Study on probabilistic and computational approaches to risk modeling, analysis and forecasting

Scope and Method of Study: A statistically-based yet probabilistically-concluded and computationally-implemented approach to modeling and evaluation of likelihood for events of interest to occur with a focus on risky events.Findings and Conclusions: This study introduces a method that can facilitate the extension of the Multiple Regression with Dependent Dummy Variable (MRDDV) Model to provide a way of estimating the likelihood of any event of concern by probability. MRDDV employs a dependent dummy variable in its regression model as primary inputs for estimation. However, MRDDV is not proper to provide a probability-based estimator because it violates the definition of probability. To overcome this, a method, namely Logit Transformation, is employed to facilitate the probabilistic manipulation of MRDDV. By using Logit Transformation, the estimation of risk in MRDDV is, stably, represented in probabilistic domain (e.g., in the range beyond 0 or 1). Simulation results showed that Logit Transformation-based MRDDV Model improved the basic scheme significantly. And, a user's risk defining system is, also, introduced. The enhanced Logit Transformation-based MRDDV Model is probabilistic and robust in risk tracking

Reliability Modeling and Analysis of Clockless Wave Pipeline Core for Embedded Combinational Logic Design

This paper presents a model for analyzing the reliability of a clockless wave pipeline as an intellectual property (IP) core for embedded design. This design requires different clocking requirements by each embedded IP core during integration. Therefore, either partial or global lack of synchronization of the embedded clocking is considered for the data flow. The clockless wave pipeline represents an alternative to a traditional pipeline scheme; it requires an innovative computing model that is readily suitable for high-throughput computing by heterogeneous IP logic cores embedded in system-on-chip (SoC). A clockless wave pipeline technique relies on local asynchronous operation for seamless integration of a combinational core into an SoC. The basic computational components of a clockless wave pipeline are the datawaves, together with the request signals and switches. The coordination of the processing of the datawaves throughout the pipeline by the request signals is accomplished with no intermediate access in the clock control. Furthermore, the reliability of clockless-wave-pipeline-based cores is of importance when designing a reliable SOC. In this paper, the reliability in the clockless operations of the wave pipeline is analyzed by considering the datawaves and the request signals. The effect of the so-called out-of-orchestration between the datawaves and the request signals (which is referred to as a datawave fault) is proposed in the reliability analysis. A clockless-induced datawave fault model is proposed for clockless fault-tolerant design

Reduction of metabolic waste products, ammonia and lactate, through the coupling of GS selection and LDH-A down-regulation in CHO cells

The cultivation of Chinese hamster ovary (CHO) cells for the production of therapeutic proteins inevitably accompanies the production of metabolic wastes, mostly ammonia and lactate. Ammonia alters cell growth, productivity and the glycosylation patterns of proteins, and lactate acidifies culture media, having negative effects on cell culture. A stable CHO cell line should be established for the manufacturing process of therapeutic proteins, and the development of stable cell lines is usually based on two expression systems: the dihydrofolate reductase (DHFR) system and the glutamine synthetase (GS) system. Compared to the DHFR system, the GS system produces a reduced level of ammonia because the GS protein uses ammonia to produce glutamine. In order to overcome the lactate accumulation problem, down-regulation of the lactate-producing enzyme, lactate dehydrogenase-A (LDH-A), has been shown to be effective. Engineering of the LDH-A gene has been applied for several CHO cell lines with the DHFR system, but there has been no trial which couples the ammonia reduction from the GS system and lactate reduction through cell engineering. In the present study, the GS system was used for the expression of therapeutic antibody in CHO cells, thereby reducing ammonia in the culture media. In addition, the LDH-A gene was down-regulated with shRNA to reduce lactate production. The antibody-producing cell line produces a reduced level of ammonia compared to the host cell line due to the over-expression of the GS protein. The down–regulation of the LDH-A gene in the antibody-producing cell line not only reduces the level of lactate but also further reduces the level of ammonia, accomplishing complete waste reduction. LDH-A down-regulation was also applied to the host cell lines of the GS system – the CHO-K1 cell line and the GS deficient CHO-K1 cell line. However, LDH-A down-regulated host cells could not survive the pool-selection process. Given that the GS system uses a glutamine-depleted condition as a form of selection pressure, enhanced glycolysis is inevitable and the down-regulation of LDH-A appears to hinder metabolic changes. Taken together, the application of LDH-A down-regulation in the producing cell line of the GS system successfully reduced both ammonia and lactate levels. However, LDH-A engineering could not be applied to the host cell lines because it inhibits the selection process of the GS system

Medical Expenses of North Korean Defectors with Post-Traumatic Stress Disorder

Objective The purpose of this study was to establish the prevalence of PTSD among North Korean defectors who visited the National Medical Center, Seoul, South Korea over a period of approximately 10 years by examining their medical records and to examine differences in the medical service usage patterns of patients with and without PTSD. Methods Data from North Korean defectors who used outpatient services at the National Medical Center during a period of 10 years and 3 months (January 1 2006 to February 28, 2016) were analyzed. The general characteristics of the defectors were analyzed by frequency analyses, and descriptive statistics were generated. Additionally, independent t-tests and chi square analyses were performed to examine differences between PTSD patients and those without PTSD. Linear regression analysis was performed to examine factors affecting the mental health of North Korean defectors suffering from PTSD. Results This study assessed the correlations between PTSD, the average number of outpatient visits, and the total revenue. The regression analysis showed a relationship between PTSD and the average number of outpatient visits. There was also a correlation between PTSD and total revenue. The average number of outpatient visits was 41.8 for PTSD patients, whereas it was 33.2 for those without PTSD. The. total revenue visit was 953.6 USD for PTSD sufferers and 231.1 USD for those without PTSD. Conclusion This study found that the majority of North Korean defectors visit psychiatry departments, and that PTSD patients use outpatient services more frequently and have higher total revenue than those without PTSD. Additionally, patients with PTSD used a greater variety of medical services. Considering the high medical care expenses of North Korean defectors residing in South Korea, future investigations should examine the medical service usage patterns of such patients, especially those diagnosed with PTSD, in greater detail

Energy-Based Models for Anomaly Detection: A Manifold Diffusion Recovery Approach

We present a new method of training energy-based models (EBMs) for anomaly detection that leverages low-dimensional structures within data. The proposed algorithm, Manifold Projection-Diffusion Recovery (MPDR), first perturbs a data point along a low-dimensional manifold that approximates the training dataset. Then, EBM is trained to maximize the probability of recovering the original data. The training involves the generation of negative samples via MCMC, as in conventional EBM training, but from a different distribution concentrated near the manifold. The resulting near-manifold negative samples are highly informative, reflecting relevant modes of variation in data. An energy function of MPDR effectively learns accurate boundaries of the training data distribution and excels at detecting out-of-distribution samples. Experimental results show that MPDR exhibits strong performance across various anomaly detection tasks involving diverse data types, such as images, vectors, and acoustic signals.Comment: NeurIPS 202

The Effects of Discrimination Experience on Life Satisfaction of North Korean Refugees:Mediating Effect of Stress

Objective This study investigated the mediation effect of stress between the experience of discrimination and life satisfaction among North Korean refugees who resettled in South Korea. The findings of the current study provide empirical evidence for the need of social interventions to mitigate adverse effects of stress on North Korean refugees who are subject to social discrimination on a daily basis. Methods In this study, we included 500 subjects among 2,138 North Korean refugees who took refuge in South Korea in 2007. The interview started from April 6th 2009 and finished on May 25th 2009. We conducted moderator effect analysis with Path analysis was conducted because we confirm the experience of discrimination was affected by life satisfaction and stress can affected life satisfaction as a moderator. Results The experience of discrimination significantly affects stress and stress significantly affects life satisfaction. However, the experience of discrimination was not directly related to life satisfaction. The more stress the study respondents experienced, the lower the life satisfaction they reported. Conclusion The present finding suggests that the effects of discriminating experiences on the life satisfaction of North Korean refugees in South Korea were mediated by their own perceived stress

Effect of Information Disclosure Policy on Control of Infectious Disease:MERS-CoV Outbreak in South Korea

This study examined the effect of disclosing a list of hospitals with Middle East respiratory syndrome coronavirus (MERS-CoV) patients on the number of laboratory-confirmed MERS-CoV cases in South Korea. MERS-CoV data from 20 May 2015 to 5 July 2015 were from the Korean Ministry of Health & Welfare website and analyzed using segmented linear autoregressive error models for interrupted time series. This study showed that the number of laboratory-confirmed cases was increased by 14.629 on June 5 (p < 0.001). However, this number was significantly decreased following disclosure of a list of hospitals with MERS-CoV cases (Estimate = −0.948; p < 0.001). Disclosing the list of hospitals exposed to MERS-CoV was critical to the prevention of further infection. It reduced the number of confirmed MERS-CoV cases. Thus, providing accurate and timely information is a key to critical care response

Ruthenium anchored on carbon nanotube electrocatalyst for hydrogen production with enhanced Faradaic efficiency

Developing efficient and stable electrocatalysts is crucial for the electrochemical production of pure and clean hydrogen. For practical applications, an economical and facile method of producing catalysts for the hydrogen evolution reaction (HER) is essential. Here, we report ruthenium (Ru) nanoparticles uniformly deposited on multi-walled carbon nanotubes (MWCNTs) as an efficient HER catalyst. The catalyst exhibits the small overpotentials of 13 and 17 mV at a current density of 10 mA cm(-2) in 0.5M aq. H2SO4 and 1.0M aq. KOH, respectively, surpassing the commercial Pt/C (16 mV and 33 mV). Moreover, the catalyst has excellent stability in both media, showing almost &quot;zeroloss&quot; during cycling. In a real device, the catalyst produces 15.4% more hydrogen per power consumed, and shows a higher Faradaic efficiency (92.28%) than the benchmark Pt/C (85.97%). Density functional theory calculations suggest that Ru-C bonding is the most plausible active site for the HER