Privacy-preserving Identity Management System

Recently, a self-sovereign identity model has been researched actively as an alternative to the existing identity models such as a centralized identity model, federated identity model, and user-centric model. The self-sovereign identity model allows a user to have complete control of his identity. Meanwhile, the core component of the self-sovereign identity model is data minimization. The data minimization signifies that the extent of the exposure of user private identity should be minimized. As a solution to data minimization, zero-knowledge proofs can be grafted to the self-sovereign identity model. Specifically, zero-knowledge Succinct Non-interactive ARgument of Knowledges(zk-SNARKs) enables proving the truth of the statement on an arbitrary relation. In this paper, we propose a privacy-preserving self-sovereign identity model based on zk-SNARKs to allow any type of data minimization beyond the selective disclosure and range proof. The security of proposed model is formally proven under the security of the zero-knowledge proof and the unforgeability of the signature in the random oracle model. Furthermore, we optimize the proving time by checking the correctness of the commitment outside of the proof relation for practical use. The resulting scheme improves proving time for hash computation (to verify a commitment input) from 0.5 s to about 0.1 ms on a 32-bit input

SIMS : Self Sovereign Identity Management System with Preserving Privacy in Blockchain

Blockchain, which is a useful tool for providing data integrity, has emerged as an alternative to centralized servers. Concentrating on the integrity of the blockchain, many applications have been developed. Specifically, a blockchain can be utilized in proving the user\u27s identity using its strong integrity. However, since all data in the blockchain is publicly available, it can cause privacy problems if the user\u27s identity is stored in the blockchain unencrypted. Although the encryption of the private information can diminish privacy problems in the blockchain, it is difficult to transparently utilize encrypted user information in the blockchain. To provide integrity and privacy of user information simultaneously in the blockchain, we propose a SIMS (Self-Sovereign Identity Management System) framework based on a zk-SNARK (zero-knowledge Succinct Non-interactive ARgument of Knowledge). In our proposed SIMS, the user information is employed in a privacy-preserving way due to the zero-knowledge property of the zk-SNARK. We construct a SIMS scheme and prove its security. We describe applications of SIMS and demonstrate its practicality through efficient implementations

Epidemics of enterovirus infection in Chungnam Korea, 2008 and 2009

Previously, we explored the epidemic pattern and molecular characterization of enteroviruses isolated in Chungnam, Korea from 2005 to 2006. The present study extended these observations to 2008 and 2009. In this study, enteroviruses showed similar seasonal prevalent pattern from summer to fall and age distribution to previous investigation. The most prevalent month was July: 42.9% in 2008 and 31.9% in 2009. The highest rate of enterovirus-positive samples occurred in children < 1-year-old-age. Enterovirus-positive samples were subjected to sequence determination of the VP1 region, which resolved the isolated enteroviruses into 10 types in 2008 (coxsackievirus A4, A16, B1, B3, echovirus 6, 7, 9, 11, 16, and 30) and 8 types in 2009 (coxsackievirus A2, A4, A5, A16, B1, B5, echovirus 11, and enterovirus 71). The most prevalent enterovirus serotype in 2008 and 2009 was echovirus 30 and coxsackievirus B1, respectively, whereas echovirus 18 and echovirus 5 were the most prevalent types in 2005 and 2006, respectively. Comparison of coxsackievirus B1 and B5 of prevalent enterovirus type in Korea in 2009 with reference strains of each same serotype were conducted to genetic analysis by a phylogenetic tree. The sequences of coxsackievirus B1 strains segregated into four distinct clusters (A, B, C, and D) with some temporal and regional sub-clustering. Most of Korean coxsackievirus B1 strains in 2008 and 2009 were in cluster D, while only "Kor08-CVB1-001CN" was cluster C. The coxsackievirus B5 strains segregated in five distinct genetic groups (clusters A-E) were supported by high bootstrap values. The Korean strains isolated in 2001 belonged to cluster D, whereas Korean strains isolated in 2005 and 2009 belonged to cluster E. Comparison of the VP1 amino acid sequences of the Korean coxsackievirus B5 isolates with reference strains revealed amino acid sequence substitutions at nine amino acid sequences (532, 562, 570, 571, 576-578, 582, 583, and 585)

Towards maximized volumetric capacity via pore-coordinated design for large-volume-change lithium-ion battery anodes

To achieve the urgent requirement for high volumetric energy density in lithium-ion batteries, alloy-based anodes have been spotlighted as next-generation alternatives. Nonetheless, for the veritable accomplishment with regards to high-energy demand, alloy-based anodes must be evaluated considering several crucial factors that determine volumetric capacity. In particular, the electrode swelling upon cycling must be contemplated if these anodes are to replace conventional graphite anodes in terms of volumetric capacity. Herein, we propose macropore-coordinated graphite-silicon composite by incorporating simulation and mathematical calculation of numerical values from experimental data. This unique structure exhibits minimized electrode swelling comparable to conventional graphite under industrial electrode fabrication conditions. Consequently, this hybrid anode, even with high specific capacity (527 mAh g(-1)) and initial coulombic efficiency (93%) in half-cell, achieves higher volumetric capacity (493.9 mAh cm(-3)) and energy density (1825.7 Wh L-1) than conventional graphite (361.4 mAh cm(-3) and 1376.3 Wh L-1) after 100 cycles in the full-cell configuration

Replacing conventional battery electrolyte additives with dioxolone derivatives for high-energy-density lithium-ion batteries

Solid electrolyte interphases generated using electrolyte additives are key for anode-electrolyte interactions and for enhancing the lithium-ion battery lifespan. Classical solid electrolyte interphase additives, such as vinylene carbonate and fluoroethylene carbonate, have limited potential for simultaneously achieving a long lifespan and fast chargeability in high-energy-density lithium-ion batteries (LIBs). Here we report a next-generation synthetic additive approach that allows to form a highly stable electrode-electrolyte interface architecture from fluorinated and silylated electrolyte additives; it endures the lithiation-induced volume expansion of Si-embedded anodes and provides ion channels for facile Li-ion transport while protecting the Ni-rich LiNi0.8Co0.1Mn0.1O2 cathodes. The retrosynthetically designed solid electrolyte interphase-forming additives, 5-methyl-4-((trifluoromethoxy)methyl)-1,3-dioxol-2-one and 5-methyl-4-((trimethylsilyloxy)methyl)-1,3-dioxol-2-one, provide spatial flexibility to the vinylene carbonate-derived solid electrolyte interphase via polymeric propagation with the vinyl group of vinylene carbonate. The interface architecture from the synthesized vinylene carbonate-type additive enables high-energy-density LIBs with 81.5% capacity retention after 400 cycles at 1???C and fast charging capability (1.9% capacity fading after 100 cycles at 3???C)

Frailty Related to the Exposure to Particulate Matter and Ozone: The Korean Frailty and Aging Cohort Study

This study aims to identify the association between the concentration of particulate matter &lt;2.5 μm (PM2.5), &lt;10 μm (PM10), and ozone (O3) and frailty. The Korean Frailty Scale (KFS, 0–6 points) assessing physical, psychological, and social frailty, was applied to 2912 community-dwelling older adults between April 2016 and December 2017. Daily average concentrations of PM2.5, PM10, and O3 (2015–2017) were obtained and matched with the residential areas. The frailty risk associated with exposure to PM2.5, PM10, and O3 was evaluated using multiple logistic regression after adjusting for age, sex, BMI, lifestyle, socioeconomic status, and comorbidity. Participants were categorized into robust (0 points, 28.7%), pre-frail (1–2 points, 50.1%), and frail (≥3 points, 21.2%) groups. Each 1 μg/m3 increase of PM2.5 and PM10 increased the odds ratios (ORs) and 95% confidence intervals (CIs) of the frail group compared to the robust group: 1.055 (1.002, 1.112) and 1.095 (1.060, 1.131), and the pre-frail group: 1.053 (1.017, 1.090) and 1.062 (1.037, 1.087), respectively. Each 1-ppb increase of O3 increased the OR (95% CI) of the frail group: 1.041 (1.023, 1.059) and the pre-frail group: 1.005 (0.985, 1.025). PM2.5, PM10, and O3 may be associated dose-dependently with the frailty

High Performance IoT Cloud Computing Framework Using Pub/Sub Techniques

The Internet of Things is attracting attention as a solution to rural sustainability crises, such as slowing income, exports, and growth rates due to the aging of industries. To develop a high-performance IoT platform, we designed and implemented an IoT cloud platform using pub/sub technologies. This design reduces the difficulty of overhead for management and communication, despite the harsh IoT environment. In this study, we achieved high performance by applying the pub/sub platform with two different characteristics. As the size and frequency of data acquired from IoT nodes increase, we improved performance through MQTT and Kafka protocols and multiple server architecture. MQTT was applied for fast processing of small data, and Kafka was applied for reliable processing of large data. We also mounted various sensors and actuators to measure the data of growth for each device using the protocol. For example, DHT11, MAX30102, WK-ADB-K07-19, SG-90, and so on. As a result of performance evaluation, the MQTT Kafka platform implemented in this research was found to be effective for use in environments where network bandwidth is limited or a large amount of data is continuously transmitted and received. We realized the performance as follows: the response time for user requests was measured to be within 100 ms on average, data transmission order verification for more than 13 million requests, data processing performance per second on an average of 113,134.89 record/s, and 64,313 requests per second were performed for requests that occurred simultaneously from multiple clients

Exposure to Ambient Air Pollution and Cognitive Impairment in Community-Dwelling Older Adults: The Korean Frailty and Aging Cohort Study

The aim of this study was to investigate the associations between ambient air pollutants and cognitive impairment in Korean older adults. The cognitive function of 2,896 participants aged 70 to 84 years was measured using the Korean version of the mini-mental state examination, the digit span test, the word list learning test, and the frontal assessment battery. After matching the average concentrations of particulate matter (PM) &lt;10 &mu;m in size (PM10) and &lt;2.5 &mu;m (PM2.5), NO2, CO, SO2, and O3 between 2013 and 2017, the association between air pollutants and cognitive scales was analyzed using a linear mixed regression and a multiple logistic regression analysis (after adjusting for age, sex, health related behaviors, socioeconomic status, comorbidity, and meteorological data). Exposure to PM2.5, PM10, NO2, SO2, and CO was associated with cognitive impairment above and beyond age or education level effects. Specifically, PM2.5 was negatively associated with most components of the cognitive scales (interquartile range for PM2.5: 2.0 &mu;g/m3, odds ratio for poor global cognition: 2.28, 95% confidence interval: 1.60&ndash;3.26). These associations may be affected by sex, residence area, or alcohol intake. Conclusively, air pollutants, especially PM2.5, were associated with cognitive impairment, including global cognition, attention, memory, and executive function in Korean older adults aged &ge;70 years