Tsutomu Inamoto

A call-based integer programming model for static elevator operation problems

In this paper, we propose an integer linear programming (ILP) model for static elevator operation problems. The proposed model is based on hall- and car-calls which correspond to pickup and delivery requests in pickup-and-delivery problems (PDPs), thus is similar to ILP models for PDPs. The primary difference between those models and the proposed model is the prevention of the reverse run, which means that an elevator with a passenger is moved to the direction opposite to that of the passenger. In computer illustrations, the proposed model is roughly investigated by being compared with a trip-based ILP model which has been proposed by the authors.

Injecting speculation on ideal trajectories into a trip-based integer programming model for elevator operations

In this paper, we propose a technique for a trip-based integer programming model for elevator operations to decrease computational times in solving problems for multiple elevators. The technique is inspired by the speculation on ideal trajectories of elevators, where the interval of arriving floors is equal to each elevator. Such trajectories are regarded as oscillating waves. It is expected that limiting movements of elevators to resemble such waves may decrease computational times without degradation on the objective value. This expectation is numerically examined by obtaining optimal trajectories of some problem instances.

Giving formal roles to elevators for breaking symmetry in static elevator operation problems

In this paper, we propose a technique to decrease computational times in solving an integer linear programming (ILP) model for the static elevator operation problem (SEOP). The SEOP is a problem to optimally operate elevators on such assumption that all information on passengers who use an elevator system is known beforehand. In planning, there is a symmetry on elevators that exchanging 2 elevators does not affect the value of the objective function, if initial states of those elevators are identical. Such symmetry requires much computational times for problems to be solved, since there are at least 2 optimal solutions which differ only in allocations of elevators and partial solutions for those solutions can not be bound. That symmetry is resolved by giving different roles to elevators, and those roles are assignment pattern numbers (APNs) in the proposed technique. An APN of an elevator is a decimal number which is calculated from a binary vector which represents assignments of passengers to that elevator. The proposed technique deploys such a straightforward fact that all elevators have different APNs, and enfoces an elevator with a smaller index to have a smaller APN than other elevators with larger indexes. The effectiveness of that technique is numerically examined by applying a mathematical solver to ILP equations generated from some problem instances.

The analysis of Automated HTML5 Offline Services (AHOS)

The traditional Web-based applications operate only when connected to the network. Many realities in a field require a Web-based application that is applicable even in case of offline. We have proposed the Automated HTML5 Offline Service (AHOS), presented as the integration of advanced services, developing with HTML5 Application Programming Interfaces (APIs) to provide Web-based applications with the ability to work offline. When the AHOS Web-based application visits at the Web server for the first time, the Web server will notify the application the list of files required to be downloaded. Then after being downloaded, the Web application can work successfully and continuously even though the network connection from the client to the server is unavailable. Moreover, if the connection to the server is re-connected, any changes that have been made during offline will be automatically uploaded. The present study describes the requirements and implementation stages of AHOS concept for Web-based applications. Several current status and challenges of AHOS concept are also explained. The performance analyses of the AHOS concept are performed in a case of Web-based maintenance Decision Support System (DSS) for Small and Medium Industries (SMIs). The results of the study are very useful in providing in-depth understanding of the advantages and limitations, and as the future directions in applying this AHOS concept to other Web-based applications.

Road-Map to Bridge Theoretical and Practical Approaches for Elevator Operations

In this paper, we propose a road-map to bridge theoretical and practical approaches in the discipline of the elevator operation problem (EOP). The theoretical approach is to obtain optimal solutions for static EOPs, here “static” means all information on users of the elevator system is known before scheduling. The practical approach is to construct rule-bases for realistic situations. The proposed road-map is comprised of 5 stages: (1) to obtain a formally-optimal solution for a problem instance of a static EOP, (2) to construct a statically-peculiar optimal rule-base from the optimal solution, (3) to construct a dynamically-peculiar optimal rule-base which is effective for the problem instance and functions on a continuous elevator system, (4) to construct a dynamically-narrow rule-base which is effective for a set of problem instances, and (5) to construct a dynamically-wide rule-base which is effective for various sets of problem instances. In computer illustrations, preliminary verification on earlier stages are displayed.

Design and Implementation of Data Synchronization and Offline Capabilities in Native Mobile Apps

This paper describes a solution for data synchronization, mobile offline capabilities, and network bandwidth optimization by utilizing a native smart device app as a distributed storage system. The solution aggregates the best practices in business and academic research to achieve a reduction in redundant data transfer and an ability to work offline in smart devices.

Evaluation of Influence Exerted by a Malicious Group’s Various Aims in the External Grid

The external grid is one of grid computing systems. It is composed of numerous computers connected to the Internet. Although the external grid realizes high performance computing, it is necessary to guarantee the robustness against malicious behaviors of the computers. In the previous literature, a technique to protect program codes against such behaviors has been proposed; however, only one type of malicious behavior is considered to evaluate the effectiveness of the technique in the literature. In reality, malicious behaviors vary according to the purpose of malicious groups. The goal of the research in this paper is to guarantee the safety of the external grid in a quantitative way. In order to achieve the goal, we evaluate the effectiveness of concealing processes against several types of malicious behaviors.

Decreasing computational times for solving static elevator operation problems by assuming maximum waiting times

In this paper, we propose a technique to decrease computational times for solving static elevator operation problems which are formalized as trip-based integer linear programming models. The technique is comprised of two parts: (i) to give equations which constrain the search space on the assumption that the maximum waiting time over passengers of an optimal solution is known, and (ii) to estimate such time as longest round-trip times. Computational results indicate that the technique can basically decrease computational times without degrading objective function values when maximum waiting times are less than estimated values and the number of equipped elevators is 1.

Intermittently Proving Dynamic Programming to Solve Infinite MDPs on GPUs

In this paper, we propose a variant of the dynamic programming which is suitable for solving infinite Markov decision processes on GPUs. The primary feature of the proposed method is to not always but intermittently transfer and check values for proving the convergence of the procedure. It is expected for the proposed method to decrease computational times by suppressing surplus transfers and checks of values. This expectation is verified through applications of some dynamic programming programs to a simple animat problem and the mountain-car problem.