Fabrication of gold nanoparticle pattern using imprinted hydrogen silsesquioxane pattern for surface-enhanced Raman scattering

This is the first report of surface-enhanced Raman scattering (SERS) substrate fabrication using a combination of imprinted hydrogen silsesquioxane (HSQ: HSiO_3/2) patterns and self-assembly of gold nanoparticles (AuNPs). To assemble the AuNPs inside the imprinted HSQ pattern, it is important to understand the interactions between AuNPs and AuNPs, and those between AuNPs and HSQ. The authors investigated the effects HSQ surface charges on the self-assembly of AuNPs. It was found that the negatively charged AuNPs were successfully assembled according to the geometry of the negatively charged HSQ pattern. In addition, it was shown that the SERS substrate fabricated from an HSQ consisting of an inorganic polymer was suitable for organic chemical analysis, by comparing it with a substrate fabricated using an organic polymer.     

SAM meets MEMS: reliable fabrication of stable Au-patterns embedded in PDMS using dry peel-off process

This paper describes a reliable method for fabrication of stable gold patterns embedded in polydimethylsiloxane (PDMS) using a direct peel-off process. Two different surface modifications with self-assembled monolayers were carried out for easy and reliable transfer of Au micro-patterns to the PDMS: (1) perfluorodecyltrichlorosilane on a Si substrate for easy release of the Au patterns from the Si substrate, and (2) (3-mercaptopropyl)trimethoxysilane on the Au patterns to promote the adhesion between the Au patterns and PDMS. Au features as small as 2 μm, in shapes of line and dots, were successfully transferred from the Si substrate to the PDMS over a 3-inch wafer. Transfer of Au patterns to PDMS using the dry peel-off process did not cause any contamination of PDMS, typically seen in wet chemical methods. Finally, the stability of the Au patterns embedded in PDMS was confirmed by the Scotch-tape adhesion test.     

The Aurora or-parallel Prolog system

Aurora is a prototype or-parallel implementation of the full Prolog language for shared-memory multiprocessors, developed as part of an informal research collaboration known as the “Gigalips Project”. It currently runs on Sequent and Encore machines. It has been constructed by adapting Sicstus Prolog, a fast, portable, sequential Prolog system. The techniques for constructing a portable multiprocessor version follow those pioneered in a predecessor system, ANL-WAM. The SRI model was adopted as the means to extend the Sicstus Prolog engine for or-parallel operation. We describe the design and main implementation features of the current Aurora system, and present some experimental results. For a range of benchmarks, Aurora on a 20-processor Sequent Symmetry is 4 to 7 times faster than Quintus Prolog on a Sun 3/75. Good performance is also reported on some large-scale Prolog applications.     

Syringe-assisted point-of-care micropumping utilizing the gas permeability of polydimethylsiloxane

By utilizing the high gas permeability of polydimethylsiloxane (PDMS), a simple syringe-assisted pumping method was introduced. A dead-end microfluidic channel was partially surrounded by an embedded microchamber, with a thin PDMS wall isolating the dead-end channel and the embedded microchamber. A syringe was connected with the microchamber port by a short tube, and the syringe plunger was manually pulled out to generate low pressure inside the microchamber. When sample liquid was loaded in the inlet port, air trapped in the dead-end channel would diffuse into the surrounding microchamber through the PDMS wall, creating an instantaneous pumping of the liquid inside the dead-end channel. By only pulling the syringe manually, a constant low flow with a rate ranging from 0.089 to 4 nl/s was realized as functions of two key parameters: the PDMS wall thickness and the overlap area between the dead-end channel and the surrounded microchamber. This method enabled point-of-care pumping without pre-evacuating the PDMS devices in a bulky vacuum chamber.     

High performance Prolog on a RISC

This paper presents some benchmark timings from an optimising Prolog compiler using global analysis for a RISC workstation, the MIPS R2030. These results are extremely promising. For example, the infamous naive reverse benchmark runs at 2 mega LIPS. We compare these timings with those for other Prolog implementations running on the same workstation and with published timings for the KCM, a recent piece of special purpose Prolog hardware. The comparison suggests that global analysis is a fruitful source of information for an optimising Prolog compiler and that the performance of special purpose Prolog hardware can be at least matched by the code from a compiler using such information. We include some analysis of the sources of the improvement global analysis yields. An overview of the compiler is given and some implementation issues are discussed. This paper is an extended version of Ref. 15)     

Rapid and low cost replication of complex microfluidic structures with PDMS double casting technology

In this paper, a new method for fast and precise replication of high-aspect-ratio microfluidic structures is reported. First, SU-8 microfluidic structures on the master mold were replicated into Polydimethylsiloxane (PDMS), which served as an intermediate, negative mold, by a conventional soft lithography process. The PDMS negative mold was then treated by wetting its surface with a diluted aqueous solution of a hydrophilic polymer, hydroxypropylmethylcellulose and rinsed with deionized water. Last, the negative mold was used in yet another PDMS molding process to produce a PDMS replica of the microfluidic structures (the hydrofocusing unit for a micro-cytometer) with the same structures as the master mold. Experimental results showed that microstructures with high-aspect-ratio could be consistently replicated with high fidelity. This technique can not only greatly simplify the design and fabrication of master molds, but also protect the expensive and fragile original master mold. The process does not require sophisticated equipment and is well suited for the replication of precision master structures in bulk quantities at low cost.     

The Prolog not-predicate and negation as failure rule

Clark’s query evaluation procedure for computing negative information in deductive databases using a “negation as failure” inference rule requires a safe computation rule which may only select negative literals if they are ground. This is a very restrictive condition, which weakens the usefulness of negation as failure in a query evaluation procedure. This paper studies the definition and properties of the “not” predicate defined in most Prolog systems which do not enforce the above mentioned condition of a safe computation rule. We show that the negation in clauses and the “not” Predicate of Prolog are not the same. In fact a Prolog program may not be in clause form. An extended query evaluation procedure with an extended safe computation rule is proposed to evaluate queries which involve the “not” predicate. The soundness and completeness of this extended query evaluation procedure with respect to a class of logic programs are proved. The implementation of such an extended query evaluation procedure in a Prolog system can be implemented by a preprocessor for executing range restricted programs and requires no modification to the interpreter/compiler of an existing Prolog system. We compare this proposed extended query evaluation procedure with the extended program proposed by Lloyd and Topor, and the negation constructs in NU-Prolog. The use of the “not” predicate for integrity constraint checking in deductive databases is also presented.     

Replication of sub-100 nm structures using h- and s-PDMS composite stamps

Soft-UV-NIL as replication technique was used to replicate sub-100 nm structures. The aim of this work is the stamp production and the replication of structures with dimensions smaller than 100 nm in a simple manner. Composite stamps composed of two layers, a thin hard PDMS layer supported by a thick soft PDMS (s-PDMS) layer are compared to common s-PDMS stamps regarding the resolution by using a Siemens star (star burst pattern) as test structure. The master is fabricated by electron beam lithography in a 140 nm thick PMMA resist layer. The stamp is molded directly from the structured resist, without any additional anti sticking treatment. Therefore the resist thickness determines the aspect ratio, which is 1.5 at the resolution limit. The replication is done in a UV-curing cycloaliphatic epoxy material. The employed test structure provides good comparability, the resolution limit at a glance, and it integrates a smooth transition from micro- to nanostructures. Therefore it is a capable structure to characterize the UV-NIL.     

A logic programming language based on the Andorra model

The Andorra model is a parallel execution model of logic programs which exploits the dependent and-parallelism and or-parallelism inherent in logic programming. We present a flat subset of a language based on the Andorra model, henceforth called Andorra Prolog, that is intended to subsume both Prolog and the committed choice languages. Flat Andorra, in addition todon’t know anddon’t care nondeterminism, supports control of or-parallel split, synchronisation on variables, and selection of clauses. We show the operational semantics of the language, and its applicability in the domain of committed choice languages. As an examples of the expressiveness of the language, we describe a method for communication between objects by time-stamped messages, which is suitable for expressing distributed discrete event simulation applications. This method depends critically on the ability to expressdon’t know nondeterminism and thus cannot easily be expressed in a committed choice language.     

Parallelizing Complex Streaming Applications on Distributed Scratchpad Memory Multicore Architecture

Multicore processors can provide sufficient computing power and flexibility for complex streaming applications, such as high-definition video processing. For less hardware complexity and power consumption, the distributed scratchpad memory architecture is considered, instead of the cache memory architecture. However, the distributed design poses new challenges to programming. It is difficult to exploit all available capabilities and achieve maximal throughput, due to the combined complexity of inter-processor communication, synchronization, and workload balancing. In this study, we developed an efficient design flow for parallelizing multimedia applications on a distributed scratchpad memory multicore architecture. An application is first partitioned into streaming components and then mapped onto multicore processors. Various hardware-dependent factors and application-specific characteristics are involved in generating efficient task partitions and allocating resources appropriately. To test and verify the proposed design flow, three popular multimedia applications were implemented: a full-HD motion JPEG decoder, an object detector, and a full-HD H.264/AVC decoder. For demonstration purposes, SONY PlayStation \(^{\circledR }\) 3 was selected as the target platform. Simulation results show that, on PS3, the full-HD motion JPEG decoder with the proposed design flow can decode about 108.9 frames per second (fps) in the 1080p format. The object detection application can perform real-time object detection at 2.84 fps at \(1280 \times 960\) resolution, 11.75 fps at \(640 \times 480\) resolution, and 62.52 fps at \(320 \times 240\) resolution. The full-HD H.264/AVC decoder applications can achieve nearly 50 fps.     

“LIGA2.X” process for mass production of single polymeric LIGA micro parts

The new modification of the LIGA process “LIGA2.X” is a promising process chain to replicate high accuracy single polymeric LIGA micro parts in large scale to feasible costs. The advantages of this new approach compared to the standard LIGA process are the reduction of fabrication costs, the elimination of any rework after replication, industry suitable mold technology for injection molding using a new developed demolding concept, optimized injection molding parameters for every single cavity, shot volumes of the parts below 0.5 mm³ and a new freedom in the arrangement of structure cavities in multicavity molds. Aspects covered in this paper are the introduction of the complete process chain of the new “LIGA2.X” process and the used mold concept for the micro-män 50 micro injection molding machine. Furthermore replicated single polymeric LIGA microparts fabricated using the new process chain are shown. To conclude, potential process improvements and future work will be outlined.     

A methodological approach to optimizing RFID deployment

The interest of adopting RFID continues to grow in many industries, ranging from supply chain automation to healthcare management. However, dynamics of the operating environment is one of the major challenges that impede RFID deployment. Even though numerous researchers focus on controlled laboratory experiments to enhance the success of deployment, it is found that system performance in the actual production environment may differ significantly from that conducted in a controlled laboratory, resulting in poor deployment result. To cope with this situation, this paper proposes an RFID Deployment Optimizer (RFIDDO), which is a generic methodology for optimizing the RFID configuration to provide objective, quantifiable data about the data capture performance of RFID readers for comparing and optimizing RFID applications in a scientific manner. A case study has also been conducted in a logistics company to demonstrate the implementation of RFIDDO and provide contextual details to help other firms in coping with the environmental dynamics in the journey of RFID deployment.     

Exploring aspects of cell intelligence with artificial reaction networks

The Artificial Reaction Network (ARN) is a Cell Signalling Network inspired connectionist representation belonging to the branch of A-Life known as Artificial Chemistry. Its purpose is to represent chemical circuitry and to explore computational properties responsible for generating emergent high-level behaviour associated with cells. In this paper, the computational mechanisms involved in pattern recognition and spatio-temporal pattern generation are examined in robotic control tasks. The results show that the ARN has application in limbed robotic control and computational functionality in common with Artificial Neural Networks. Like spiking neural models, the ARN can combine pattern recognition and complex temporal control functionality in a single network, however it offers increased flexibility. Furthermore, the results illustrate parallels between emergent neural and cell intelligence.     

A heuristic method for solving integer-valued decompositional multiindex problems

We consider NP-hard integer-valued multiindex problems of transportation type. We distinguish a subclass of polynomially solvable multiindex problems, namely multiindex problems with decomposition structure. We construct a general scheme for a heuristic method to solve a number of similar NP-hard decompositional multiindex problems. For one version of implementation for this scheme, we estimate its deviation from the optimum. We illustrate our results with the example of designing a class schedule.     

An efficient mutual authentication RFID scheme based on elliptic curve cryptography

Radio frequency identification (RFID) tags have been widely deployed in many applications, such as supply chain management, inventory control, and traffic card payment. However, these applications can suffer from security issues or privacy violations when the underlying data-protection techniques are not properly designed. Hence, many secure RFID authentication protocols have been proposed. According to the resource usage of the tags, secure RFID protocols are classified into four types: full-fledged, simple, lightweight, and ultra-lightweight. In general, non-full-fledged protocols are vulnerable to desynchronization, impersonation, and tracking attacks, and they also lack scalability. If the tag resources allow more flexibility, full-fledged protocols seem to be an attractive solution. In this study, we examine full-fledged RFID authentication protocols and discuss their security issues. We then design a novel RFID authentication protocol based on elliptic curve cryptography, to avoid these issues. In addition, we present a detailed security analysis and a comparison with related studies; the results show that our scheme is more resistant to a variety of attacks and that it has the best scalability, while maintaining competitive levels of efficiency.     

A Distributed Address Configuration Scheme for a MANET

This paper proposes a distributed address configuration scheme for a Mobile Ad hoc Network (MANET). The architecture for a MANET, the algorithm of constructing a MANET, and the algorithm for calculating a unique address space for the assignment are proposed. In the architecture, a common node has a unique address space for the assignment, and an isolated node can acquire a unique address from a neighboring common node without performing duplicate address detection. In this way, the address configuration task is distributed around common nodes. In this scheme, the control packets used for address configuration are exchanged within a one-hop scope, so the scalability is enhanced. This paper also presents an address recovery algorithm that can effectively retrieve the address resources released by failed nodes and the MANET merging/partitioning algorithm that can ensure a node’s address uniqueness. This paper compares the performance parameters of the proposed scheme and the existing schemes, including strong duplicate address detection and prime dynamic host configuration protocol, and the comparative results show that the address configuration cost of the proposed scheme is lower and the delay is shorter.