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Capacitive pressure sensors based on porous structures have been extensively explored for various applications because their sensing performance is superior to that of conventional polymer sensors. However, it is challenging to develop sufficiently sensitive pressure sensors with linearity over a wide pressure range owing to the trade-off between linearity and sensitivity. This study demonstrates a novel strategy for the fabrication of a pressure sensor consisting of stacked carbon nanotubes (CNTs) and polydimethylsiloxane. With the addition of carbon nanotubes, the structure is linearly compressed due to the reinforced mechanical properties, thereby resulting in high linearity. Additionally, the percolation effect is boosted by the CNTs having a high dielectric constant, thus improving the sensitivity. The pressure sensor exhibits linear sensitivity (R2 = 0.991) in the medium-pressure range (10-100 kPa). Furthermore, it delivers excellent performance with a fast response time (∼60 ms), in conjunction with high repeatability, reproducibility, and reliability (5 and 50 kPa/1000 cycles). The fabricated sensors are applied in wearable devices to monitor finger bending and detect finger motions in real time with high precision. The large-area sensor is integrated with a neural network to accurately recognize the sitting posture on a plane, thereby demonstrating the wide-range detection performance.

Describe multi-period input (MPI) model and multi-period output (MPO) model.Modify the MPO model to consider consistent time lag effect.Some lemmas are given to describe some properties of the suggested model.Compare MPO and consistent time lag MPO using the data set of long term R&D projects. Conventional data envelopment analysis (DEA) models assume that the inputs of a specific period are consumed to produce the outputs of the same period. However, in some applications, the inputs of a period can be thought to partially contribute to the outputs of several subsequent periods. This can be described as time lag effects for performance evaluation. A few researches have presented DEA models using the time lag weights of input or output factors to address the time lag effects. In those models, the weights for the time lag effects can vary by period. In this paper, we propose another DEA model with consistent weights for time lag effects throughout the periods. The proposed model is more realistic and more discriminative than the existing time lag model. We present the results of a case example for comparison of the proposed model and the existing time lag model.

Robust combinatorial optimization problems with cardinality constrained uncertainty may be solved by a finite number of nominal problems. In this paper, we show that the number of nominal problems to be solved can be reduced significantly.

We consider a robust shortest path problem when the cost coefficient is the product of two uncertain factors. We first show that the robust problem can be solved in polynomial time by a dual-variable enumeration with shortest path problems as subproblems. We also propose a path enumeration approach using a K -shortest paths finding algorithm that may be efficient in many real cases. An application in hazardous materials transportation is discussed, and the solution methods are illustrated by numerical examples. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013

In this study, an improved scheme for distance-based r egistration (DBR) is proposed and its performance isanalyzed. In the DBR, when a mobile station (MS) enters a new cell, it calculates the distance between last registeredcell and current cell and registers its location if the distance reaches reference distance D . In this study, two-locationDBR (TDBR) is proposed to improve the performance of the DBR. In the TDBR, an MS stores not only lastregistered location area (LA) but also previously registered LA, and then no registration is needed when the MScrosses two LAs stored already. However, since the TDBR may increase paging cost, trade-off is necessary betweendecreased registration cost and increased paging cost. In this study, the performances of two schemes are analyzedand compared using 2-dimensional random walk mobility model in hexagonal cell configuration. We show that ourmathematical analysis is accurate by comparing with simu lation. From the numerical results for various circum-stances, it is shown that our proposed TDBR outperforms current DBR in most cases.

We consider a network design problem which has shortest routing restriction based on the values determined by the installed facilities on each arc. In conventional multicommodity network design problem, a commodity can be routed through any possible path when the capacity is available. But, we consider a problem in which the commodity between two nodes must be routed on a path which has shortest metric value and the link metric value is determined by the installed facilities on the link. By this routing restriction, the problem has a distinct characteristic. We present an integer programming formulation containing the primal-dual optimality conditions to the shortest path routing. We give some computational results for the model., {"references":["R. K. Ahuja, Thomas L. Magnanti, and James B. Orlin. (1993) Network\nFlows: Theory, Algorithms, and Applications. Prentice-Hall, Inc., Upper\nSaddle River, NJ, USA.","M. Fischetti, Polo, C., and Scantamburlo, M. (2004). A local branching\nheuristic for mixed-integer programs with 2-level variables, with an\napplication to a telecommunication network design problem. Networks,\n44(2), 61-72.","B. Gendron, Crainic, T. G., and Frangioni, A. (1999). Multicommodity\ncapacitated network design. Springer US.","E. Gourdin, Labb, M., and Yaman, H. (2001). Telecommunication and\nlocation.","K. Holmberg and Yuan, D. (2000). A Lagrangian heuristic based\nbranch-and-bound approach for the capacitated network design problem.\nOperations Research, 48(3), 461-481.","D. S. Johnson, Lenstra, J. K., and Kan, A. H. G. (1978). The complexity\nof the network design problem. Networks, 8(4), 279-285.","B.Y. Kara and V. Verter, Designing a road network for hazardous materials\ntransportation, Transportation Science, 38(2):188, 2004.","K.T. Ko, Tang, K.S.,Chan, C.Y. and Man, K.F. (1997). Packet Switched\nCommunication Network Design using GA. Proceeings of GARESIA97,\n398 - 403","T. Lee, S. Park and K. Park, (2000) A Genetic Algorithm for Packet Data\nNetwork Design, Proceedings of INFORMS-KORMS Seoul 2000.\n[10] S. Pierre and Legault, G. (1996) An Evolutionary Approach for\nConfiguring Economical Packet Switched Computer Networks. Artificial\nIntelligence in Engineering, 10, 127-134"]}

Multicast routing and wavelength assignment (MC-RWA) is an important issue when designing multicast WDM ring networks. Two heuristic multicast routing methods, minimum spanning tree (MST) and shortest path routing (SPT), have been studied extensively. However, the comparison of those two heuristics in terms of the number of required wavelengths is still an open issue because of the lack of efficient optimization methods for MC-RWA. In this paper, using a recently developed optimization algorithm, we compare the two multicast routing methods and optimal MC-RWA. The results show that SPT requires about 1---12% more wavelengths than MST. Moreover, the number of required wavelengths under MST routing is shown to be very close to that of the optimal solution.

This study considers paging schemes that can page some cells or only one cell within the location area to reduce paging cost by using PAs (Paging Agents) and compares their performances by using a new analytic method. There are three ways of paging schemes using PAs; BSPA (Base Staton Paging Agent), 2SPA (2-Step Paging Agent), LAPA (Location Area Paging Agent). This study proposes exact performance of BSPA and 2SPA using a new analytic method based on Markov chain modeling to find the most efficient paging scheme. Numerical results for various circumstances are presented by using proposed analytic method to select a proper paging scheme in mobile communication networks.

This paper suggests a component-based software development framework for 3rd party logistics (3PL) business. This framework integrates two engineering methodologies in order to identify the most reusable software components that can be used in several types of 3PL business models. UML (Unified Modeling Language) is used to design lower-level software components and DEMO (Design and Engineering Methodology for Organization), one of the business engineering methodologies based on the communication theory, is used to identify core business processes for 3PL business models. By using the methodologies, we develop a 3PL management solution by applying the framework into a C2C type of 3PL business model, specifically the door-to-door (D2D) service.

This study examines movement-based registration (MBR). In MBR, a mobile station (MS) performs location registration whenever the number of entering cells reaches the specified movement threshold M. MBR is simple and its implementation is quite straightforward. However, it may result in more registrations than other similar schemes. We propose an improved MBR scheme, in which MBR combines with implicit registration (IR), to reduce registration cost. The performance of the proposed scheme is evaluated using a mathematical approach based on the 2-dimensional random walk mobility model in a hexagonal cell configuration. The numerical results for varying circumstances show that the proposed scheme performs better than conventional MBR.

We consider the routing and wavelength assignment (RWA) in survivable WDM network. A path protection scheme assumed and two different wavelength assignment meth- ods for protection paths are considered. Integer programming formulations of RWA under two wavelength assignment methods are proposed and we devised algorithms to solve them. Test results show that the difference of wavelength requirements between two wavelength assignment methods is 5-30%.

This paper considers a routing and wavelength assignment problem (RWAP) for the implementation of efficient Wavelength Division Multiplexing all-optical mesh networks without wavelength conversion. For a given physical network and required connections, the solution to the RWAP consists in how to select a suitable path and wavelength among the many possible choices for each connection so that no two paths using the same wavelength pass through the same link, while minimizing the number of required wavelengths. We introduce an integer programming formulation of the RWAP, which has an exponential number of variables, and propose an algorithm to solve it based on the column generation technique. The proposed algorithm can yield high quality solutions and tight lower bounds at the same time. Though the proposed algorithm cannot guarantee optimal solutions, computational results show that the algorithm yields provably good solutions within a reasonable time.

We consider the time slot assignment problem (TSAP) in a cluster of satellite-switched time-division multiple-access (SS/TDMA) satellite system with intersatellite links (ISL). The problem is known to be NP-complete. In this paper, we consider TSAP as a graph coloring problem on a bipartite multigraph which is constructed from the traffic requirements. We give an integer programming (IP) model for TSAP and propose an algorithm based on the column generation technique. Computational results using randomly generated data are reported.

We consider the multicast routing and wavelength assignment (MC-RWA) problem on WDM bidirectional ring networks without wavelength conversion. We give an integer programming formulation of the problem and propose an algorithm to solve it optimally. The algorithm is based on column generation and branch-and-price. We test the proposed algorithm on randomly generated data and the test results show that the algorithm gives optimal solutions to all of the test problems.

A DEA model can generally evaluate the performance using multiple inputs and outputs for the same period. However, it is hard to avoid the production lead time phenomenon some times, such as long-term project or marketing activity. A couple of models have been suggested to capture this time lag issue in the context of DEA. This paper develops a dual-MPO model to deal with time lag effect in evaluating efficiency. A numerical example is also given to show that the proposed model can be used to get efficiency and reference set of inefficient DMUs and to obtain projected target value of input attributes for inefficient DMUs to be efficient., {"references":["","Charnes A, Cooper WW, Rhodes E (1978) Measuring the efficiency of\ndecision-making units. Eur J Oper Res 2:429–444.","Banker, R.D., Chames, A., and Cooper, W.W. (1984) \"Some models for\nestimating technical and scale inefficiencies in Data Envelopment\nAnalysis\", Management Science 30/9, 1078-1092.","Charnes, A., and Cooper, W.W. (1985), \"Preface to topics in Data\nEnvelopment Analysis\", Annals of Operations Research 2, 59-94.","Chames, A., Cooper, W.W., Golany, B., Seiford, L., and Stutz, J.\n(1985),\"Foundations of Data Envelopment Analysis for\nPareto-Koopmans efficient empirical production functions\", Journal of\nEconometrics 30, 91-107.","Chames, A., Cooper, W.W., Wei, Q.L., and Huang, Z.M. (1990),\n\"Fundamental theorems of non-dominated solutions associated with\ncones in normed linear space\", Journal of Mathematical Analysis and\nApplications 150/1, 54-78.","Seiford, L.M., and Thrall, R.M. (1990), \"Recent developments in DEA,\nthe mathematical programming approach to Frontier Analysis\", Journal of\nEconometrics 46, 7-38.","Yu, G., Wei, Q.L., and Brockett, P. (1996), \"A Generalized Data\nEnvelopment Analysis model: A unification and extension of existing\nmethods for efficiency analysis of decision making units\", Annals of\nOperations Research 66.","Post T, Spronk J (1999) Performance benchmarking using interactive data\nenvelopment analysis. Eur J Oper Res 115:472–487.","Ozgur Ozpeynirci and Murat Kokslan(2007) Performance evaluation\nusing data envelopment analysis in the presence of time lags. J Prod Anal\n27:221–229.\n[10] Zhang Y.S. and Jeong, B.H.(2012), \"A DEA model for Performance\nEvaluation in The Presence of Time Lag Effect\", World Academy of\nScience, Engineering and Technology, 69, 611-61.\n[11] Cooper, W.W., Seiford, L. M., Tone, K.(2006), Introduction to Data\nEnvelopment Analysis and Its Uses, Springer Science, New York, USA."]}