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Valence change-type resistance switching behaviors in oxides can be understood by well-established physical models describing the field-driven oxygen vacancy distribution change. In those models, electroformed residual oxygen vacancy filaments are crucial as they work as an electric field concentrator and limit the oxygen vacancy movement along the vertical direction. Therefore, their movement outward by diffusion is negligible. However, this situation may not be applicable in the electroforming-free system, where the field-driven movement is less prominent, and the isotropic oxygen vacancy diffusion by concentration gradient is more significant, which has not been given much consideration in the conventional model. Here, we propose a modified physical model that considers the change in the oxygen vacancies' charged state depending on their concentrations and the resulting change in diffusivity during switching to interpret the electroforming-free device behaviors. The model suggests formation of an hourglass-shaped filament constituting a lower concentration of oxygen vacancies due to the fluid oxygen diffusion in the thin oxide. Consequently, the proposed model can explain the electroforming-free device behaviors, including the retention failure mechanism, and suggest an optimized filament configuration for improved retention characteristics. The proposed model can plausibly explain both the electroformed and the electroforming-free devices. Therefore, it can be a standard model for valence change memristors.

Background Although acute hepatitis E is not fatal in healthy individuals, it is unclear whether hepatitis E superinfection increases the mortality in patients with pre-existing liver disease. Thus, we investigated the prognosis of patients with acute hepatitis E according to their cirrhosis diagnosis, and the prognosis according to the development of acute-on-chronic liver failure (ACLF) in patients with cirrhosis and chronic liver disease (CLD). Methods This study included 74 consecutive patients who were diagnosed with acute viral hepatitis E between January 2007 and December 2019. Of them, 39 patients without CLD, 13 patients with non-cirrhotic CLD, and 22 patients with cirrhotic CLD were analyzed. Results Among the 74 patients with HEV infection, 7 (9.5%) died within 180 days: 5 with underlying cirrhosis (71.4%) and 2 without cirrhosis (28.6%). The 180-day mortality was significant higher for patients with cirrhosis than for patients without cirrhosis (22.7% vs. 3.8%, P = 0.013). The age- and sex-adjusted proportional-hazard model revealed an approximately eightfold increase in the 180-day mortality risk in patients with cirrhosis compared to patients without cirrhosis. In addition, development of hepatitis E virus-related ACLF due to acute liver function deterioration in patients with pre-existing CLD or cirrhosis worsened the 180-day mortality rate. Conclusions Our findings suggest that the acute hepatitis E mortality rate was low in healthy individuals but higher in patients with cirrhosis, and especially high in those with ACLF.

Descriptors indicating activity and stability of G-SACs and a guideline for material design are suggested through pre hoc analysis.

International audience; Background: Although smoking is classified as a risk factor for severe COVID-19 outcomes, there is a scarcity of studies on prevalence of smoking during the COVID-19 pandemic. Thus, this study aims to analyze the trends of prevalence of smoking in adolescents over the COVID-19 pandemic period. Methods: The present study used data from middle to high school adolescents between 2005 and 2021 who participated in the Korea Youth Risk Behavior Web-based Survey (KYRBS). We evaluated the smoking prevalence (ever or daily) by year groups and estimated the slope in smoking prevalence before and during the pandemic. Results: A total of 1,137,823 adolescents participated in the study [mean age, 15.04 years [95% confidence interval (CI) 15.03–15.06]; and male, 52.4% (95% CI 51.7–53.1)]. The prevalence of ever smokers was 27.7% (95% CI 27.3–28.1) between 2005 and 2008 but decreased to 9.8% (95% CI 9.3–10.3) in 2021. A consistent trend was found in daily smokers, as the estimates decreased from 5.4% (95% CI 5.2–5.6) between 2005 and 2008 to 2.3% (95% CI 2.1–2.5) in 2021. However, the downward slope in the overall prevalence of ever smokers and daily smokers became less pronounced in the COVID-19 pandemic period than in the pre-pandemic period. In the subgroup with substance use, the decreasing slope in daily smokers was significantly more pronounced during the pandemic than during the pre-pandemic period. Conclusions: The proportion of ever smokers and daily smokers showed a less pronounced decreasing trend during the pandemic. The findings of our study provide an overall understanding of the pandemic’s impact on smoking prevalence in adolescents. [MediaObject not available: see fulltext.]

An effective pathway to build macroscopic scale functional architectures bearing diverse structural dimensions is one of the critical challenges in the two-dimensional (2D) MXene research area. Unfortunately, assembling MXene without adhesive binder is largely limited due to its innate brittle nature and the relatively weak inter-flake van der Waals contact, in contrast to other mechanically compliant 2D materials such as graphene. Herein, an electrochemical self-assembly of pure Ti3C2Tx MXenes is presented for functional multidimensional MXene structures, effectively driven by layer-by-layer spontaneous interfacial reduction at metal template surfaces and subsequent defunctionalization. A three-dimensional open porous aerogel as well as 2D highly stacked thin film structures could be readily obtained in this approach, along with largely enhanced electrical properties induced by spontaneous removal of charge-trapping oxygen functional groups. Accordingly, supercapacitors and electromagnetic interference shielding films based on the multidimensional assembly demonstrate excellent performances.

Hybridization of low-dimensional components with diverse geometrical dimensions should offer an opportunity for the discovery of synergistic nanocomposite structures. In this regard, how to establish a reliable interfacial interaction is the key requirement for the successful integration of geometrically different components. Here, we present 1D/2D heterodimensional hybrids via dopant induced hybridization of 2D Ti3C2Tx MXene with 1D nitrogen-doped graphene nanoribbon. Edge abundant nanoribbon structures allow a high level nitrogen doping (∼6.8 at%), desirable for the strong coordination interaction with Ti3C2Tx MXene surface. For piezoresistive pressure sensor application, strong adhesion between the conductive layers and at the conductive layer/elastomer interface significantly diminishes the sensing hysteresis down to 1.33% and enhances the sensing stability up to 10 000 cycles at high pressure (100 kPa). Moreover, large-area pressure sensor array reveals a high potential for smart seat cushion-based posture monitoring application with high accuracy (>95%) by exploiting machine learning algorithm.

We use CeO

Two-dimensional (2D) MXene has shown enormous potential in scientific fields, including energy storage and electromagnetic interference (EMI) shielding. Unfortunately, MXene-based material structures generally suffer from mechanical fragility and vulnerability to oxidation. Herein, mussel-inspired dopamine successfully addresses those weaknesses by improving interflake interaction and ordering in MXene assembled films. Dopamine undergoes in situ polymerization and binding at MXene flake surfaces by spontaneous interfacial charge transfer, yielding an ultrathin adhesive layer. Resultant nanocomposites with highly aligned tight layer structures achieve approximately seven times enhanced tensile strength with a simultaneous increase of elongation. Ambient stability of MXene films is also greatly improved by the effective screening of oxygen and moisture. Interestingly, angstrom thick polydopamine further promotes the innate high electrical conductivity and excellent EMI shielding properties of MXene films. This synergistic concurrent enhancement of physical properties proposes MXene/polydopamine hybrids as a general platform for MXene based reliable applications.

Two-dimensional (2D) materials are promising components for defect passivation of metal halide perovskites. Unfortunately, commonly used polydisperse liquid-exfoliated 2D materials generally suffer from heterogeneous structures and properties while incorporated into perovskite films. We introduce monodisperse multifunctional 2D crystalline carbon nitride, poly(triazine imide) (PTI), as an effective defect passivation agent in perovskite films via typical solution processing. Incorporation of PTI into perovskite film can be readily attained by simple solution mixing of PTI dispersions with perovskite precursor solutions, resulting in the highly selective distribution of PTI localized at the defective crystal grain boundaries and layer interfaces in the functional perovskite layer. Several chemical, optical, and electronic characterizations, in conjunction with density functional theory calculations, reveal multiple beneficial roles from PTI: passivation of undercoordinated organic cations at the surface of perovskite crystal, suppression of ion migration by blocking diffusion channels, and prevention of hole quenching at perovskite/SnO

A rowhammer error represents a loss of data stored in a DRAM cell caused by electromagnetic interference due to repetitive access to the same and/or adjacent rows. Due to the concentrated occurrence of rowhammer errors in specific rows and columns, these errors cannot be corrected by the conventional error correcting code (ECC) commonly used in DRAM devices. Previous techniques avoid these errors by having additional refresh operations that require additional hardware resources and/or power consumption. This paper proposes a different approach to handle rowhammer errors by distributing them across different DRAM rows and columns so that the attack cells are not concentrated on specific rows and columns. To this end, the distribution of rowhammer errors is observed with experiments using several commercial DRAM devices by employing state-of-the-art rowhammer attack techniques. The observation of the rowhammer errors concentrated in specific rows and columns underlies the proposal of an effective DRAM address remapping scheme for re-distribution of rowhammer errors. By using different address mappings to different chips and arrays in a DIMM, the proposed remapping effectively distributes errors over different rows and columns. As a result, the proposed remapping scheme decreases the possibility of multiple errors in a single word, and consequently, reduces uncorrectable errors under single error or single symbol correcting ECC. Experimental results with commercial DIMMs show that the proposed scheme reduces uncorrectable errors by about 95 percent while incurring a small additional hardware cost.

(연구배경 및 목적) 본 연구는 서대문 독립공원 내에 전국에 흩어져 있거나 별도의 추념공간이 없는 독립지사를 한곳에서 차이 없이 추모하는 공간을 마련하고 이와 연계하여 전시공간과 교육 홍보 공간의 건립여부를 가늠해보기 위한 기본계획 수립 및 추진과정에 대한 검토를 목적으로 하였다. (연구방법) 이를 위해 추모공간의 건축 및 조형물의 기본계획을 위한 시설의 필요성과 입지의 타당성을 논증하고 기본 설계안을 제시하였다. 또한 문화사적지인 해당부지의 제반 법규와 이에 따른 절차를 정리하여 이에 대한 문화재 현상변경 심의의 결과까지를 기술하였고 이를 통해 추후 계획에 필요한 전략을 제언하였다. (결과) 추모공간의 증축을 제안하는 제1안의 해당부지는 기존의 독립관 자리로서 전시실과 함께 위패 20,000위의 봉안에 필요한 공간면적을 추산하여 계획하는 한편, 2019년에 확정된 서대문형무소 종합정비계획 내 승인되어 있는 추모비 재설치 1식을 근거로 현재 설치된 추모 조형비에 공간적 개념을 대입한 대 국민 공모전의 대상작 조형물을 설치하는 제2안으로 기본계획을 제안하였다. 서대문 독립공원 전체 권역은 건축을 비롯한 설치 행위를 하기 위해‘문화재현상변경허가’와‘공원조성계획 변경결정’을 득하여 야만 한다. 특히 증축을 방법으로 하고 있는 제1안은 이 두가지 법제에 대한 검토가 선행되어야 하는데, 그중 건축 기본계획에 대한 문화재 현상변경허가는 2018년 문화재위원회에서의 심의결과“서대문형무소 종합정비계획 확정과 연계, 신축 적정성 여부 등에 대하여 재검토할 필요가 있다고 판단되어 심의가 보류”되었다. 또한 조형물을 설치하는 제2안의 기본계획의 내용 역시 2019년 문화재위원회 심의결과“설치하고자 하는 추모공간이 해당사적지의 보존과 관리에 비치는 영향이 크고 적정성이 부족한 것으로 판단되어 심의가 부결”되었다. (결론) 제1안의 경우, 추모시설의 필요성과 장소의 당위성은 충족되고 있으며, 심의이후 확정된 서대문형무소 종합정비계획에서 정비구역의 경계가 해당 부지와 중복되지 않고 복원 프로그램이 상충하지 않으므로 원안의 변경 없이 재심의 접수하여 재추진 할 수 있다. 그러나 제2안의 경우, 이미 서대문형무소 종합정비계획 내 승인되어 있는 추모비 재설치 1식을 근거로 하고 있음에도‘부결’로서 추진이 불가하게 되었다. 본 연구에서의 기본계획의 내용이 문화재청의 보존 방침에 의해 번번히 좌절되어온 결과는 규제의 역설로 평가될 수 있다. 문화재청의 입장인‘ 온전한 장소 그 자체’로 후세들에게 전달되기 위해서는 증가일로의 관람객에 대응하는 추모와 전시기능의 개선을 위한 장기플랜의 마련이 시급하다. 이를 위하여 무엇보다 문화재 심의위원회의 추모공간의 필요성 및 현황에 대한 인식의 변화가 절실히 요구되는 시점이다.

Text-based retrieval systems have been popular, but content-based retrieval systems have gained widespread acceptance in recent years to directly retrieve diverse media based on their visual content, such as color, texture, and shape. Among many content-based retrieval systems, sketch-based media retrieval systems have attracted attention recently with the proliferation of tablet PCs and smart mobile devices. Sketch-based retrieval requires the user to draw a freehand sketch query, but freehand drawing can be challenging for those with limited drawing skills. This degrades retrieval performance, since successful retrieval depends on the quality of the sketch query image drawn by the user. To address this issue, we propose a real-time stroke guidance for freehand sketch retrieval that continuously displays next-stroke shadow sketches on the canvas based on the user's step-by-step partial strokes. We train a stroke guidance network that learns the mapping between the step-wise stroke relations to predict the user's next stroke. The proposed stroke guidance for freehand sketch retrieval system runs on a five step next-stroke prediction model that identifies candidate next-stroke sketches from a database of millions of sketches. The system retrieves variable number of sketch object classes at different drawing stages. During the initial sketching stage, diverse drawing possibilities are covered by retrieving multiple sketch classes; as the sketching progresses, the intended sketch class is narrowed down to one. Deep binary hashing is employed for efficient similarity matching of relevant next-stroke sketches. We extend the Google QuickDraw dataset to create a five step sketch stroke database. Qualitative and quantitative experiments are conducted to verify the effectiveness of the proposed system, which can be utilized for drawing guidance, tracing, and sketch retrieval. Tracing refers to the act of copying the shadowed line of a guiding image by drawing over its lines.

The alkaline environment in anion-exchange membrane fuel cells allows the use of Pt-free electrocatalysts, thus reducing the system cost. We performed a theoretical high-throughput study of various low-cost Ag-based oxygen reduction reaction anode electrocatalysts and assessed their catalytic performance using density functional theory. From the Materials Project database, a total of 106 binary Ag alloys were investigated by estimating their heat of formation, dissolution potential, and overpotential on low-index surfaces. We confirmed that EuAg₅, BaAg₅, and SrAg₅ have higher catalytic activities and durabilities than pure Ag. By following the chemical trend of the results, we further proposed LaAg₅ and PrAg₅, which were not included in the database, as promising candidates. All candidates are in the space group P6/mmm and contain alkaline earth metal or lanthanide elements.

An effective pathway to build macroscopic scale functional architectures bearing diverse structural dimensions is one of the critical challenges in the two-dimensional (2D) MXene research area. Unfortunately, assembling MXene without adhesive binder is largely limited due to its innate brittle nature and the relatively weak inter-flake van der Waals contact, in contrast to other mechanically compliant 2D materials such as graphene. Herein, an electrochemical self-assembly of pure Ti

Hybridization of low-dimensional components with diverse geometrical dimensions should offer an opportunity for the discovery of synergistic nanocomposite structures. In this regard, how to establish a reliable interfacial interaction is the key requirement for the successful integration of geometrically different components. Here, we present 1D/2D heterodimensional hybrids via dopant induced hybridization of 2D Ti

Background Acute-on-chronic liver failure (ACLF) is a widely recognized concept in which acute decompensation (AD) in patients with cirrhosis results in organ failures and high short-term mortality. However, few studies reflecting the various etiologies of cirrhosis are available. We aimed to investigate the clinical features of patients with hepatitis C virus (HCV)-related ACLF. Methods Between January 2005 and December 2018, 109 HCV-related cirrhosis patients who were hospitalized for AD (ascites, hepatic encephalopathy, gastrointestinal hemorrhage, and/or bacterial infection) were enrolled for ACLF defined by European Association for the Study of the Liver (EASL). Results ACLF developed in 35 patients (32.1%) on admission. Eight patients had ACLF grade 1, eight had ACLF grade 2, and 19 had ACLF grade 3. The 28-day and 90-day mortality rates were very low (2.7% and 5.4%, respectively) in patients without ACLF and very high (60.0% and 74.3%, respectively) in those with ACLF. In patients with HCV-related ACLF, the prevalence of liver failure was very low (17.1%), whereas that of kidney failure was very high (71.4%) compared to previous studies on hepatitis B virus-related ACLF and alcohol-related ACLF. Compared with all other prognostic scores, Chronic liver failure Consortium Organ Failure score most accurately predicted 90-day mortality, with an area under the receiver operator characteristic of 0.921. Conclusions HCV-related ACLF has unique clinical characteristics that are distinct from hepatitis B virus-related and alcohol-related ACLF. ACLF defined by EASL can be useful in predicting short-term mortality in HCV-related cirrhosis.

Two-dimensional (2D) MXene has shown enormous potential in scientific fields, including energy storage and electromagnetic interference (EMI) shielding. Unfortunately, MXene-based material structures generally suffer from mechanical fragility and vulnerability to oxidation. Herein, mussel-inspired dopamine successfully addresses those weaknesses by improving interflake interaction and ordering in MXene assembled films. Dopamine undergoes

Engineering faces many wicked problems: irreducibly interdisciplinary with multiple competing objectives, and of such large scale and complexity that will require processes to deeply rely on human insights and power of computation. The resurgence of machine learning offers the possibility for new forms of human/computer collaboration where each fuels hybrid intelligence in complementary ways. A concept of virtual design assistant (VDA) is developed as a platform to bring the hybrid intelligence in solving complex design challenges. A deep learning-based abstraction process is developed to provide VDA a function to extract structured functional requirements from fragmental design specifications and customer needs.

This paper proposes a GPU-based Near-data-processing (NDP) architecture as well as a well-matched programming model considering both the characteristics of image applications and NDP constraints. First, data allocation to the processing unit is handled to keep the data locality considering the memory access pattern. Second, this predictable allocation enables to design a compact but efficient NDP architecture. By applying a prefetcher that leverages the pattern aware data allocation, the number of active warps and on-chip SRAM size of NDP are significantly reduced. This allows to satisfy the NDP constraints and increases the opportunity to integrate more processing units on a memory logic die. The evaluation results for various image processing benchmarks show that the proposed NDP GPU improves the performance compared to the baseline GPU.

Recently, dramatic improvements in memory performance have been highly required for data demanding application services such as deep learning, big data, and immersive videos. To this end, the throughput-oriented memory such as high bandwidth memory (HBM) and hybrid memory cube (HMC) has been introduced to provide a high bandwidth. For its effective use, various research efforts have been conducted. Among them, the near-memory-processing (NMP) is a concept that utilizes bandwidth and power consumption by placing computation logic near the memory. In the NMP-enabled system, a processor hierarchy consisting of hosts and NMPs is formed based on the distance from the main memory. In this paper, an evaluation tool is proposed to obtain the optimal design decision considering the power-time trade-off in the processor hierarchy. Every time the operating condition and constraints change, the decision of task-level offloading is dynamically made. For the realistic NMP-enabled system environment, the relationship among HBM, host, and NMP should be carefully considered. Hosts and NMPs are almost hidden from each other and the communications between them are extremely limited. In the simulation results, popular benchmarks and a machine learning application are used to demonstrate power-time trade-offs depending on applications and system conditions.

Data Distribution Service (DDS) is a standard communication middleware that is suitable for real-time distributed communication with enhanced flexibility, scalability and interoperability. DDS discovery is a procedure to search the participants and endpoints of DDS network. DDS relies on a multicast mechanism in discovering DDS participants. Due to the features of multicast, DDS has limited discovery range and excessive network traffic. It also wastes of memory space of DDS nodes to keep information of discovered but not communicating participants. Topic Naming Service (TNS) is proposed in this paper in order to solve these problems. TNS maintains a Topic Name Space for managing relationships between endpoints. It selectively delivers discovery messages to appropriate local networks according to the relationship, instead of multicasting the message into the whole network. Through these mechanisms, TNS solves the range limitation of discovery and inefficient resource usage of DDS.

Teaching consultation has a lot of advantage in enhancing the quality of lectures but is hardly ever well implemented by the lecturers. This paper has discovered solutions to few factors which kept lecturers from complying. Online teaching consultation can offer lecturers more meaningful inputs, and the clinic experts a way of providing feedbacks efficiently.

As the need for education with a weight on learning outcome grew, also did the accurate measurement of it. Evidence of learning outcome through varies activities such as homework, assignments, test results and etc. should continuously be gathered. The following research proposes an online evaluation system leading to enhancement in learning outcome, overall score and learning

목적: 운동부하 심전도 검사(XECG)와 관상동맥 컴퓨터단층 촬영술(CTCA)은 현재 임상에서 관상동맥 질환의 초기 진단법으로 널리 사용하고 있다. 본 연구는 CTCA와 XECG를 동시에 시행한 환자에서 각 검사의 결과에 따른 고식적 관상동맥 조영술(CCA) 및 재관류시술(RT)의 시행률을 관찰하였고 CCA가 진행된 환자에서 각 검사의 진단능을 비교 분석하여 선별 검사에서 각 검사의 역할과 제한점을 비교하고자 하였다. 방법: 2006년 1월부터 20010년 3월까지 경상대학교병원 외래에서 관상동맥 질환을 평가하기 위해 CTCA와 XECG 검사를 같이 시행한 환자 598명의 임상자료들을 후향적으로 분석하였다. 결과: 전체 589명 중 107명(19%)에서 보다 정확한 검사 및 RT를 위해 CCA가 진행되었으며 77명(12.8%) 환자에서 한 가지 이상의 혈관에서 의미 있는 협착(≥ 50%)이 발견되었고, 65명(11%)의 환자에서 RT이 시행되었다. CTCA에서 의미 있는 협착(≥ 50%)을 보인 120명에서는 RT/CCA가 58(48%)/75 (62%)명에서 시행되었지만, XECG에서 양성을 보인 115명 중 RT/CCA 23 (20%)/41 (35%)명에서 시행되었다(p