Privacy-preserving PKI design based on group signature

Nowadays, Internet becomes a part of our life. We can make use of numerous services with personal computer, Lap-top, tablet, smart phone or smart TV. These devices with network make us enjoy ubiquitous computing life. Sometimes, on-line services request us authentication or identification for access control and authorization, and PKI technology is widely used because of its security. However the possibility of privacy invasion will increase, if We’re identified with same certificate in many services and these identification data are accumulated. For privacy-preserving authentication or anonymous authentication, there have been many researches such as Group signatures, anonymous credentials, etc. Among these researches, group signatures are very practical Because they provide unlinkability and traceability as well as anonymity. In this paper, we propose a privacy-preserving PKI based on group signature, with which users’ privacy can be Kept in services. Because of traceability, their identities can be traced if they abuse anonymity such as cybercrime. Moreover, we will also discuss open issues for further studies

Endovascular Treatment of Arterial Steno-Occlusive Lesions in Symptomatic Moyamoya Disease

The efficacy and safety of endovascular treatment (EVT) for moyamoya disease (MMD) have rarely been investigated. The objective of this study was to summarize the clinical outcomes of EVT for MMD and determine the potential role of EVT in treating symptomatic steno-occlusive lesions in MMD. Reports from January 2000 to December 2021 describing EVT in MMD were collected through a literature search. The search terms included “moyamoya”, “stent”, “angioplasty”, and “endovascular”. Data regarding baseline demographics, previous medical history, treated vessel, periprocedural complications, and angiographical recurrence were retrieved. This review included 10 studies with details of 19 patients undergoing a total of 31 EVT procedures. Twenty-one EVTs were performed as initial treatments for MMD, and 10 were performed as additional treatments for angiographical recurrence. The mean follow-up period of the initial EVTs was 9.0±11.9 months, with angiographical recurrence in 11 (68.8%) cases. The mean follow-up period of additional EVTs was 4.3±3.9 months, and seven (70.0%) EVTs showed restenosis of the re-treated vessel. Across all initial and additional EVTs, there were no differences in characteristics between the recurrence and non-recurrence groups. Overall, two periprocedural complications (9.5%) occurred, one vessel rupture and one massive intracerebral hemorrhage with subarachnoid hemorrhage. EVT plays a limited role in the management of symptomatic intracranial arterial steno-occlusive lesions of MMD. Recent advances in understanding the pathomechanism of MMD may urge neuro-interventionists to find a new endovascular approach with better balloon angioplasty or stenting mechanisms

A Solution-Processed Cathode Interfacial Layer Facilitates Efficient Energy Level Alignment in Organic Photovoltaics

We synthesized and used small-molecule cathode interfacial materials in organic photovoltaic devices (OPVs). Two small-molecule interfacial materials with phosphine oxide and benzoimidazole groups induced strong interface dipoles and chelated with the metal electrodes. The molecules can be dissolved in various organic solvents for processing. We used isopropanol (an environmentally benign solvent) to dissolve the small-molecule materials and spin-coated solutions onto photoactive layers. The materials formed ohmic contacts between the electron acceptor PC71 BM and the AI cathodes and facilitated efficient charge carrier extraction at the electrodes of OPVs. Analyses of the material and device properties of the two interfacial materials and the photovoltaic performances of OPVs with the materials revealed that the materials were promising cathode interfacial materials for photovoltaic applications. The interfacial material featuring two benzoimidazole groups optimally formed smooth interfacial layers affording better energy level alignment between the electron acceptors and the cathode.11Nsciescopu

AI-Enhanced design of excavator engine room cooling system using computational fluid dynamics and artificial neural networks

Excavators mainly perform high-load operations in fixed positions, so the stability of their performance depends solely on their cooling system. In this study, computational fluid dynamics (CFD) analysis was conducted using Fluent 2022 R22 software to analyze the cooling system in the engine room of an excavator. A comprehensive parametric study was performed, considering different cooling fan layouts and operating rates, to establish a database of cooling performance data for the excavator. Artificial neural network (ANN) models were trained on the constructed database and were then applied to design the cooling system and predict the performance. Further, optimal designs that maximized the cooling performance and energy efficiency were selected. This study demonstrates the feasibility of using ANN models to quickly and accurately predict and design the cooling system of an excavator in a cost-effective manner

Elucidation of the Formation Mechanism of Highly Oriented Multiphase Ruddlesden-Popper Perovskite Solar Cells

The crystallographic orientation and phase distribution of two-dimensional Ruddlesden-Popper perovskites (2D-RPPs) should be carefully controlled to obtain high-performance 2D-RPP-based opto-electronic devices. However, these characteristics are still unclear. Herein, we systematically examine the formation mechanism of highly oriented multiphase 2D-RPPs. We argue that the 3D-like perovskites containing small organic cations nucleate first with out-of-plane (111) preferential orientation, followed by the further growth of two- dimensional perovskites incorporating bulky organic cations owing to the difference in the solubility between small and bulky cations. This spatial segregation of organic cations across the film depth induces the formation of multiple perovskite phases, which produces n-value-graded 2D-RPP films with continually upshifted band energy alignment. Highly oriented multiphase 2D-RPP films with isobutylammonium (isoBA(2)(Cs(0.02)MA(0.64)FA(0.34))(4)Pb5I6) were successfully employed as a photoabsorbers for perovskite solar cells (PSCs), exhibiting remarkable efficiency of over 16% and significantly enhanced environmental stability compared with their three-dimensional counterparts.11Nsciescopu

Local conductance mapping of water-intercalated graphene on mica

We report that the conductance of graphene is influenced by intercalated water layers using current sensing atomic force microscopy (AFM). We obtained a confined water layer between chemical vapor deposition graphene and mica by transferring graphene onto mica in a liquid water bath. Atomic force microscopy topographic images confirm high coverage by a single water layer, and scanning tunneling microscopy (STM) verifies a clean surface without contamination by measuring the honeycomb lattice structure of the graphene. We show that the surface conductance is perturbed by the presence of a water layer between the graphene and mica, which is not found in the STM topographic image. We found that the graphene on the edge and at pinholes of the water layer exhibits lower conductance, compared with that of graphene on the water terrace. We attribute the perturbation of conductance to structural defects from the water film and a variation of interaction between the edge of the water and graphene. © 2016 Author(s)2