Optical encryption system that uses phase conjugation in a photorefractive crystal

We implement an optical encryption system based on double-random phase encoding of the data at the input and the Fourier planes. In our method we decrypt the image by generating a conjugate of the encrypted image through phase conjugation in a photorefractive crystal. The use of phase conjugation results in near-diffraction-limited imaging. Also, the key that is used during encryption can also be used for decrypting the data, thereby alleviating the need for using a conjugate of the key. The effect of a finite space-bandwidth product of the random phase mask on the encryption system's performance is discussed. A theoretical analysis is given of the sensitivity of the system to misalignment errors of a Fourier plane random phase mask.     

Photonic content-addressable memory system that uses a parallel-readout optical disk

We describe a high-performance associative-memory system that can be implemented by means of an optical disk modified for parallel readout and a custom-designed silicon integrated circuit with parallel optical input. The system can achieve associative recall on 128 × 128 bit images and also on variable-size subimages. The system's behavior and performance are evaluated on the basis of experimental results on a motionless-head parallel-readout optical-disk system, logic simulations of the very-large-scale integrated chip, and a software emulation of the overall system.     

A comparison of inventory cost reduction strategies in a JIT manufacturing system

Although many companies have found JIT manufacturing to be a very effective manufacturing strategy, few models have been developed which can help direct JIT efforts. This article discusses some of the problems with modelling JIT manufacturing, it describes some simple models of inventory costs in a JIT system and it uses these models to evaluate alternative inventory-cost reduction strategies in a printed circuit board (PCB) assembly system.     

Policy and cost approximations of two-echelon distribution systems with a procurement cost at the higher echelon

This paper investigates a two-echelon (warehouse-retailer) inventory system with stochastic demand and a pull system of inventory allocation. We assume that ordering costs are charged at the warehouse for procuring the item from a supplier. However, the internal costs of ordering the item from the warehouse by the retailers are considered negligible. For this problem, the lower echelon uses a single critical number, an order-up-to-level policy, whereas a (s, S) inventory system is followed at the upper echelon. We develop a cost model for this problem and provide a simple algorithm for estimating the optimal policy. Simulation is used to test the accuracy of the model.     

Dual-mesh optical tomography reconstruction method with a depth correction that uses a priori ultrasound information

A dual-mesh reconstruction method with a depth correction for near-infrared diffused wave imaging with ultrasound localization is demonstrated by use of phantoms and clinical cancer cases. Column normalization is applied to the weight matrix obtained from the Born approximation to correct the depth-dependent problem in the reconstructed absorption maps as well as in the total hemoglobin concentration maps. With the depth correction, more uniform absorption maps for target layers at different depths are obtained from the phantoms, and the correlation between the reconstructed hemoglobin concentration maps of deeply located, large cancers and the histological microvessel density counts are dramatically improved.     

Design and implementation of a virtual information system for agile manufacturing

In the new and emerging agile manufacturing paradigm, where multiple firms cooperate under flexible virtual enterprise structures, there exists a great need for a mechanism to manage and control information flow among collaborating partners. In response to this pressing need, this paper addresses the design and implementation of an agile manufacturing information system integrating manufacturing databases dispersed at various partner sites. We propose a framework in which: (1) information is modeled in a hierarchical fashion using object-oriented methodology (OOM); (2) information transactions are specified by the workflow hierarchy consisting of partner workflows; (3) information flow between partners is controlled by a set of distributed workflow managers (WM) interacting with partner knowledge bases, which reflect partner specific information control rules on internal data exchange, as well as inter-partner mutual protocols for joint partner communications; (4) the prototype system is accomplished using the World Wide Web based on a client-server architecture. The overall approach and system provides within a dynamic environment, where virtual partnerships are synthesized in response to specific business initiatives, a dynamic and flexible mechanism to support partner information exchange and to keep the dispersed information consistent.     

The integration of manufacturing and cost information into the engineering design process

In manufacturing systems engaged in the batch manufacture of discrete products, critical decisions on materials and processes are made during the design phase, decisions having significant impact on costs of production. A new computer aided design tool has been developed to enable product designers in small to medium size companies to incorporate manufacturability and cost criteria into their decision making. The paper describes the rationale of the system and its mode of operation. Experiments to validate its practicality and usefulness have yielded encouraging results.     

Pricing and lot-sizing decisions in a two-echelon system with transportation costs

We consider a single-buyer single-supplier system. The market demand is sensitive to the selling price set by the buyer. Both the buyer and the supplier operate with unit product costs, inventory holding costs, and order placement costs. In addition, the buyer is responsible for the freight cost. We formulate a model for determining the optimal lot-sizing and pricing decisions. Existing models for the problem do not consider the transportation costs with price sensitive market demand, and determine the optimal decisions through an exhaustive search. We propose an approximate solution procedure, and report the computational results on the effectiveness of the proposed procedure.     

Implementation of a high-speed face recognition system that uses an optical parallel correlator

We implement a fully automatic fast face recognition system by using a 1000 frame/s optical parallel correlator designed and assembled by us. The operational speed for the 1:N (i.e., matching one image against N, where N refers to the number of images in the database) identification experiment (4000 face images) amounts to less than 1.5 s, including the preprocessing and postprocessing times. The binary real-only matched filter is devised for the sake of face recognition, and the system is optimized by the false-rejection rate (FRR) and the false-acceptance rate (FAR), according to 300 samples selected by the biometrics guideline. From trial 1:N identification experiments with the optical parallel correlator, we acquired low error rates of 2.6% FRR and 1.3% FAR. Facial images of people wearing thin glasses or heavy makeup that rendered identification difficult were identified with this system.     

The implication of capacity reservation contracts in assembly system with asymmetric demand information

This paper investigates an assembly system that consists of one assembler and two suppliers who produce complementary components. The assembler possesses some private demand information that is unobservable to the upstream suppliers, and the two suppliers have to choose their capacity reservations ahead of the selling season. To induce credible vertical information sharing, we design three capacity reservation contracts: the price-quantity contract, the price-only contract and the hybrid price-quantity and price-only contract, so as to identify how the firms’ equilibrium reservation strategies and pay-offs react under different contract schemes. The results show that the assembler obtains the highest pay-off under either the price-only contract or the hybrid contract, which is determined by whether the private demand information or the demand fluctuation is sufficiently high. The suppliers’ optimal contract types are further influenced by their decision sequence. In particular, the supplier who makes decision earlier prefers the hybrid contract, while the supplier who makes decision later prefers any of the three contracts. The supply chain generates the highest pay-off from either the price-quantity contract or the hybrid contract.     

Two-wavelength interferometry that uses a fourier-transform method

Two-wavelength interferometry that is based on a Fourier-transform method has been investigated. A phase profile at a synthetic wavelength has been measured from a two-wavelength interferogram with two spatial carrier frequencies. A phase error caused by the difference between modulation intensities at two wavelengths has been theoretically and numerically analyzed. A phase map without the error can be obtained from a power-spectrum adjustment in the two-wavelength interferogram.     

Novelty filter that uses a bacteriorhodopsin film

We propose a new novelty optical filter that uses a bacteriorhodopsin film. This filter is based on the time-dependent nonlinear diffraction efficiency of real-time holograms recorded in the film. As soon as the signal beam carrying a pattern is diffracted by the polarization hologram recorded in the bacteriorhodopsin film, it begins to erase the hologram and suppresses the diffraction of the beam at the position of the stationary part of the pattern. This filter enhances only leading edges of moving patterns. In this system undesired scattered light, which is orthogonally polarized to the diffracted beam, is discriminated by a polarizer.     

Object-oriented modelling of manufacturing information system for collaborative design

Object-oriented technology has been widely acclaimed as offering a revolution in computing that is resolving a myriad of problems inherent in developing and managing organisational information processing capabilities. Although its foundations arose in computer programming languages, object-oriented technology has implications for a wide range of business computing activities including: programming, analysis and design, information management, and information sharing. The problematic issues in the development of manufacturing software systems are related to the various characteristics of manufacturing systems, which are wide, dynamic and complex. Design for manufacturing (DFM) is the integrated practice of designing components while considering their manufacturability, and its benefits are widely acknowledged in the industry. A model has been developed using object oriented technology, after analysing the fundamental elements necessary for modelling manufacturing and process planning framework used in collaborative design and manufacturing in machine tool manufacturing. The main components of this model are: process planning model (PPM), manufacturing activity model (MAM), manufacturing resource model (MRM) and manufacturing cost and time model. We are using ontologies in conjunction with specific conceptual models, which can contribute to improve the interoperability between these models. The performance of this model is shown by means of one real world case. The developed manufacturing information based design tool integrated with an intelligence design system can be used for collaborative design and manufacturing, which will support machine tool designers’ to achieve cost effective and timely design.     

An event-driven manufacturing information system architecture for Industry 4.0

Future manufacturing systems need to be more flexible, to embrace tougher and constantly changing market demands. They need to make better use of plant data, ideally utilising all data from the entire plant. Low-level data should be refined to real-time information for decision-making, to facilitate competitiveness through informed and timely decisions. The Line Information System Architecture (LISA), is presented in this paper. It is an event-driven architecture featuring loose coupling, a prototype-oriented information model and formalised transformation services. LISA is designed to enable flexible factory integration and data utilisation. The focus of LISA is on integration of devices and services on all levels, simplifying hardware changes and integration of new smart services as well as supporting continuous improvements on information visualisation and control. The architecture has been evaluated on both real industrial data and industrial demonstrators and it is also being installed at a large automotive company. This article is an extended and revised version of the paper presented at the 2015 IFAC Symposium on Information Control in Manufacturing (INCOM 2015). The paper has been restructured in regards to the order and title of the chapters, and additional information about the integration between devices and services aspects have been added. The introduction and the general structure of the paper now better highlight the contributions of the paper and the uniqueness of the framework.     

Product quality choice in two-echelon supply chains under post-sale liability: insights from wholesale price contracts

This paper considers a two-echelon supply chain consisting of an upstream manufacturer (M) and a downstream Retailer (R) who transact intermediate products via a wholesale price contract. The supply chain provides an experience good to unit-demand consumers. M is liable for the harm caused by its products in a low quality state. A two-stage game model is built to describe how the supply chain operates. With the equilibrium and under certain assumptions, this paper finds that (1) in spite that post-sale product liability positively affects the wholesale price, M’s quality level, the contracted quantity and supply chain members’ profitability are independent of it; (2) when liability-related factors and M’s quality improvement efficiency change, the wholesale price serves as a medium for M and R to mutually share the ex ante expected liability cost, the demand loss caused by the ex ante expected consumer harm and the ex ante quality-improving cost; (3) in response to changes in liability-related factors, the quality performance is in conflict with the financial performance for both M and R, but this conflict disappears in the presence of a change in quality improvement efficiency. Managerial insights are also discussed.     

Photorefractive beam-steering system that uses energy transfer in a BaTiO(3) crystal for a fiber-array interconnect

A beam-control system to write gratings on a holographic plane is studied. The arrangement is designed to interconnect two 1024 monomode fiber arrays. The beam-control system is composed of two subsystems: a beam steerer, which deflects one incident beam toward 1024 positions, and a collimating system, which adapts the shape of the deflected beam to the holographic plane. The collimating system was studied only after the beam steerer had been fully built and tested. It is based on the photorefractive amplification of a beamlet selected by a shutter array. The deflection efficiency is enhanced by a factor 1500 with the photorefractive crystal, and the signal-to-noise ratio is larger than 5500. The influence of the optical aberrations on the coupling losses of the infrared beams in the monomode fibers are evaluated.     

An easily implementable hierarchical heuristicfor a two-echelon spare parts distribution system

This paper addresses a two-echelon spare parts stocking and distribution system consisting of a central Distribution Center (DC) and regional facilities. Because the primary purpose for holding inventory is to provide timely repairs of customer′s equipment, we set as our objective to minimize total inventory investment subject to constraints on the delay due to parts outages. We decompose the resulting problem by level and by facility. By simplifying the expressions for the delay constraints and applying previously developed heuristics for the single-level problem [1], we are able to derive closed-form expressions for the inventory control parameters. We then develop a search algorithm (on DC fill rate) to approximate the parameters (Lagrange multipliers) in the closed-form expressions. Numerical comparisons against an analytic lower bound and, for small problems, exact solutions show the approximation to be quite accurate. We also found that it outperforms methods currently in use by the firm that motivated this work. Finally, because it yields closed-form expressions for inventory control parameters and the parameters are only updated periodically, the policy is “easily implementable” once suitable Lagrange multipliers have been computed.     

The trans-shipment problem in a two-echelon,multi-location inventory system with lost sales

In this paper, we address a two-echelon, multi-location pooling inventory system that consists of an outside supplier, a warehouse and two retailers. To control their inventories, both warehouse and retailers use (R,?s,?S) policy. The retailers face stochastic customer demands for a single product and the warehouse receives only the replenishment orders of retailers. In case of stock-out at retailers, emergency trans-shipments are used to satisfy the unmet demand at one retailer with the surplus from the other retailer. When the stock is insufficient at the warehouse, we propose two rationing policies to allocate on-hand stock between retailers. The demand that cannot be satisfied neither by stock on-hand nor by trans-shipment from retailers is considered lost. Our work has two objectives. First, we propose an inventory model based on three components: the optimisation inventory model, the trans-shipment policy and the rationing policies for determining the best values of (s,?S) at each location that minimise total system cost. Second, we validate this model via an empirical simulation study that allows us to identify the influential parameters on trans-shipment benefits.     

Prism fingerprint sensor that uses a holographic optical element

A prism fingerprint sensor is described that uses a holographic grating glued to a right-angled prism. A light source normally illuminates the hypotenuse side of the prism with the finger pressed against the grating. The ridges and valleys of the finger are sensed on the basis of the principle of total internal reflection. The grating is used essentially to correct the distortion usually present with prism sensors. The quality of the fingerprint is very good: the pores on the ridges can be seen.     

Loading a flexible manufacturing system

This paper examines the problem of master scheduling for an FMS in Scotland containing six CNC horizontal boring machines. A multiple criteria approach is used to choose the compatible subset of candidate orders for processing by this FMS, subject to resource constraints and potentially conflicting performance objectives. A structured framework for conflict resolution is described and compromise solutions are obtained using standard mathematical programming software.