准确地确定林分自疏的起始点;等距区间法可以减少非密度依赖死亡的影响,得到的数据点能充分反映林分的自疏过程;相对密度法可以保证临界密度阈值以上的数据点拟合林分自疏边界线的有效性,并能排除非密度依赖死亡的影响。比较分析4种不同的拟合方法发现:最小二乘法和降维分析法拟合的林分自疏边界线均从实测数据"中心"穿过,与林分自疏边界线为林分收获量上边界线的涵义不相符合,无法真实反映林分的自疏进程;分位数回归和随机边界方程的拟合结果均与实测数据一致,能够较为准确地反映林分自疏的真实过程,但二者的统计推断要求都比较严格。分位数值的正确选取和残差足够小且趋于0,是分位数回归法和随机边界方程能否正确反映林分自疏动态的前提。     

Combining local ecological knowledge and quantitative forest surveys to select indicator species for forest condition monitoring in central Viet Nam

In tropical central Viet Nam, as part of a forest allocation program, forest condition should be monitored by local stakeholders. If local ecological knowledge can be integrated into the development of indicator species, then improvements in both the rigor of the indicator list and the involvement of local people in the monitoring process may occur. We used a dual methodology to derive two forest condition indicator species lists using trees, based on local ecological knowledge and quantitative forest surveys. Combining these lists allowed us to produce a final list of thirteen ‘probable’ and eight ‘possible’ indicator tree species for forest condition monitoring. Despite some possible limitations to the methodology, we encourage the use of multiple data sets when working with rural communities that are involved in the monitoring process. Local people can propose timely and appropriate measures of forest conservation and improvement, and can definitely integrate indicator species into monitoring community forests.     

Nitrous oxide monitoring for nitrifying activated sludge aeration control: a simulation study

An activated sludge aeration control concept was developed utilizing off-gas nitrous oxide concentrations as a surrogate for autotrophic nitrifying bacterial inhibition and aeration air as a master control variable. The control concept was evaluated using a simulated pilot scale bioreactor (mathematically calibrated liquid phase process model and a model to link off-gas nitrous oxide generation to liquid phase conditions) as a data generator. When applied to the simulated system, the process controller was successful at maintaining the process at the desired operating setpoint and promoting stable operation by minimizing periods of significant inhibition. Furthermore, it provided a more efficient use of the air supplied to the bioreactor during periods of varying feed loading by matching the air supply to the metabolic demands, substantially reducing periods of over and under-aeration. The findings of this research demonstrate the potential for off-gas nitrous oxide monitoring as a completely non-invasive alternative to liquid phase monitoring used in conventional dissolved oxygen control. Investigations are currently underway at the laboratory scale to evaluate the benefits and limitations associated with this control concept, with particular emphasis on implementation issues and the quantification of potential aeration and cost savings.     

An Integrated Approach of Fuzzy Linguistic Preference Based AHP and Fuzzy COPRAS for Machine Tool Evaluation

Globalization of business and competitiveness in manufacturing has forced companies to improve their manufacturing facilities to respond to market requirements. Machine tool evaluation involves an essential decision using imprecise and vague information, and plays a major role to improve the productivity and flexibility in manufacturing. The aim of this study is to present an integrated approach for decision-making in machine tool selection. This paper is focused on the integration of a consistent fuzzy AHP (Analytic Hierarchy Process) and a fuzzy COmplex PRoportional ASsessment (COPRAS) for multi-attribute decision-making in selecting the most suitable machine tool. In this method, the fuzzy linguistic reference relation is integrated into AHP to handle the imprecise and vague information, and to simplify the data collection for the pair-wise comparison matrix of the AHP which determines the weights of attributes. The output of the fuzzy AHP is imported into the fuzzy COPRAS method for ranking alternatives through the closeness coefficient. Presentation of the proposed model application is provided by a numerical example based on the collection of data by questionnaire and from the literature. The results highlight the integration of the improved fuzzy AHP and the fuzzy COPRAS as a precise tool and provide effective multi-attribute decision-making for evaluating the machine tool in the uncertain environment.     

Developing indicators for adaptation decision-making under climate change in agriculture: A proposed evaluation model

This study proposes a new approach to developing a set of indicators for evaluating, prioritizing and choosing adaptation practices to climate change in agriculture. A simulation process is further conducted by applying the proposed indicators and the AHP model to prioritize adaptation alternatives to drought conditions. Data are collected through semi-structured questionnaires, focus group discussions, face- to-face interviews and literature review. Based on the focus group discussions, a six-step process is derived for use in developing indicators. A total of seventeen indictors are developed and classified into two broad components; feasibility and effectiveness (eight and nine indicators, respectively). The simulation results show that irrigation and drought- tolerant varieties are most feasible and effective alternative adaptation practices to drought in the Lawra district of Ghana. The proposed indicators are expected to provide a useful tool for supporting the decision-making process of stakeholders in the agriculture sector under climate change conditions.