A Two-Stage Scenario-Based Robust Optimization Model and a Column-Row Generation Method for Integrated Aircraft Maintenance-Routing and Crew Rostering

Motivated by a critical issue of airline planning process,this paper addresses a new two-stage scenario-based robust optimization in operational airline planning to cope with uncertainty and possible flight disruptions.Following the route network scheme and generated flight timetables,aircraft maintenance routing and crew scheduling are critical factors in airline planning and operations cost management.This study considers the simultaneous assignment of aircraft fleet and crew to the scheduled flight while satisfying a set of operational constraints,rules,and regulations.Considering multiple locations for airline maintenance and crew bases,we solve the problem of integrated Aircraft Maintenance Routing and Crew Rostering(AMRCR)to achieve the minimum airline cost.One real challenge to the efficiency of the planning results is the possible disruptions in the initial scheduled flights.Due to the fact that disruption scenarios are expressed discretely with a specified probability,and we provide adjustable decisions under disruption to deal with this disruption risk,we provide a Two-Stage Scenario-Based Robust Optimization(TSRO)model.In this model,here-and-now or first-stage variables are the initial resource assignment.Furthermore,to adapt itself to different disruption scenarios,the model considers some adjustable variables,such as the decision to cancel the flight in case of disruption,as wait-and-see or second-stage variables.Considering the complexity of integrated models,and the scenario-based decomposable structure of the TRSO model to solve it with better computational performance,we apply the column and row generation(CRG)method that iteratively considers the disruption scenarios.The numerical results confirm the applicability of the proposed TSRO model in providing the AMRCR problem with an integrated and robust solution with an acceptable level of computational tractability.To evaluate the proposed TSRO model,which solves the AMRCR problem in an integrated and robust manner,five Key Performance Indicators(KPIs)like Number of delayed/canceled flights,Average delay time,and Average profit are taken into account.As key results driven by conducting a case study,we show the proposed TSRO model has substantially improved the solutions at all indicators compared with those of the sequential/non-integrated and nominal/non-robust models.The simulated instances used to assess the performance of the proposed model and CRG method reveal that both CPLEX and the CRG method exhibit comparable and nearly optimal performance for small-scale problems.However,for large-scale instances the proposed TSRO model falls short in terms of computational efficiency.Conversely,the proposed CRG method is capable of significantly reducing computational time and the optimality gap to an acceptable level.

Scientific and technical aspects of yogurt fortification:A review

Food fortification is one of the most important processes for improvement of the nutrients quality and quantity in food.It can be a very cost effective public health intervention.Due to the high consumption rate of dairy products such as yogurt,fortification of these products will effectively reduce or prevent diseases associated with nutritional deficiencies.The aim of this investigation is to study the technical aspects involved in production of different types of fortified yogurts and their role in disease prevention and correction of deficiencies.In this paper,firstly,fortification is defined and the main reasons behind carrying out this process are presented and then yogurt production process and a variety of minerals,vitamins,and functional ingredients which are used in the process are briefly discussed.©2015 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

Planning and Implementing Food Fortification Programs to Combat Micronutrient Malnutrition: Iron

Iron deficiency anemia is the most prevalent nutritional deficiency in the world and food fortification is a cost-effective approach to combat it. This paper reviews the food fortification process with micronutrients, with special emphasis on iron and the most critical steps and common difficulties found when implementing a program. The first step is to measure the magnitude of the problem and the groups affected by iron deficiency and anemia, to determine if there is a need for fortification. Then the adequate iron compound and vehicle should be selected, to obtain a bioavailable form of iron in a frequently consumed food item without changing the taste, appearance or cooking characteristics of the final food item or complete meals containing it, to assure the acceptance by consumers. Before implementation, bioavailability studies are in order for the fortified food item and for complete meals especially typical or traditional meals, followed by field studies and pilot tests. Once implemented, the program should be monitored and evaluated continuously, and the impact on health assessed periodically to give the program the flexibility for continuation made changes or finalization when necessary. Other key elements for successful implementation of food fortification programs include the presence of a viable food industry;available channels for food marketing and distribution;a health care system to identify and monitor micronutrient malnutrition in the population;institutions for education, treatment and evaluation of the impact of the program;and continuous and effective input into the planning, implementation, monitoring and evaluation of the intervention to ensure sustainability of the intervention.

The Introduction of European Fortification in the Late Ming Period

In the late Ming period,Xu Guangqi and other Catholic literati were actively involved with military affairs because of the invasion of the Manchu forces and the threat of uprisings.The story of how they imported European cannons and gunners from Macao is now quite famous.However,the introduction of European fortifications,mainly the trace Italienne,in the same period is still relatively unknown.Xu Guangqi and his student Sun Yuanhua exerted considerable efforts in advocating European-style bastions.Xu not only received help from Jesuits,but also support from some Fujianese who were familiar with Intramuros,the Spanish walled city of Manila.In addition to Xu and Sun,Han Lin and Han Yun(also Xu’s students)prepared a Chinese treatise on European fortification architecture based on Italian sources and tried to put the knowledge into practice.Another relevant figure is Ma Weicheng,who allegedly directed the building of 32 angled bastions in three cities around 1640.Although a few recorded writings and practices of constructing European-style fortification appeared in the first half of the seventeenth century,soon afterwards the art of trace Italienne met its end prematurely in China.To a great extent,the swift collapse of the Ming dynasty eliminated the possibility of spreading the new defense technology.Throughout the eighteenth century,the Qing dynasty enjoyed long-term peace,and the warfare at the frontiers brought few threats to the city walls.There was thus little urgency to develop innovative defensive works and European fortification sunk into oblivion until the mid-nineteenth century.

Scenario-based approach for project portfolio selection in army engineering and manufacturing development

The decisions concerning portfolio selection for army engineering and manufacturing development projects determine the benefit of those projects to the country concerned.Projects are typically selected based on ex ante estimates of future return values,which are usually difficult to specify or only generated after project launch.A scenario-based approach is presented here to address the problem of selecting a project portfolio under incomplete scenario information and interdependency constraints.In the first stage,the relevant dominance concepts of scenario analysis are studied to handle the incomplete information.Then,a scenario-based programming approach is proposed to handle the interdependencies to obtain the projects,whose return values are multi-criteria with interval data.Finally,an illustrative example of army engineering and manufacturing development shows the feasibility and advantages of the scenario-based multi-objective programming approach.

Research on the seismic fortification level of offshore platform in Bohai Sea and adjacent areas

API code is introduced at first, and then a comparison of seismic character and seismic hazard between Bohai and Southern California is carried out. The analysis indicates both the seismic frequency and intensity and the seismic hazard of Bohai are much weaker than that of Southern California. API code states the strength level and deformation level of permanent structures in Southern California takes 200 a and several hundred to a few thousand years respectively. But in the reference codes in China, the seismic levels take 500 a and 10000 a for strength design and deformation design, and it seems too conservative. In China, the deformation level of class A structure takes 2%-3% probabilities of exceedance in reference period 100 a, and that of class B and C often takes 2%-3% in 50 a. Now that offshore platforms may cause server subsequent risk, it is safe to take 1% in 30 a as its deformation design level. On the basis of the above analyses and social economic level and the consistency with present codes, the strength design level and deformation design level of Chinese offshore platforms is suggested to take 200 a and 3000 a respectively.

Protein Fortification of Corn <i>Tortillas</i>: Effects on Physicochemical Characteristics, Nutritional Value and Acceptance

The aim of this study was to evaluate the texture of corn dough as well as the nutritional quality and acceptance of corn cakes (tortillas) made either with a readymade commercial corn flour (CCF) or with a traditional way (nixtamal) both fortified with lys + tryp (L + T) or with a protein concentrate from Phaseolus lunatus added with L + T (PC + L + T). All treatments were analyzed to investigate the physical properties of the dough and tortillas as well as their physicochemical and nutritional quality. Results showed that cohesion was affected (p tortillas made with nixtamal showed no difference. Adhesion was not affected by treatments. Weight loss increased only in the fortified tortillas made with CCF (p tortillas increased with the fortification being the highest value 0.96 N. Color was not affected in tortillas made with CCF (p tortillas made with CCF and fortified with PC + L + T. Acceptance was greater for tortillas fortified with L+T alone. Protein fortification of tortillas made with either CCF or nixtamal is feasible using either L + T together or in combination with a PC from Phaseolus lunatus improving their nutritional value without negative effects on their physicochemical characteristics or acceptance.

Large, moderate, small earthquakes and seismic fortification criterion

This paper discusses the relation between two-step seismic design and the standard of probability of exceedance, and the relation of three-levels seismic ground motion parameters given by probability method and comprehensive probability method. The relative size relations of the ground motions with 2%, 10%, 63% probability of exceedance in 50 years, namely large earthquake, moderate earthquake, and small earthquake, are discussed through a practical example of seismic hazard analysis. The methods to determine seismic fortification criterion are discussed.

Optimization of Bioactive Fortification in Apple Snacks through Vacuum Impregnation Using Response Surface Methodology

Fortification of apple slices with t-resveratrol glucoside was obtained by vacuum impregnation (VI) of apple slices with a solution containing grape juice using response surface methodology (RSM). Three independent variables of the VI process: vacuum pressure, application time and relaxation time, were coded at five levels in a central composite design. The VI-treated and dried apple slices were analyzed for t-resveratrol glucoside concentration and textural attributes (gradient and linear distance). Multiple response optimization revealed the following optimum VI condi-tions for the bioactive enrichment and improved textural quality of dried apple slices: vacuum pressure of 6 in. of Hg, application time of 10 min, and relaxation time of 22.5 min.

A knowledge-to-action approach to food fortification: Guiding principles for the design of fortification programs as a means of effectively addressing micronutrient malnutrition

The gap that exists between research and the dissemination and implementation of research findings has been well established. Food fortification, one of the most cost-effective means of addressing micronutrient malnutrition, is no exception. With decades of implementation experience, there is need to strengthen mechanisms that effectively broadcast proven strategies to promote the successful implementation of fortification programs in changing, challenging, and dynamic environments. This requires clear channels of communication, well-defined in-country leadership, and a streamlined and focused approach that can be adapted to country-specific contexts. Based on experience designing and implementing fortification programs throughout Africa and a broad understanding of past successes and failures, a model is proposed that articulates often over-looked program elements critical to design and implementation.

Iodine and Selenium Intake in a Sample of Women of Childbearing Age in Palmerston North, New Zealand after Mandatory Fortification of Bread with Iodised Salt

Iodine deficiency is a worldwide public health problem, which has long been observed in many parts of the world, including New Zealand (NZ). The aim of this study was to assess iodine and selenium intake among women of childbearing age in Palmerston North, New Zealand post mandatory fortification of bread with iodised salt. Fifty women of childbearing age completed a researcher-led questionnaire, including a semi-quantitative food frequency questionnaire. Iodine and selenium were analysed in 24-hour urine samples. The median urinary iodine concentration (UIC) was 65 μg/l with 30% below 50 μg/l;representing mild iodine deficiency according to the World Health Organization. The estimated median daily iodine intake (130 μg/day) was higher than the Estimated Average Requirement (100 μg/day) and higher than seen in women prior to fortification. The median excretion of selenium (32 μg/day) was slightly above level suggested as adequate (30 μg/day) and estimated median intake (57 μg/day) was higher than Estimated Average Requirement (50 μg/day). Selenium and iodine excretion were significantly correlated (Spearman’s rank order;r(50) = 0.547, p 0.001). The major contributors to iodine intake were milk (36%), bread (25%) and fish/seafood (15%). Participants had a mean intake of 2.5 slices of bread/day, which contributed approximately 14 to 20 μg of iodine. The majority of participants (74%) had iodised salt at home, but less than half (48%) used iodised salt exclusively. In conclusion, despite the mandatory fortification of bread with iodised salt in NZ, UIC of the study population indicates iodine deficiency although their estimated dietary intakes appear adequate. It is essential that government initiatives to improve iodine status are evaluated for their efficacy.

Scenario-based Participatory Design for Pervasive Computing

Lots of pervasive computing researchers are working on how to realize the user-centered intelligent pervasive computing environment as Mark Weiser figured out.Task abstraction is the fundamentation of configuration for pervasive application.Based on task-oriented and descriptive properties of scenario,a scenario-based participatory design model was proposed to realize the task abstraction.The design model provided users and domain experts a useful mechanism to build the customized applications by separating system model into domain model and design model.In this design model,domain experts,together with users,stakeholders focus on the logic rules(domain model)and programmers work on the implementation(design model).In order to formalize the model description,a human-agent interaction language to transform users' goals and domain rules into executable scenarios was also discussed.An agent platform-describer used to link design and implementation of scenarios was developed to realize the configuration of applications according to different requirements.The demand bus application showed the design process and the usability of this model.

Storming Fortifications

Feel for boulders while crossing the river. ---Deng Xiaoping After a 20-year track record of extraordinary successes, however, China’sleaders now confront the toughest issues since reforms began in 1978. The domes-tic economic growth rate is declining, and the surrounding region is confronting

Lectotype optimization of mid-highrise residential building based on site conditions and seismic fortification intensity

A multi-objective lectotype optimization model based on site conditions and seismic fortification intensity is presented for mid-highrise residential buildings taking into account multiple items such as the original investment, disaster losses and maintenance cost, the integral stiffness, the total ductility, the construction period, and so on. A Three-Scale Fuzzy Analytical Hierarchy process is proposed by introducing the Three-Scale Analytical Hierarchy process and the trapezoid fuzzy number. The result of a calculation example shows that the T-FAHP is practical.

The Planned Conservation of the Urban Fortifications of Tuscany: Satellite Interferometry as an Innovative Monitoring Technology for Asset Management

The “Monitoring City Walls” research project by the University of Pisa approaches planned conservation as a process that pursues an in-depth understanding of historic city walls and their surroundings to define a system of effective risk prevention. This multidisciplinary research adopts monitoring strategies and technologies at the large scale and in relationship to natural and urban conditions. The underlying logic frames the conservation of these historic fortifications within the more general mitigation of risks generated by context. The research aims to develop an innovative approach to monitoring ancient defensive structures in historical towns. The integrated use of advanced technologies allows for the control and, most importantly, advance identification of possible risks. These new technologies, in particular satellite interferometry, make it possible to improve and increase the operational capacity of monitoring processes by facilitating the acquisition and investigation of data relative to the system defined by ancient city walls and their surroundings. These technologies also represent a cost-effective tool for managing the important transition from the observation and study of individual monuments to the monitoring of large monumental complexes or even entire historical centers.

Study on the Seismic Fortification Criteria of Offshore Platforms in the Bohai Sea

This paper analyzes the seismicity and seismic risk distribution in the Bohai Sea. Based on the seismic design parameters of 46 platforms in the Bohai Sea, a statistic analysis is made on the ratios of the peak accelerations for different probability levels. In accordance with the two-stage design method, a scheme of two design seismic levels is proposed, and two fortification goals are established respectively for strength level earthquakes and ductility level earthquakes. Through analogy and comparison to the Chinese seismic code for buildings, it is proposed that the probability level for the strength and ductility level earthquakes takes return periods of 200a and 1000～2500a respectively, and we further expounded on its rationality. Finally, the fortification parameters in the sub-regions of Bohai Sea area are given in the light of seismic risk zonation and ground motion division. This article is a summary of experiences from many years of offshore platform seismic fortification work, and an exploratory study on the seismic fortification standards of offshore platforms in China, which may provide some references for the establishment of the standard.

Study on the Relationship of Seismic Design Ground Motion at Different Fortification Levels in the Xinjiang Region

The seismic risk analysis results of 79 cities in Xinjiang are presented, and the bedrock peak ground accelerations under three seismic levels and their ratios are discussed. Then, the relationship between earthquake environments and the seismic risk analysis results of different exceeding probabilities are researched. The results show that minor and major earthquake motion parameters calculated from moderate earthquakes do not have a consistent probability and the ratio of bedrock peak accelerations under different exceedance probabilities are dosdy correlated with earthquake environments.

A Comparison of Domestic and Foreign Seismic Fortification Standards for Electrical Equipment

It is of great significance to make comparative analyses of seismic fortification criteria at home and abroad for improving the anti-seismic capability of electrical equipment and revising the relevant national standards.A brief overview of American,Japanese,IEC standards and Chinese seismic design codes for electrical equipment is presented.Differences between these seismic fortification standards of electrical equipment are compared and analyzed in respect of the goal and level of seismic fortification and the seismic design spectrum.The advantages and disadvantages of Chinese standards are pointed out.Through learning from foreign experience on the determination of seismic fortification standards,recommendations are made for the improvement and revision of Chinese seismic fortification standards for electrical equipment.

某线震后轨道设计方案研究

2022年1月8日门源发生6.9级地震,造成某线隧道二衬坍塌、桥梁梁体移位、接触网脱落等基础、设备严重损坏,并伴随钢轨折断、扣件脱落、道床倾斜等轨道震害,是我国高速铁路首次遭遇的强震作用下严重受灾事件。结合震后预测余滑变形量水平150~300 mm,垂向100 mm条件下,在设防区段提出一种“三孔连体套管承轨台可调式WJ-8型扣件+长枕埋入式单层道床预留切割孔”新型大调整量无砟轨道结构方案。其中,三孔连体套管承轨台可调式WJ-8型扣件在既有WJ-8型扣件基础上通过增设铁承轨台、调距块和三联套管等部件可满足单股钢轨左右位置调整量达152 mm,长枕埋入式单层道床中预留切割孔,便于在基础变形超出扣件调整范围后切割纠偏;通过对余滑变形后线路拟合获得拨距包络图,确定了大调整量无砟轨道铺设范围。

乌兹别克斯坦9度区某超高层建筑结构设计与优化

对于9度设防地区的超高层建筑,其结构设计基本由地震作用控制,因此抗震设计尤为重要。建筑消能减震技术可在提高结构地震安全储备的同时,降低整体工程造价,是结构优化设计的有效措施。对位于9度区的超高层建筑进行了结构方案选型对比、结构方案优化、减震设计方案比选、剪力墙内嵌钢板优化。结果显示,钢骨混凝土框架⁃核心筒方案相对于钢框架⁃支撑方案具备更高的成本优势;框架⁃核心筒方案可通过精细化设计作进一步优化;在此基础上,对钢骨混凝土框架⁃核心筒方案采用两种消能减震方案进行比选,结果表明,采用黏滞阻尼器方案的结构抗震性能明显优于采用黏滞阻尼墙方案;最后通过增大剪力墙竖向分布钢筋配筋率,对低区核心筒墙肢中的内嵌钢板进行了优化。