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This paper addresses a problem of ship type decision considering empty container repositioning and foldable containers, which determines the capacity of ships deployed in a given shipping route at a tactical level and empty container repositioning between ports at an operational level. It considers the use of foldable containers and aims to find under what conditions, a shipping liner needs to use the foldable containers. To solve the problem, we formulate a network flow model with a revised network simplex algorithm, based on which an exact solution approach is designed to determine the optimal ship type.

This study investigates an optimal control policy for a liner ship to decide at which ports and how much fuel the liner ship should be refueled under stochastic fuel consumption in each leg and stochastic fuel price at each port. Based on some properties proved in this study, a dynamic programming algorithm is then designed to obtain some important threshold values, which are used in the optimal control policy for ship refueling decision. Extensive experiments show that the proposed method can obtain the optimal decision within a reasonable time (about 170 s) for various scales of problem instances (up to 30 ports) as well as various settings of probability distributions. In addition, some comparative experiments also show that the proposed optimal decision policy can save at least 8% fuel consumption cost by comparing with some relatively simple rules and save about 1% cost on average by comparing with some brilliantly-designed rules.

Refrigerator cars are widely used for fresh product distribution. The energy consumption of these vehicles is sensitive to the environment temperature, and changes continuously due to fluctuations of the environment temperature. As a result, the total refrigeration cost is influenced by the car’s departure time. To reduce operation costs of third-party transportation providers, the refrigerator car scheduling problem is addressed in this research. A time-dependent mixed-integer programming model is established to reduce total operation costs, including routing, time penalty, cargo damage and refrigeration costs. An adaptive heuristic method is proposed by combining the variable neighbourhood search and particle swarm optimisation. To improve the algorithm quality, a two-stage decomposition method is developed. The problem is divided into two echelon sub-problems. One is the shortest path problem, and the other is the departure time scheduling problem. A feedback strategy is utilised to avoid local optimal...

© 2016 Elsevier Ltd This paper addresses a decision problem on planning cruise services for a cruise ship so as to maximize the total profit during a planning horizon. The service is a sequence of ports (harbor cities) that the cruise ship visits. In this decision problem, the constraint about the availability of berths at each port is taken into account. In reality, if a cruise service is executed by the ship repeatedly for several times, the profit earned by the cruise service in each time decreases gradually. This effect of decreasing marginal profit is also considered in this study. We propose a nonlinear integer programming model to cater to the concavity of the function for the profit of operating a cruise service repeatedly. To solve the nonlinear model, two linearization methods are developed, one of which takes advantage of the concavity for a tailored linearization. Some properties of the problem are also investigated and proved by using the dynamic programming (DP) and two commonly used heuristics. In particular, we prove that if there is only one candidate cruise service, a greedy algorithm can derive the optimal solution. Numerical experiments are conducted to validate the effectiveness of the proposed models and the efficiency of the proposed linearization methods. In case some parameters needed by the model are estimated inexactly, the proposed decision model demonstrates its robustness and can still obtain a near-optimal plan, which is verified by experiments based on extensive real cases.

This study extends a problem on locating distribution centers under uncertainty.The decision on facility size is considered.This study is oriented to multiple period decision contexts.A mixed-integer programming model as well as lower, upper bounds are developed. This study extends a traditional problem on locating distribution centers (DC) under uncertain demands, and proposes a stochastic programming model on locating DCs, determining their suitable scales, as well as adjusting DCs so as to adapt to the dynamically changing demands at the sites of retailers. Some lower and upper bounds are also designed to analyze the values of the perfect information, stochastic solution, and the DC adjustments. Numerical experiments are conducted to validate the effectiveness of the proposed model.

This paper is about yard management in container ports. As a tactical level decision-making tool in a port, a yard template determines the assignment of spaces (subblocks) in a yard for arriving vessels, which visit the port periodically. The objective of yard template planning is to minimize the transportation cost of moving containers around the yard. To handle yard template planning, a mixed integer programming model is proposed that also takes into account traffic congestion in the yard. A further complication is that the cycle time of the vessels' periodicities is not uniform and varies among them, perhaps being one week, ten days, or two weeks, etc. However, this multiple cycle time of the periodicities of vessel arrival patterns, which complicates the yard template decision, is also considered in the model. Moreover, a local branching based solution method and a Particle Swarm Optimization based solution method are developed for solving the model. Numerical experiments are also conducted to validate the effectiveness of the proposed model, which can save around 24% of the transportation costs of yard trucks when compared with the commonly used First-Come-First-Served decision rule. Moreover, the proposed solution methods can not only solve the proposed model within a reasonable time, but also obtain near-optimal results with about 0.1–2% relative gap.

For large multinational companies, the complex production process of their finished goods usually contains plenty of stages, which constitute a production flow network. Each production stage in the production flow network can be undertaken by one or more suppliers. This study proposes a stochastic programming model for the production flow network oriented supply chain network design problem, which optimizes the decision of allocating stages to suppliers with the objective of minimizing the total expected costs of production and transportation among suppliers under uncertain demands of customers. A local branching based solution method is developed to solve the model. A case study on applying this model to a large automobile company is performed. In addition, some numerical experiments are conducted to validate the effectiveness of the proposed model and the efficiency of the proposed solution method.

The influences of triethanolamine (TEA) on the portlandite in hardened cement pastes (HCPs) were systematically investigated. Results show that the addition of TEA in cement pastes leads to a visible reduction of Ca(OH)2 (CH) content and considerably alters the morphology of CH crystals from large and parallel-stacked lamellar shape to smaller and distorted actinomorphic one. For the first time, the CH micro-crystals and even non-crystalline CH in HCPs were observed in the presence of TEA. Due to integration of CH micro-crystals in C–S–H phase, remarkable higher Ca/Si ratio of C–S–H phase was found. The formation of TEA-Ca2 + complex via the interaction between Ca2 + and the oxygen atoms in TEA molecule was evidenced by the results of NMR and UV. It is believed that TEA can be introduced into the crystallization process of portlandite and thus significantly alters the morphology of CH crystals and even the content of the crystalline CH phase.

As a tactical-level plan, a yard template determines the assignment of spaces in a container port yard for arriving vessels. This paper investigates the concept of yard congestion quantitatively in the context of yard truck interruptions, and develops a combination of probabilistic and physics-based models for truck interruptions. The above work enables us to exactly evaluate the expected link travel time, which then acts as the basis for proposing a mixed-integer programming model that minimizes the total expected travel time of moving containers around the yard. A Squeaky Wheel Optimization based meta-heuristic is developed to solve the model. Experiments are also conducted to validate the effectiveness of the model and the solution method.

© 2017 "IISE". The Cruise Itinerary Schedule Design (CISD) problem determines the optimal sequence of a given set of ports of call (a port of call is an intermediate stop in a cruise itinerary) and the arrival and departure times at each port of call in order to maximize the monetary value of the utility at ports of call minus the fuel cost. To solve this problem, in view of the practical observations that most cruise itineraries do not have many ports of call, we first enumerate all sequences of ports of call and then optimize the arrival and departure times at each port of call by developing a dynamic programming approach. To improve the computational efficiency,we propose effective bounds on the monetary value of each sequence of ports of call, eliminating non-optimal sequences without invoking the dynamic programming algorithm. Extensive computational experiments are conducted and the results showthat, first, using the bounds on the profit of each sequence of ports of call considerably improves the computational efficiency; second, the total profit of the cruise itinerary is sensitive to the fuel price and hence an accurate estimation of the fuel price is highly desirable; third, the optimal sequence of ports of call is not necessarily the sequencewith the shortest voyage distance, especially when the ports do not have a natural geographic sequence.

A yard template determines the assignment of spaces in a yard for arriving vessels. Fluctuation of demand for freight transportation brings new challenges for making a robust yard template when facing uncertain maritime market. A model is proposed for yard template planning considering random numbers of containers that will be loaded onto vessels that visit the port periodically. Traffic congestions and multiple schedule cycle times for vessel arrival patterns are also considered. Moreover, a meta-heuristic method is developed for solving the model in large-scale cases. Numerical experiments are conducted to validate effectiveness and efficiency of the model.

In engineering design, the decision to select an optimal material for a particular product is a problem requiring multi-criteria decision analysis that involves both qualitative and quantitative factors. The evaluation of alternative materials may be based on imprecise information or uncertain data. Furthermore, there can be significant dependence and feedbacks between the different criteria for material selection. However, most existing decision approaches cannot capture these complex interrelationships. In response, this paper proposes a general framework for evaluating and selecting the best material for a given application. A novel hybrid multiple criteria decision making (MCDM) model combining DEMATEL-based ANP (DANP) and modified VIKOR is used to solve the material selection problems of multiple dimensions and criteria that are interdependent. Moreover, target-based criteria as well as cost and benefit criteria can be addressed simultaneously in the proposed model. Finally, an empirical case concerning the bush material selection for a split journal bearing is presented to illustrate the potential of the new model. The results show that the proposed method for material selection is effective and provides meaningful implications for designers and engineers to refer.

This paper studies ambulance deployment and relocation problems, which are two of the core decisions faced by emergency medical service control centers in metropolis. The challenge in the problems is to estimate the operational performance of a deployment plan under stochastic environments. More specifically, the stochastic and dynamic nature of request arrivals, fulfillment processes, and complex traffic conditions as well as the time-dependent spatial patterns of some parameters complicate the decisions in the problems. This paper proposes a simulation optimization method that enables evaluating the operational performance of deployment plans through a detailed simulation model. For guiding the search process in the simulation optimization method, the genetic algorithm is employed in this study. On the basis of the deployment decisions, a mathematical model on ambulance relocation is also proposed for adapting to the dynamic changing environments along the time. To illustrate the proposed method’s usage in practice, a demo example about its application in Shanghai is given. Some numerical experiments are also performed to validate the effectiveness and the efficiency of the proposed methods.

With advancements of quay side equipments and technologies, the bottleneck of port operations has moved from quay side to yard side. The yard management of a port has significant influences on the competitiveness of a port in the global shipping network. The research area of yard management has attracted a lot of attentions from both the academia and the industrial practitioners. This paper gives a comprehensive review for the studies on the yard management in container terminals. From three aspects, i.e., yard cranes management, yard vehicles management, and yard spaces management, this paper reports the advances in these three areas. Some future directions on the yard management researches are also discussed. The purpose of this paper is to stimulate more practically relevant researches in this emerging area.

To study what and how factors impact on inter-organizational and inter-divisional collaboration in construction projects, a management collaboration model was established, and eight indicators of the model were figured out. A questionnaire including 20 questions designed and delivered to 488 participants from 85 projects, the data of samples analyzed and the correlation of variables calculated by multivariate software named R. Results show that 92.70 percent of respondents suggest that the different project objectives, the different organizational culture and the poor information exchange and communication are the core factors leading to conflict between the participant organizations. Multivariate statistical analysis results show that greater inter-divisional collaboration, more harmonious interpersonal relationship, slighter sense of hierarchy, stronger orientation of democratic management style, and better information exchange and communication can generate less conflicts and better inter-organizational collaboration.

A state-of-the-art review of the seismic response of utility tunnels is presented. The objectives of the review are to present a view of current state of utility tunnel and to examine trends in the future. The review includes: the theoretical analysis, numerical simulation and experimental research on the utility tunnel under earthquake wave excitation. Based on the review, the future scope of work on the subject is outlined.

As a new effort, combined reactive sintering with hot pressing technique, the Ti-22Al-25Nb alloy was successful prepared with element mixed powders. Meanwhile, the reactive sintering was divided into two temperature ranges, which were at 873 K and 1373 K, respectively. The starting sintering kept 1h at 873K, and then the temperature was increased to 1373K, keeping 2h. The orthorhombic (Ti2AlNb) phase was observed in this sintered alloy. Moreover, the homogenization treat was conducted at 1473 K for 2h after the final sintering was accomplished, and the fraction of the orthorhombic phase increased significantly. The microstructures and the phases were analyzed. And the generation mechanism of the orthorhombic phase was also analyzed.

The performance of a wafer fabrication system is constrained by its bottlenecks, which is often affected by the system fluctuations and unpredicted events, e.g., machine breakdown. Considering the re-entrant process flow in wafer fabrication, we propose a scheduling method that divides the process flow into several stages and protects the bottleneck step at each re-entrant stage from the system fluctuations. Furthermore, due to the multiple bottlenecks in wafer fabrication system, we identify the bottlenecks by sensitivity analysis on machines’ capacity. Then, during the real-time scheduling, the bottlenecks with stronger constraints are assigned with higher priority than the bottlenecks with weaker constraints. Finally, a set of simulation experiments are performed to validate the effectiveness of the proposed method.

Berth allocation is an important port operation problem for container terminals. This paper studies how to develop a robust schedule for berth allocation that incorporates a degree of anticipation of uncertainty (e.g., vessels' arrival time and operation time) during the schedule's execution. This study proposes a bi-objective optimization model for minimizing cost and maximizing robustness of schedules. A heuristic is also developed for solving the bi-objective model in large-scale problem cases. Numerical experiments are conducted to validate the effectiveness and efficiency of the proposed model and method. Managerial implications are also discussed.

According to the stitching structure of CCDs in an Aerial Push-broom Remote-sensing Camera(APRC),an auto-focus method by using the image from the CCD overlapped sections was proposed.Firstly,the structure of CCD in the APRC was introduced.Based on the pushing-broom imaging characteristics,a Field Programming Gate Array(FPGA) which can process data in parallel model was used to receive the image data from multi-CCD overlapped sections and calculate the evaluation values of image quality at the same time.Then,three kinds of the CCD overlapped sections with the biggest evaluation values of image quality were selected as the gist for determining the focus direction.Finally,the feasibility of the method proposed was validated by an experiment.In the experiment,when the push-broom frequency is 10 kHz,the time for one focus step is 0.2 s,which illuminates that the proposed focusing method has good real-time ability,and it can offer a feasible gist for the on-track focus in the APRC.

This paper introduces a new type of automated container terminal system, which utilizes multistory frame bridges and rail-mounted trolleys to transport containers between the quay and the yard. For this new design concept, this paper makes an explorative study to identify the challenges and opportunity for it to be applied in transshipment hubs. We compare the transport efficiency and stacking capacity between this new system and the widely used AGV-based system. Several analytical models and performance measures are proposed for the quantitative comparisons between these two ACT systems.

According to the evaluation indexes of road lighting,the light distribution of Light Emitting Diode(LED) luminaries was optimized.A mathematical model of the illumination distribution for LED luminaries was established based on the relationship between the evaluation of road lighting and the illumination distribution.By taking the evaluation indexes of road lighting as the optimization conditions and the ratio(Q) of average luminance to average illuminance of road surface as an optimization target,the light distribution was obtained by solving a constrained optimization problem.Finally,the optimized light distribution was induced into lighting simulation software to simulate the LED luminaries for an asphalt trunk road.The result shows that the light distribution is asymmetric in the lateral direction,and the maximum intensity direction leans to the traffic lane.The light distribution saves 30.3% in energy consumption compared to traditional symmetrical light distribution.Moreover,the Q value is 0.072 7,which is higher than that of the normal asphalt trunk road.The evaluation of the road lighting meets the standard of CJJ 45-2006,and demonstrates that the lighting parameters are optimized well.

This paper studies two tactical level decision problems arising in transshipment hubs: berth template planning that is concerned with allocating berths and quay cranes to arriving vessels, and yard template planning that is concerned with assigning yard storage locations to vessels. These two tactical level decisions interact with each other. A mixed-integer programming model is proposed to integrate the berth template and the yard template planning with the aim to minimize the service cost that is incurred by the deviation from vessels' expected turnaround time intervals, and the operation cost that is related to the route length of transshipment container flows in yard. Moreover, a heuristic algorithm is developed for solving the problem in large-scale realistic environments. Numerical experiments are conducted to prove the necessity of the proposed model and also validate the efficiency of the proposed heuristic algorithm. For a set of real-world like instances, the heuristic algorithm can obtain good berth and yard templates within a reasonable time.

In many manufacturing industries, e.g. powder metallurgy, pharmaceuticals, ceramics and foodstuff, die compaction is widely applied. Although die filling has attracted increasing attention recently, very few published studies are available to predict powder flow rate from a moving feed shoe to dies. In this research, a feed shoe with three wheels of a high-speed rotary tablet press was studied. The powder discharge rates from the feed shoe and the tablet weight variability at different feeding wheel paddle speeds were investigated experimentally and numerically. The results of the two methods were in good agreement. According to the experimental results, the minimum deviation of tablet weight was obtained at the speed of 60 rpm. However, the wheel speed of 55 rpm was likely to be the better one on account of the calculations, which will be studied in the future experiments.

Product development is a knowledge-intensive activity in manufacturing enterprises. This paper analyses various forms of knowledge resources in the product development process and studies the representation scheme for them. Then a novel distributed knowledge sharing model is proposed for spreading and sharing knowledge among engineers in collaborative product development teams. In a collaborative team, engineers usually come from diverse disciplines; their demands for knowledge are also different from each other. The proposed knowledge sharing model could deliver the proper knowledge to the engineers who may need them. Moreover, our model is based on the engineers’ personal knowledge repositories rather than the centralised team knowledge repository in the collaborative team. The proposed model could bring out an efficient and proactive way for knowledge sharing among engineers in the product development process. The efficiency and usability of the proposed model are validated by experiments referring to ...

Collaborative team members usually come from diverse disciplines; their demands for information are also different from each other. This paper is mainly concerned with how to capture designers’ demands for information in a collaborative team. From a workflow perspective, designers’ information demand is modelled considering three aspects: members’, roles’, and tasks’ requirements for information. Based on a static model of information demand and information filtering technologies, a dynamic model is proposed so that the designers’ information demand could be derived automatically. In addition, the appropriate volume of information for designers’ needs could also be determined intelligently. With the information demand model, an information supply system could be developed to realize the following objective: the delivery of an appropriate volume of information within an appropriate domain, delivered to the appropriate user in the collaborative team.

Process route sequencing is considered as the key technology for computer aided process planning (CAPP) and is very complex and difficult. In this paper, based on the analyzing of various constraints in process route sequencing and the astringency of Genetic Algorithms (GAs), the GA is reconstructed, including the establishing of the coding strategy, the evaluation operator and the fitness function. The new GAs can meet the requirement of sequencing work and can meet the requirement of astringency. The natural number is adopted in coding strategy, the “elitist model” and the “tournament selection” are adopted as selection operators, the nonconforming sequential searching crossover operator is used and the inconsistent mutation operator is adopted, the fitness function is defined as a formula of the sum of compulsive constraints with each weighing, and these constraints are used as the control strategy for GAs in the searching process. By using GAs in the optimization, the optimal or near-optimal process route is obtained finally.

In order to meet the variable planning problem in mass customization, this paper presents a method of genetic algorithm to satisfy a set of customer requirements. Unlike former methods for platform planning that designers have to determine product platform variables and individual variables beforehand, this new method focuses on improving the commonality of the product family within the diverse customer needs, and then determines the individual variables and their variation range, as well as the common variables of product platform and their optimal values. A simulation experiment of electric motor designing is reported to illustrate the potential and the feasibility of this method.

This paper describes a preliminary attempt at using the knowledge grid technologies for knowledge supply platform in a distributed collaborative design environment. By integrating members, roles, and tasks in workflow, three sorts of knowledge demands are gained. Based on knowledge demand information, a knowledge supply model is proposed for the purpose of delivering the right knowledge to the right persons. Knowledge grid, acting as a platform for implementing the knowledge supply, is also discussed mainly from the view of knowledge space. A prototype system of knowledge supply has been implemented and applied in collaborative product development. The proposed platform is viewed as a promising knowledge management method that facilitates the implementation of computer supported cooperative work.

Although China has a large volume of iron ore deposits the grade of iron ore is very low. This has led to unfavourable conditions for developing China's iron and steel industry. In particular the big steel plants in East China have faced severe shortages of iron ore. China is a large developing country and the demand for finished steel is increasing rapidly. Consumption growth of finished steel cannot depend entirely on increased imports of steel. China will therefore develop its local iron and steel industry vigorously. In the coming ten years China's resource policy for iron ore is for the greater part to depend on domestic mining, but there will also be a step by step expansion of imports. As a result China's share of world trade in iron ore is expected to rise.

It is very helpful and illuminating to utilize a new method to reconstruct an ancient machine which does not exist now. This paper introduces a research experiment with the computer simulation on the astronomical clock tower built in ancient China. We have set a simulation model with computer software and tried to reconstruct the ancient machine and revealed its structure, working principle and target, etc. The technique will provide a new way that helps us to research the ancient machine and solve the mystery problems on it.

A new method was proposed to automatically determine parting line for molded part which includes undercut features and free form surfaces in the product model. The brief procedure included: 1) simplifying the product model by recognizing the undercut features and transforming the product solid model into the discrete surface model using the finite element method; 2) determining visibility of mesh based on an angle between normal vector of mesh and parting direction, and decomposing complex surface into single surfaces; 3) merging transitional surfaces into visible/invisible surface group based on merge rules and determining parting line by searching the largest edge loop of these two surface groups. Results from demonstration cases show that parting line can be easily determined using this method and efficiency of injection mold design is greatly improved.

Hydraulic Engine Mount (HEM) is now widely used as a highly effective vibration isolator in automotive powertrain. A lumped parameter model is a traditional model for modeling the dynamic characteristics of HEM, in which the system parameters are usually obtained by experiments. In this paper, Computational Fluid Dynamics (CFD) method and nonlinear Finite Element Analysis (FEA) are used to determine the system parameters. A Fluid Structure Interaction (FSI) FEA technique is used to estimate the parameters of volumetric compliances, equivalent piston area, inertia and resistance of the fluid in the inertia track and decoupler of a HEM. A nonlinear FEA method is applied to determine the dynamic stiffness of rubber spring of the HEM. The system parameters predicated by FEA are compared favorably with experimental data and/or analytical solutions. A numerical simulation for an HEM with an inertia track and a free decoupler is performed based on the lumped model and using the estimated system parameters, and again the simulation results are compared with experimental data. The calculated time histories of some variables in the model, such as the pressure in the upper chamber, the displacement of the free decoupler and the volume flow through the inertia track and the decoupler, under different excitations, elucidate the working mechanism of the HEM. The work conducted in the paper demonstrates that the method for estimating the system parameters in the lumped model for HEM is effective, with which the dynamic characteristic analysis and design optimization of an HEM can be performed before its prototype development, and this can ensure its high quality and low cost for development.

A Finite Element Analysis (FEA) of the static elastic characteristics of rubber isolators in automotive dynamic systems, such as suspension bushings and rubber springs of hydraulic engine mount, is carried out. The basic theory for the finite element analysis of rubber components is reviewed, and the method for conducting experiments for hyperelastic material constitutive model is studied. The specific requirement of the element for rubber FEA is also stated. As a case for studies, the stiffnesses of a complex rubber bushing subjected to radial, axial, torsional or tilting loading are calculated by Finite Element Method (FEM) and some closed form formulae based on regular bushing configuration. The results are compared with the experimental data. It is found that the FEM simulation results agree well with the experimental data. However, only one analytical formulation about the radial stiffness can give results close to the test data, and the predictions given by the other closed form solutions are far away from experimental results. As another case for studies, FEA on a rubber spring of a hydraulic engine mount is carried out to calculate the stiffnesses in three perpendicular directions. The results are also in good agreement with experimental data. This research demonstrate that the FEA method is effective for the static characteristic prediction of rubber components, and that FEA can play an important role in the design of rubber isolators.

A new kind of variable frequency speed-governing experiment system which has the structure of two parallel inverters at the DC bus and the output of the inverter driving two series asynchronous motors at the same shaft is presented in this paper. The results of the experiment show this creative AC variable frequency speed-governing experiment system can realize the load relationship of direct electromagnetic torque between the motor group, get the continuous control process easily for the reaction load and potential energy load during four quadrant operation, achieve total availability of the regenerative energy at any kind of load.

A design approach is presented in this paper for underactuation in robotic finger mechanisms. The characters of underactuated finger mechanisms are introduced as based on linkage and spring systems,The feature of self-adaptive enveloping grasp by underactuated finger mechanisms is discussed with feasible in grasping unknown objects. The design problem of robotic fingers is analyzed by looking at many aspects for an optimal functionality. Design problems and requirements for underactuated mechanisms are formulated as related to human-like robotic fingers. In particular,characteristics of finger mechanisms are analyzed and optimality criteria are summarized with the aim to formulate a general design algorithm. A general multi-objective optimization design approach is applied as based on a suitable optimization problem by using suitable expressions of optimality criteria. An example is illustrated as an improvement of finger mechanism in Laboratory of Robotics and Mechatronics (LARM) Hand. Results of design outputs and grasp simulations are reported with the aim to show the practical feasibility of the proposed concepts and computations.