Fault Diagnosis of Physical Defects Using Unknown Behavior Model

A new fault model, called the X-fault model, is proposed for fault diagnosis of physical defects with unknown behaviors by using X symbols. An efficient X-fault simulation method and an efficient X-fault diagnostic reasoning method are presented. Fault diagnosis based on the X-fault model can improve the accuracy of failure analysis for a wide range of physical defects in complex and deep submicron integrated circuits.     

Optimal Test Scheduling Formulation under Power Constraints with Dynamic Voltage and Frequency Scaling

As a consequence of technology scaling and increasing power consumption of modern high performance designs, various techniques, such as clock gating and Dynamic Voltage and Frequency Scaling (DVFS), have been adapted to address power issues. These techniques are important and desirable to address reliability needs as well as economic issues. From a testing point of view, the introduction of power constraints during testing is needed to achieve the desired product quality and to avoid yield loss. Unlike designers who have benefited from the Design-for-Test hardware introduced for testing, test engineers have rarely taken advantage of the extra hardware introduced to meet design needs. In this paper, we make use of the DVFS technology and its associated hardware to improve test economics. We formulate the power constrained testing problem as an optimization problem that makes use of DVFS technology. We show that superior test schedules can be obtained for both session-based and sessionless testing methods relative to existing and traditional methods of obtaining test schedules.     

Induction of apoptosis in pancreatic acinar cells reduces the severity of acute pancreatitis

1-Cyano-2-hydroxy-3-butene (CHB) has been reported to cause cell death in rat pancreatic acini. In this report, we describe the time-dependent effects of CHB on mouse acinar cell apoptosis and the effects of CHB-induced acinar cell apoptosis on the severity of secretagogue-induced acute pancreatitis in mice. CHB administration to mice resulted in a time-dependent increase in pancreatic apoptosis, which was maximal 12 hours after CHB administration. The severity of pancreatitis was significantly reduced by prior CHB administration and maximal protection was observed when the caerulein injections were started 12 hours after CHB administration. These observations indicate that induction of apoptosis can reduce the severity of pancreatitis and they suggest that induction of pancreatic acinar cell apoptosis may be beneficial in the clinical management of acute pancreatitis.     

Early ductal decompression prevents the progression of biliary pancreatitis: an experimental study in the opossum

BACKGROUND: The value of early endoscopic or surgical interventions to remove bile duct stones and decompress the biliopancreatic ductal system in gallstone pancreatitis is controversial. METHODS: To evaluate this issue, acute hemorrhagic necrotizing pancreatitis was induced in opossums by obstructing the biliopancreatic ductal system with a balloon catheter for 1, 3, or 5 days. RESULTS: A progressive increase in the severity of pancreatitis, as manifested by inflammation, fat necrosis, hemorrhage, acinar cell vacuolization, in vitro lactate dehydrogenase release, and acinar cell necrosis, was noted in these obstructed animals. In contrast, decompression of the obstructed ductal system by removal of the balloon catheter after 1 or 3 days prevented the increase in severity of these parameters of pancreatic injury. CONCLUSIONS: We concluded that the severity of biliary pancreatitis in this model is dependent upon the duration of ductal obstruction and that decompression of the ductal system can prevent progression of the disease. These observations support the practice of early attempts to remove obstructing stones in clinical gallstone pancreatitis.     

Testable design of large random access memories

In this paper we propose a method for testable design of large Random Access Memories. The design technique relies on modification of address decoders to achieve multi-writes and multi-reads during test mode. Almost no modification is required in the design of memory array.A number of different designs for decoders are proposed. In all the designs the objective has been to keep the extra hardware for enhancing testability to as small as possible while causing a minimal or no degradation at all in the speed performance of RAM. Use of extra control and observation points is allowed as long as such points cause only a very small increase in the number of extra pins.We also propose the design of decorders in which only a limited number of cells of RAM are written to or read from during test mode.     

Ultrasound echogenicity in experimental venous thrombosis

This study characterizes the echogenicity of experimentally induced venous thrombosis. Venous duplex imaging (Diasonics Spectra) was performed of the rat (n 12) and primate (n 3) inferior vena cava (IVC). Thrombosis was induced by IVC ligation at the level of the renal veins (rat, baboon) or balloon occlusion (baboon) of the IVC at the renal vein and iliac vein bifurcation level. Sham-treated rats served as controls. B-mode images were stored for off-line computer analysis. Fixed depth gain control curves allowed for measuring gain-corrected echogenicity units over the IVC in both a longitudinal and transverse orientation. In rat studies, thrombus was removed at time of euthanasia and dissolved, allowing for fibrin monomer determination using a chromogenic assay. Echogenicity values generally increased over time in both rat and primate studies. Significant differences between ligated and sham-treated rats were noted at each time point measured (6 h, 2 days, and 6 days after IVC ligation) and fibrin monomer values correlated (p < 0.05) with echogenicity units. In primate studies, echogenicity values significantly were different from baseline values at all time points measured (6 h, 2 days, 6 days, and 13 days after thrombus induction). Duplex ultrasound can be used to quantitate thrombus echogenicity, which correlates to fibrin content. Such measurement may potentially allow for improved thrombus age determination and the noninvasive quantitation of thrombus progression/resolution.     

A Heuristic Measure to Maximize Detected Faults per Test

In this paper we introduce a new measure for target fault selection and backtrace during test generation. The measure incorporates information on undetected faults and hence attempts to maximize the number of additional faults that may be detected by each test vector. Experimental results show the usefulness of this heuristic and demonstrate its superiority over the use of the SCOAP measure.     

Fault Models and Test Procedures for Flash Memory Disturbances

Disturbances are special type of faults that are unique to flash memories. Causes of the disturbances are defects within the insulating layers of the memory element. These defects result in abnormal behavior of a memory cell under specific conditions. This paper describes characteristics of these defects as well as their manifestation as DC-Programming, DC-Erasure, and Drain Disturbance. We develop fault models to capture the behavior of faulty flash memories. We introduce three different fault models based on the underlying defects in a memory cell. These models are: Simple, Exclusive and General Fault model. Further, we develop test algorithms that detect disturbance faults under each of the fault models. The test algorithms reported in this paper for the simple fault model for each type of disturbance require optimal number of program, read, and flash operations; where as the algorithms for the remaining two fault models require near optimal number of these operations.