An efficient signature computation method

A signature generation algorithm for linear-feedback shift register (LFSR)-based compactors used in fault simulation of built-in self-test digital circuits is presented. The algorithm uses small- to medium-size lookup tables to generate signatures for internal as well as external exclusive-OR LFSRs of any length. The basic concept can be extended to general linear compactors. Algorithms that convert signatures from one form of LFSR to the other are also presented     

Fault diagnosis in loop-connected systems

The paper considers fault diagnosis in a large system comprising a collection of small subsystems or units which can test one another for the existence of a faulty condition. If subsystem α is not faulty and tests subsystem β, a correct indication of the status of β is obtained; if α is faulty, the test outcome contains meaningless information. A particular form of interconnection is examined. For a system with n units u_o,u₁,…,u_{n ? 1}, for each i unit u_i tests u_{i + 1},u_{i + 2},…,u_{i + A} (modulo n arithmetic being understood), where A is a preselected integer. If t is the maximum number of faulty units, we show that when t ? A, all faults are immediately diagnosable if n ? 2t + 1; we also show that when t ? A, at least A faults can be diagnosed if and only if n ? s(t ? As) + t + A + 1, where s is the integer which maximizes the quadratic function f(x) = x(t ? Ax) of the integer variable x.     

DNA hybridization on silicon nanowires

Nanowire-based detection strategies provide promising new routes to bioanalysis and indeed are attractive to conventional systems because of their small size, high surface-to-volume ratios, electronic, and optical properties. A sequence-specific detection of single-stranded oligonucleotides using silicon nanowires (SiNWs) is demonstrated. The surface of the SiNWs is functionalized with densely packed organic monolayer via hydrosilylation for covalent attachment. Subsequently, deoxyribonucleic acid (DNA) is immobilized to recognize the complementary target DNA. The biomolecular recognition properties of the nanowires are tested via hybridization with ^γP³² tagged complementary and non-complementary DNA oligonucleotides, showing good selectivity and reversibility. No significant non-specific binding to the incorrect sequences is observed. X-ray photoelectron spectroscopy, fluorescence imaging, and nanodrop techniques are used to characterize the modified SiNWs and covalent attachment with DNA. The results show that SiNWs are excellent substrates for the absorption, stabilization and detection of DNA sequences and could be used for DNA microarrays and micro fabricated SiNWs DNA sensors.     

Synthesis and evaluation of a fluorescent non-peptidic cholecystokinin-B/gastrin receptor specific antagonist for cancer cell imaging

Fluorescent labeling has enabled a better understanding of the relationships between receptor location, function, and life cycle. Each of these perspectives contributes new insights into drug action, particularly for G protein‐coupled receptors (GPCRs). The aim of this study was to develop a fluorescein derivative, FLUO‐QUIN—a novel antagonist of the cholecystokinin‐B/gastrin receptor. A radioligand‐binding experiment revealed an IC₅₀ of 4.79 nm, and the antagonist inhibited gastric acid secretion in an isolated lumen‐perfused mouse stomach assay (up to 51 % at 100 nm) . The fluorescence properties altered upon binding to the receptor, and the fluorophore was quenched to a greater extent when free than in the bound form. FLUO‐QUIN specifically bound to human pancreatic carcinoma cells, MiaPaca‐2, which are known to express the receptor, as evidenced by rapid clustering followed by time‐dependent receptor internalization. This proves the stability of FLUO‐QUIN and its ability to penetrate vesicular membranes and reach various cell targets. Hence it might be used as an agent for the detection of CCK‐B‐receptor‐positive tumors by fluorescence imaging.     

Effect of recombinant platelet-activating factor acetylhydrolase on two models of experimental acute pancreatitis

BACKGROUND & AIMS: Recent reports suggest that platelet-activating factor (PAF) plays a role in pancreatitis and pancreatitis-associated lung injury. In this study, the effects on these processes of termination of PAF action by recombinant PAF-acetylhydrolase (rPAF-AH) were investigated. METHODS: Rats were given rPAF-AH and then infused with a supramaximally stimulating dose of cerulein to induce mild pancreatitis. Opossums underwent biliopancreatic duct ligation to induce severe pancreatitis, and rPAF-AH administration was begun 2 days later. RESULTS: In mild, secretagogue-induced pancreatitis, rPAF-AH given before the cerulein reduced hyperamylasemia, acinar cell vacuolization, and pancreatic inflammation but did not alter pancreatic edema or pulmonary microvascular permeability. In severe, biliopancreatic duct ligation-induced pancreatitis, rPAF-AH delayed and reduced the extent of inflammation and acinar cell injury/necrosis and completely prevented lung injury even though the rPAF-AH administration was begun after the onset of pancreatitis. CONCLUSIONS: PAF plays an important role in the regulation of pancreatic injury but not pancreatic edema or increased pulmonary microvascular permeability in mild, secretagogue-induced pancreatitis. PAF plays a critical role in the regulation of progression of pancreatic injury and mediation of pancreatitis-associated lung injury in severe biliary pancreatitis. Amelioration of pancreatitis and prevention of pancreatitis-associated lung injury can be achieved with rPAF-AH even if treatment is begun after pancreatitis is established.     

On-chip testing of random access memories

This article gives an overview of the Built-In Self-Test techniques for stand alone Random-Access Memory chips. It identifies the limitations of the existing fault models and the test algorithms used to test large RAMs. Methods to reduce test time for testing large RAMs are categorized. The article argues that even linear time test algorithms must use architecture and design for testability induced parallelisms to keep the total test time to an acceptable limit. Following that two algorithms are presented that can be used to test large RAMs for neighborhood pattern sensitive faults. Test lengths and test time for application of these algorithms are computed and it is suggested that a microprogrammed controller based scheme be used to implement self-test in stand alone RAMs.Part of this work was completed when the author was a Visting Professor at the University of Roorkee, India.     

Improved test generation for high-activity circuits

An implementation of a test-pattern generator based on the Podem (path-oriented decision-making) algorithm is proposed. Podem uses a depth-first search from the fault location to assign primary input values. The result of these assignments at internal nodes is then determined by logic simulation (implication). Podem must compute primary input combinations that both excite the fault and propagate it to primary outputs. The algorithm can be improved for high-activity circuits by packing more than one signal value into a word during implication. Packing introduces parallelism into the implication part of test generation and can be used to examine both the normal assignment and the alternative assignment to an input variable in parallel. With parallelism, the input space can be searched faster. To assess the benefits of such a scheme, compiled-code and event-driven version of the `imply' function in Podem were implemented with and without the parallelism offered by value packing. Results show that conventional Podem with event-driven implication performs better for low-activity circuits, whereas Podem with compiled code and packed signal values performs better for high-activity circuits     

Online discriminative learning for machine translation with binary-valued feedback

Viewing machine translation (MT) as a structured classification problem has provided a gateway for a host of structured prediction techniques to enter the field. In particular, large-margin methods for discriminative training of feature weights, such as the structured perceptron or MIRA, have started to match or exceed the performance of existing methods such as MERT. One issue with these problems in general is the difficulty in obtaining fully structured labels, e.g. in MT, obtaining reference translations or parallel sentence corpora for arbitrary language pairs. Another issue, more specific to the translation domain, is the difficulty in online training and updating of MT systems, since existing methods often require bilingual knowledge to correct translation outputs online. The problem is an important one, especially with the usage of MT in the mobile domain: in the process of translating user inputs, these systems can also receive feedback from the user on the quality of the translations produced. We propose a solution to these two problems, by demonstrating a principled way to incorporate binary-labeled feedback (i.e. feedback on whether a translation hypothesis is a “good” or understandable one or not), a form of supervision that can be easily integrated in an online and monolingual manner, into an MT framework. Experimental results on Chinese–English and Arabic–English corpora for both sparse and dense feature sets show marked improvements by incorporating binary feedback on unseen test data, with gains in some cases exceeding 5.5 BLEU points. Experiments with human evaluators providing feedback present reasonable correspondence with the larger-scale, synthetic experiments and underline the relative ease by which binary feedback for translation hypotheses can be collected, in comparison to parallel data.     

Non-destructive Investigation of Paintings on Canvas by Continuous Wave Terahertz Imaging and Flash Thermography

Terahertz (THz) imaging is increasingly used in the cultural heritage field. In particular, continuous wave (CW) and low frequency THz is attracting more attention. The first application of the THz technique inherent to the cultural heritage field dates back 10 years ago. Since 2006, tangible improvements have been conducted in the refinement of the technique, with the aim to produce clear maps useful for any art restorer. In this paper, a CW THz (0.1 THz) imaging system was used to inspect paintings on canvas both in reflection and in transmission modes. In particular, two paintings were analyzed: in the first one, similar materials and painting execution of the original artwork were used, while in the second one, the canvas layer is slightly different. Flash thermography was used herein together with the THz method in order to observe the differences in results for the textile support materials. A possible application of this method for the detection of artwork forgery requires some parameterization and analysis of various materials or thickness influence which will be addressed in a future study. In this work, advanced image processing techniques including principal component thermography (PCT) and partial least squares thermography (PLST) were used to process the infrared data. Finally, a comparison of CW THz and thermographic results was conducted.     

Calibrating On-chip Thermal Sensors in Integrated Circuits: A Design-for-Calibration Approach

With the scaling of technology, thermal issues have started to adversely affect reliability, performance, and robustness of integrated circuits. As a result, many recent research papers have focused on the use of embedded thermal sensors to monitor the temperature profile within the IC and manage the on-chip resources to keep the temperatures within acceptable limits. However, due to increasing process variations and parameter drifts, temperature measurements by these thermal sensors may not be accurate unless these on-chip sensors are calibrated before shipping the devices to the users. Existing calibration methods are either time-consuming or assume that the sensors do not require calibration for they use very large area which makes them insensitive to variations and drifts. In this paper, we propose a design-for-calibration (DFC) approach for calibrating the embedded thermal sensors in the manufacturing environment. Simulation results demonstrate the effectiveness and accuracy of our approach. The impact of uncertainties in parameters on the accuracy of calibration is also investigated in the paper.