Edge- and Node-Disjoint Paths in P Systems

In this paper, we continue our development of algorithms used for topological network discovery. We present native P system versions of two fundamental problems in graph theory: finding the maximum number of edge- and node-disjoint paths between a source node and target node. We start from the standard depth-first-search maximum flow algorithms, but our approach is totally distributed, when initially no structural information is available and each P system cell has to even learn its immediate neighbors. For the node-disjoint version, our P system rules are designed to enforce node weight capacities (of one), in addition to edge capacities (of one), which are not readily available in the standard network flow algorithms.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

A Validation Study of the Korean Version of SPAN

Purpose: The SPAN, which is acronym standing for its four components: Startle, Physiological arousal, Anger, and Numbness, is a short post-traumatic stress disorder (PTSD) screening scale. This study sought to develop and validate a Korean version of the SPAN (SPAN-K). Materials and Methods: Ninety-three PTSD patients (PTSD group), 73 patients with non-psychotic psychiatric disorders (psychiatric control group), and 88 healthy participants (normal control group) were recruited for this study. Participants completed a variety of psychiatric assessments including the SPAN-K, the Davidson Trauma Scale (DTS), the Clinician-Administered PTSD Scale (CAPS), and the State-Trait Anxiety Inventory (STAI). Results: Cronbach's alpha and test-retest reliability values for the SPAN-K were both 0.80. Mean SPAN-K scores were 10.06 for the PTSD group, 4.94 for the psychiatric control group, and 1.42 for the normal control group. With respect to concurrent validity, correlation coefficients were 0.87 for SPAN-K vs. CAPS total scores (p<0.001) and 0.86 for SPAN-K vs. DTS scores (p<0.001). Additionally, correlation coefficients were 0.31 and 0.42 for SPAN-K vs. STAI-S and STAI-T, respectively. Receiver operating characteristic analysis of SPAN-K showed good diagnostic accuracy with an area under the curve (AUC) of 0.87. The SPAN-K showed the highest efficiency at a cutoff score of 7, with a sensitivity of 0.83, a specificity of 0.81, positive predictive value (PPV) of 0.88, and negative predictive value (NPV) of 0.73. Conclusion: These results suggest that the SPAN-K had good psychometric properties and may be a useful instrument for rapid screening of PTSD patients.This study was supported by a grant of the Korean Academy of Anxiety Disorders, Korean Neuropsychiatric Association, and Korean Research Foundation (2006-2005152), Republic of Korea

Psychometric Validation of the Korean Version of Structured Interview for Post-traumatic Stress Disorder (K-SIP)

For diagnosis and management of post-traumatic stress disorder (PTSD), the easily administered assessment tool is essential. Structured Interview for PTSD (SIP) is a validated, 17-item, simple measurement being used widely. We aimed to develop the Korean version of SIP (K-SIP) and investigated its psychometric properties. Ninety-three subjects with PTSD, 73 subjects with mood disorder or anxiety disorder as a psychiatric control group, and 88 subjects as a healthy control group were enrolled in this study. All subjects completed psychometric assessments that included the K-SIP, the Korean versions of the Clinician-Administered PTSD Scale (CAPS) and other assessment tools. The K-SIP presented good internal consistency (Cronbach's α=0.92) and test-retest reliability (r=0.87). K-SIP showed strong correlations with CAPS (r=0.72). Among three groups including PTSD patients, psychiatric controls, and normal controls, there were significant differences in the K-SIP total score. The potential cut-off total score of K-SIP was 20 with highest diagnostic efficiency (91.9%). At this point, the sensitivity and specificity were 95.5% and 88.4%, respectively. Our result showed that K-SIP had good reliability and validity. We expect that K-SIP will be used as a simple but structured instrument for assessment of PTSD

Throughput optimization for two-dimensional mesh and torus networks

Two dimensional networks constitute an important class of interconnection networks in both commercial and research machines. Minimizing latency and maximizing throughput are important design goals. In this thesis, I propose three techniques to improve the throughput achieved in two-dimensional mesh and torus networks. First, the routing algorithm may create an imbalance in the load on network links. Ideally, I would like a routing algorithm to (a) route packets using the minimal number of hops, (b) deliver good worst-case and average-case throughput, and (c) enable low-complexity router implementation. Existing routing algorithms fail to satisfy one or more of design goals mentioned above. We propose a new routing algorithm - O1TURN - satisfying all the stated design goals. Second, crossbar arbitration may underutilize free output ports and thus unnecessarily degrade throughput. The performance of crossbar arbitration depends on two metrics:(a) matching power, (b) arbitration throughput. Unfortunately, these two metrics are conflicting goals to achieve. I propose new crossbar arbitration mechanism - TabArb - that delivers superior matching and high arbitration throughput. It improves the saturation throughput by 14.8%. Third, I address network switching for streaming communication. Unfortunately, traditional packet-switched networks are not suitable for streaming communication. In packet-switching, each packet contends for resources as it traverses the network which can result in significant throughput degradation for streaming applications. I demonstrate a disjoint-path routing that ensures that streaming data has dedicated bandwidth. It improves the throughput of streaming applications by 55% on a 4x4 mesh network

Table-lookup based Crossbar Arbitration for Minimal-Routed, 2D Mesh and Torus Networks

Crossbar arbitration—which determines the allocation of output ports to packets in the input queues—is a performance-critical stage in the overall performance of routers for input-queued networks. The overall performance of crossbar arbitration depends on two metrics: (a) matching power – the ability of the arbiter to maximize the number of matches between requesting inputs and free outputs and (b) arbitration throughput – the number of such matches per unit time. Ideally, crossbar arbitration should maximize both metrics. Unfortunately, implementing high performance matching schemes compromises arbitration throughput. Similarly, simpler arbitration mechanisms that deliver high arbitration throughput offer lower matching power. The major contribution of this paper is the design of a tablelookup based crossbar arbitration mechanism—TabArb—that delivers superior matching and high arbitration throughput for minimal-routed, two dimensional mesh and torus networks. The two key innovations of TabArb are: (a) it forwards multiple requests from each input port to multiple output ports to expose adequate matching potential and (b) it employs precomputed tables that store maximum cardinality matches for all possible request combinations. Our technique improves the saturation throughput of adaptive routed mesh network by 14.8%. It offers little improvement for the DOR router due to limited opportunity.

Near-Optimal Worst-case Throughput Routing for Two-Dimensional Mesh Networks

Minimizing latency and maximizing throughput are important goals in the design of routing algorithms for interconnection networks. Ideally, we would like a routing algorithm to (a) route packets using the minimal number of hops to reduce latency and preserve communication locality, (b) deliver good worst-case and average-case throughput and (c) enable low-complexity (and hence, low latency) router implementation. In this paper, we focus on routing algorithms for an important class of interconnection networks: two dimensional (2D) mesh networks. Existing routing algorithms for mesh networks fail to satisfy one or more of design goals mentioned above. Variously, the routing algorithms suffer from poor worst case throughput (ROMM [13], DOR [24]), poor latency due to increased packet hops (VALIANT [32]) or increased latency due to hardware complexity (minimal-adaptive [7, 31])

Can Voice Reviews Enhance Trust in Voice Shopping? The Effects of Voice Reviews on Trust and Purchase Intention in Voice Shopping

Despite the high expectations of the voice shopping market, the impact of reviews and product types on voice commerce has yet to be explored. The purpose of this study is to investigate the effect of reviews and product types on users’ trust and purchase intentions in voice shopping. We explore users’ trust for voice shopping, trust in the vendor and purchase intention in three different types of reviews (i.e., no review, review by rating, and review by feature) and product types (i.e., search goods, experience goods, and convenience goods). We found that review conditions had a significant effect on purchase intentions and trust in voice shopping, whereas product types did not. Even within the review conditions, only the review by rating condition showed a significant difference from the no review condition. This study contributes to consumers and marketers by demonstrating the importance of providing rating reviews which requires a low cognitive load in the audio-centric environment

Sirtuin 1 attenuates nasal polypogenesis by suppressing epithelial-to-mesenchymal transition

Background: Nasal polyps (NPs) imply a refractory clinical course in patients with chronic rhinosinusitis (CRS). Previously, we showed that hypoxia-inducible factor (HIF) 1 could mediate nasal polypogenesis through epithelial-to-mesenchymal transition (EMT). Sirtuin 1 (SIRT1), a histone deacetylase, reportedly suppresses the transcriptional activity of HIF-1. Thus we hypothesized that SIRT1 attenuates nasal polyposis by inhibiting HIF-1-induced EMT. Objective: We sought to determine the role of SIRT1 in patients with nasal polyposis. Methods: The effects of SIRT1 on nasal polypogenesis were investigated in previously developed murine models. Immunohistochemistry, immunoblotting, and immunoprecipitation were done to evaluate SIRT1, EMT, and hypoxicmarkers in human nasal epithelial cells or sinonasal tissues from the mice and the patients with CRS with or without NPs. Results: SIRT1 transgenic mice had significantly fewer mucosal lesions with epithelial disruption and fewer NPs than wild-type (WT) mice. In addition, resveratrol (a SIRT1 activator) treatment suppressed nasal polypogenesis in WT mice; however, sirtinol (a SIRT1 inhibitor) administration increased the polyp burden in SIRT1 transgenic mice. In sinonasal specimens from patients with CRS, SIRT1 was downregulated in the mucosa from patients with polyps compared with levels seen in patients without polyps. SIRT1 overexpression or activation reversed hypoxia-induced EMT in human nasal epithelial cells. The intranasal transfection of a small hairpin SIRT1 lentiviral vector induced more nasal polypoid lesions in SIRT1 transgenic mice. Finally, mucosal extracts from patients with CRS without NPs increased SIRT1 expression in nasal epithelial cells, whereas those from patients with CRS with NPs did not. Conclusion: SIRT1 suppressed NP formation, possibly because of inhibition of HIF-1-induced EMT. Thus nasal epithelium SIRT1 might be a therapeutic target for NPs

Urine 5-Eicosatetraenoic Acids as Diagnostic Markers for Obstructive Sleep Apnea

Early detection of obstructive sleep apnea (OSA) is needed to reduce cardiovascular sequelae and mortality. Full-night polysomnography has been used for diagnosing OSA, but it is too expensive and inconvenient for patients to handle. Metabolome-wide analyses were performed to find and validate surrogate markers for OSA. We further investigated the mechanism underlying hypoxic induction of the markers in human cells and mice. Arachidonic acid derivatives 5-HETE and 5-oxoETE were detected in urine samples. The levels (mean ± SD, ng per mg creatinine) of 5-HETE and 5-oxoETE were 56.4 ± 26.2 and 46.9 ± 18.4 in OSA patients, respectively, which were significantly higher than those in controls (22.5 ± 4.6 and 18.7 ± 3.6). Both levels correlated with the apnea-hypopnea index and the lowest oxygen saturation on polysomnography. After the treatment with the continuous positive airway pressure, the metabolite levels were significantly reduced compared with those before the treatment. In human mononuclear cells subjected to intermittent hypoxia, 5-HETE and 5-oxoETE productions were induced by hypoxia-inducible factor 1 and glutathione peroxidase. When mice were exposed to intermittent hypoxia, 5-HETE and 5-oxoETE were excreted more in urine. They were identified and verified as new OSA markers reflecting hypoxic stress. The OSA markers could be used for OSA diagnosis and therapeutic evaluation