Jack Tan

Duke-NUS Graduate Medical School, Cardiology, Faculty Member

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Papers by Jack Tan

Techniques for addressing the Year 2000 transition

Proceedings Twenty-First Annual International Computer Software and Applications Conference (COMPSAC'97)

Abstract Most programs written in the past will be encountering the Year 2000 transition problem ... more

Performance evaluation of fault-tolerant routing on star networks

Proceedings of IEEE Scalable High Performance Computing Conference

In this paper, we present a new theoretical approach for studying the behaviour and the performan... more In this paper, we present a new theoretical approach for studying the behaviour and the performance of shortest paths fault-tolerant distributed algorithms of a certain class. The behaviour of each processor is modeled by means of a stochastic matrix. We show that achieving the optimal behaviour of N processors is equivalent to solvingan optimization problem of a function of 2N variables under constraints; this function is neither convex nor concave. Solutions for which such a type of algorithms has an optimal behaviour are derived. Using that result, we build a fuzzy set of solutions which provides a global overview (a sort of "relief"): each solution of the fuzzy set has value q ranging between 0 and 1, which may be regarded as its "bench-mark so (1q) points out the proximity of any solution from the optimal solution.

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Design and analysis of fault-tolerant star networks

Proceedings of the 1997 International Conference on Parallel Processing (Cat. No.97TB100162)

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Efficient implementation strategies for the DRB approach in fault-tolerant hypercubes

Proceedings Twenty-First Annual International Computer Software and Applications Conference (COMPSAC'97)

Abstract The distributed recovery block (DRB) is an efficient approach for the uniform treatment ... more

Multiple protocol network integration: a case study in internetworking with IP/IPX

[1992] Proceedings 17th Conference on Local Computer Networks

ABSTRACT

A parallel processing paradigm for wavelength division multiplexed networks

The implementation of a widely distributed multicomputer system for performing medium- and high-g... more The implementation of a widely distributed multicomputer system for performing medium- and high-grain parallel computations is described. An n-cube hypercube is embedded in a ring with 2n nodes using the Gray code scheme. Wavelength division multiplexing (WDM) fiber optic networks are used to crate the n direct connections between nodes not adjacent to each other

Ex vivo differentiation of human adult bone marrow stem cells into cardiomyocyte-like cells

Biochemical and Biophysical Research Communications, 2004

Bone marrow mesenchymal stem cells have been shown to transdifferentiate into cardiomyocytes afte... more Bone marrow mesenchymal stem cells have been shown to transdifferentiate into cardiomyocytes after 5-azacytidine treatment or co-culturing with rodent cardiomyocytes. We investigate if adult human bone marrow stem cells can be differentiated ex vivo into cardiomyocyte-like cells (CLCs) independent of cytotoxic agents or co-culturing technique. Sternal bone marrow was collected from 16 patients undergoing coronary artery bypass surgery. Mesenchymal stem cells were differentiated in a cardiomyogenic differentiation medium containing insulin, dexamethasone, and ascorbic acid. Differentiation towards CLCs was determined by induced expression of cardiomyocyte-specific proteins. Differentiated CLCs expressed multiple structural and contractile proteins that are associated with cardiomyocytes. Thin filament associated myofibrillar proteins were detected early in the cells, with cardiac troponin I, sarcomeric tropomyosin, and cardiac titin among the first expressed. Some CLCs were found to develop into a nascent cardiomyocyte phenotype with cross-striated myofibrils characterized by a-actinin-positive Z bands after 4-5 passages in differentiated culture. These lineage-defined CLCs may be potentially useful for repairing damaged myocardium.

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Abstracting Low-Level Network Programming With ACE, a Pattern-Oriented Network Programming Framework

Abstract—Network protocols such as the File Transfer Protocol (FTP) have been vital to the succes... more Abstract—Network protocols such as the File Transfer Protocol (FTP) have been vital to the success of the Internet. Network operating systems have developed APIs to allow application programmers to easily implement these protocols. The most popular API in usage today is the BSD Sockets API. This API provides low-level operations for performing connection establishment, message transmission and reception and provides ways to configure various low-level network parameters. However, this low-level API forces ...

Acoustic Surveillance of Physically Unmodified PCs

Proceedings of Security and Management, Jun 1, 2006

Abstract—Computer equipment produces a wide range of emanations in the visible, electromagnetic, ... more Abstract—Computer equipment produces a wide range of emanations in the visible, electromagnetic, and acoustic spectra. It is well known that electromagnetic emanations can reveal information about the operations being performed by a machine, and it has recently been shown that acoustic emanations can do the same. Additionally, techniques have been developed to manipulate electromagnetic emanations so that they surreptitiously transmit data to a remote receiver. In this paper, we similarly demonstrate how acoustic ...

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Parallelism in database production systems

[1990] Proceedings. Sixth International Conference on Data Engineering

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On the construction of efficient match networks

Proceedings of the 1992 ACM/SIGAPP Symposium on Applied computing technological challenges of the 1990's - SAC '92, 1992

The performance of rule based systems are limited by the multiple pattern multiple object (MPMO) ... more The performance of rule based systems are limited by the multiple pattern multiple object (MPMO) matching problem. Various efficiency heuristics have been applied manually to speedup the solutions to MPMO. We address the problem of automatically determining the best match network for rule matching. We contribute simple conditions to guarantee the optimality of given network in presence of updates to the working memory.

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PARTES: A partitioning scheme for parallel matching

Proceedings of 1993 IEEE Conference on Tools with Al (TAI-93)

We focus on the partitioning of rules for parallel matching in a production system. Our approach,... more We focus on the partitioning of rules for parallel matching in a production system. Our approach, called PARTES, applies the man-cut technique t o a Dataflow Discrimination Network (DDN) that represents th? antecedents of the rules. Our goal is t o rnaxiinize sharing of memory nodes within a partition while minimizing duplication of nodes across partitions. We illustrate the technique using a cost model based on shared memory nodes defined in a DDN created by the R E T E algorithin. A generalization t o any other algorithm utilizing a DDN as straightforward. We provide a performance analysis to show the effectiveness of PARTES.

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Exploring security vulnerabilities by exploiting buffer overflow using the MIPS ISA

ACM SIGCSE Bulletin, 2003

By exploiting a well known security vulnerability in many C library implementations, it is possib... more By exploiting a well known security vulnerability in many C library implementations, it is possible for an unprivileged user to gain unrestricted system privileges. With an understanding of how the process execution stack is allocated and managed during process execution, a user can override the return address of a C library routine and thereby resume execution at a different address where a set of malicious functions can be invoked [1]. This is known as the buffer overflow exploit. With buffer overflow as the underlying theme, an example will be described using C and the MIPS assembly language that simultaneously exposes students to issues in computer security, operating systems concepts such as memory management and function invocation/return, and the MIPS instruction set architecture.

The use of multiple displacement amplification to amplify complex DNA libraries

Nucleic Acids Research, 2008

Complex libraries for genomic DNA and cDNA sequencing analyses are typically amplified using bact... more Complex libraries for genomic DNA and cDNA sequencing analyses are typically amplified using bacterial propagation. To reduce biases, large numbers of colonies are plated and scraped from solid-surface agar. This process is time consuming, tedious and limits scaling up. At the same time, multiple displacement amplification (MDA) has been recently developed as a method for in vitro amplification of DNA. However, MDA has no selection function for the removal of ligation multimers. We developed a novel method of briefly introducing ligation reactions into bacteria to select single insert DNA clones followed by MDA to amplify. We applied these methods to a Gene Identification Signatures with Paired-End diTags (GIS-PET) library, which is a complex transcriptome library created by pairing short tags from the 5' and 3' ends of cDNA fragments together, and demonstrated that this selection and amplification strategy is unbiased and efficient.

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Multiplex sequencing of paired-end ditags (MS-PET): a strategy for the ultra-high-throughput analysis of transcriptomes and genomes

Nucleic Acids Research, 2006

The paired-end ditagging (PET) technique has been shown to be efficient and accurate for large-sc... more The paired-end ditagging (PET) technique has been shown to be efficient and accurate for large-scale transcriptome and genome analysis. However, as with other DNA tag-based sequencing strategies, it is constrained by the current efficiency of Sanger technology. A recently developed multiplex sequencing method (454-sequencing TM) using picolitrescale reactions has achieved a remarkable advance in efficiency, but suffers from short-read lengths, and a lack of paired-end information. To further enhance the efficiency of PET analysis and at the same time overcome the drawbacks of the new sequencing method, we coupled multiplex sequencing with paired-end ditagging (MS-PET) using modified PET procedures to simultaneously sequence 200 000 to 300 000 dimerized PET (diPET) templates, with an output of nearly half-a-million PET sequences in a single 4 h machine run. We demonstrate the utility and robustness of MS-PET by analyzing the transcriptome of human breast carcinoma cells, and by mapping p53 binding sites in the genome of human colorectal carcinoma cells. This combined sequencing strategy achieved an approximate 100-fold efficiency increase over the current standard for PET analysis, and furthermore enables the short-read-length multiplex sequencing procedure to acquire paired-end information from large DNA fragments.

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Food and Drug Administration–approved Endovascular Repair Devices for Abdominal Aortic Aneurysms: A Review

Journal of Vascular and Interventional Radiology, 2008

Endovascular treatment of infrarenal abdominal aortic aneurysm (AAA) offers a less invasive alter... more Endovascular treatment of infrarenal abdominal aortic aneurysm (AAA) offers a less invasive alternative to conventional open repair. Currently, only four devices are Food and Drug Administration (FDA)-approved for use in endovascular aneurysm repair (EVAR) of AAA in the United States. All four devices are associated with a high technical success rate and less morbidity than open surgical repair. Each device has its inherent design advantages and disadvantages that must be matched with patient and AAA characteristics. This review will discuss and compare the technology and procedural outcomes data of the current FDA-approved EVAR devices.

The Use of Bare-Metals Stents in Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction: Is There a Difference in Clinical Outcome Between Cobalt Chromium Versus Stainless Steel Stents?

Journal of the American College of Cardiology, 2010

Background: The use of DES results in lower risk of target vessel revascularization (TVR) compare... more Background: The use of DES results in lower risk of target vessel revascularization (TVR) compared to bare metal stents (BMS) following primary PCI for patients with acute ST-elevation myocardial infarction (STEMI). However, BMS are more commonly implanted compared to DES due to concerns of poor compliance to dual antiplatelet therapy, risk of late stent thrombosis and increased cost. Newer generation BMS based on cobalt chromium alloy have thinner stent struts, better deliverability and potentially lower rates of TVR compared with conventional stainless steel BMS. Therefore we aim to determine the clinical outcome and rates of TVR in patients undergoing primary PCI for STEMI who were treated with cobaltchromium stents compared to stainless steel stents. Methods: Prospective data on consecutive patients undergoing primary PCI for STEMI between 2002 and 2008 who were treated with BMS were collected. Baseline characteristics and data were obtained from medical records or telephone follow-up. Primary outcome was combined major adverse cardiovascular events (MACE) of all-cause death, nonfatal MI and clinically-driven TVR at six months. Results: 1353 patients (84% males) with mean age of 59±12 years were analysed. Overall procedural success rate was 98%. Stainless steel stents were inserted in 75% of patients (stainless steel, n=1014 vs cobalt chromium, n=339). There were no significant differences in age, gender, hypertension, hyperlipidemia, diabetes mellitus, smoking history and ethnicity between the two groups (p=ns). Usage of glycoprotein-IIbIIIa inhibitors or distal embolic protective devices during PCI was similar between the two groups (p=ns). There was no significant difference in overall MACE at 6 months between the stainless steel or cobalt chromium groups (8.2% vs 10.6%, p=0.17). The incidence of TVR after six months was 4.7% in the stainless steel group and 5.9% in the cobalt chromium group (p=0.40). Conclusions: In this observational analysis of patients undergoing primary PCI for STEMI who were treated with BMS, the overall MACE was similar at 6-months. In particular, both cobalt-chromium and stainless steel stents were associated with similar rates of clinically-driven TVR.

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TBSAM: an access method for efficient processing of statistical queries

IEEE Transactions on Knowledge and Data Engineering, 1989

The domain of statistical and scientific databases is targeted here, and the class of aggregate q... more The domain of statistical and scientific databases is targeted here, and the class of aggregate queries which are very often encountered in this domain is considered. Such a query is aimed at retrieving some aggregate characteristics of the raw data. The tree-based statistics access method (TBSAM), which provides support for the efficient processing of aggregate queries, is presented. It is

Performance analysis of a fault-tolerant B-tree ATM switch

… 1996., Proceedings 21st IEEE Conference on, 1996

The asynchronous transfer mode (ATM) has become the subject of intense interest across all segmen... more

Trans-pleural pericardiocentesis: Revisiting an old technique

Catheterization and Cardiovascular Interventions, 2011

Percutaneous access to the pericardial space serves both diagnostic and therapeutic purposes. Mul... more Percutaneous access to the pericardial space serves both diagnostic and therapeutic purposes. Multiple approaches have been described, which include the apical, subxiphoid, trans-atrial, and trans-bronchial techniques. Occasionally, in the presence of both left pleural effusion and posterior pericardial effusion, echocardiographically guided pleuropericardial drainage can be carried out using the left axillary approach. Here we revisit the use of this technique in a patient. Future development of this technique, using a noncompliant balloon to expand the pleuropericardial interface, may avoid the need for a pericardial window in oncology and rheumatology patients with recurrent pericardial effusions. V

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