The generalized Fermat type difference equations

Kai Liu,Lei Ma,Xiaoyang Zhai 대한수학회 2018 대한수학회보 Vol.55 No.6

This paper is to consider the generalized Fermat difference equations with different types which ever considered by Li \cite{li}, Ishizaki and Korhonen \cite{IK}, Zhang \cite{zhangjie} and Liu \cite{liuk4,11,1177,liu}, respectively. Some new observations and results on these equations will be given.

A Dual Functional Ti-Ga Alloy: Inhibiting Biofilm Formation and Osteoclastogenesis Differentiation via Disturbing Iron Metabolism

Fupeng Li,Kai Huang,Jinbing Wang,Kai Yuan,Yiqi Yang,Yihao Liu,Xianhao Zhou,Keyu Kong,Tao Yang,Jian He,Chunjie Liu,Haiyong Ao,Fengxiang Liu,Qian Liu,Tingting Tang,Shengbing Yang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Although biomedical implants have been widely used in orthopedic treatments, two major clinical challenges remain to be solved, one is the bacterial infection resulting in biofilm formation, and the other is aseptic loosening during implantation due to over-activated osteoclastogenesis. These factors can cause many clinical issues and even lead to implant failure. Thus, it is necessary to endow implants with antibiofilm and aseptic looseningprevention properties, to facilitate the integration between implants and bone tissues for successful implantation. To achieve this goal, this study aimed to develop a biocompatible titanium alloy with antibiofilm and anti-aseptic loosening dual function by utilizing gallium (Ga) as a component. Methods A series of Ti-Ga alloys were prepared. We examined the Ga content, Ga distribution, hardness, tensile strength, biocompatibility, and anti-biofilm performance in vitro and in vivo. We also explored how Ga3+ ions inhibited the biofilm formation of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and osteoclast differentiation. Results The alloy exhibited outstanding antibiofilm properties against both S. aureus and E. coli in vitro and decent antibiofilm performance against S. aureus in vivo. The proteomics results demonstrated that Ga3+ ions could disturb the bacterial Fe metabolism of both S. aureus and E. coli, inhibiting bacterial biofilm formation. In addition, Ti-Ga alloys could inhibit receptor activator of nuclear factor-κB ligand (RANKL)-dependent osteoclast differentiation and function by targeting iron metabolism, then suppressing the activation of the NF-κB signaling pathway, thus, showing their potential to prevent aseptic loosening. Conclusion This study provides an advanced Ti-Ga alloy that can be used as a promising orthopedic implant raw material for various clinical scenarios. This work also revealed that iron metabolism is the common target of Ga3+ ions to inhibit biofilm formation and osteoclast differentiation.

The Clinical Observation of Inflammation Theory for Depression: The Initiative of the Formosa Long COVID Multicenter Study (FOCuS)

Shu-Tsen Liu(Shu-Tsen Liu),Sheng-Che Lin(Sheng-Che Lin),Jane Pei-Chen Chang(Jane Pei-Chen Chang),Kai-Jie Yang(Kai-Jie Yang),Che-Sheng Chu(Che-Sheng Chu),Chia-Chun Yang(Chia-Chun Yang),Chih-Sung Liang( 대한정신약물학회 2023 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.21 No.1

There is growing evidence that the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with increased risks of psychiatric sequelae. Depression, anxiety, cognitive impairments, sleep disturbance, and fatigue during and after the acute phase of COVID-19 are prevalent, long-lasting, and exerting negative consequences on well-being and imposing a huge burden on healthcare systems and society. This current review presented timely updates of clinical research findings, particularly focusing on the pathogenetic mechanisms underlying the neuropsychiatric sequelae, and identified potential key targets for developing effective treatment strategies for long COVID. In addition, we introduced the Formosa Long COVID Multicenter Study (FOCuS), which aims to apply the inflammation theory to the pathogenesis and the psychosocial and nutrition treatments of post-COVID depression and anxiety.

Coding-Assisted Broadcast Scheduling via Memetic Computing in SDN-Based Vehicular Networks

Liu, Kai,Feng, Liang,Dai, Penglin,Lee, Victor C. S.,Son, Sang Hyuk,Cao, Jiannong IEEE 2018 IEEE transactions on intelligent transportation sy Vol.19 No.8

<P>This paper embarks the first study on exploiting the synergy between vehicular caching and network coding for enhancing the bandwidth efficiency of data broadcasting in heterogeneous vehicular networks by presenting a service architecture that exercises the software defined network concept. In particular, we consider the scenario where vehicles request a set of information and they could be served via heterogeneous wireless interfaces, such as roadside units and base stations (BSs). We formulate a novel problem of coding-assisted broadcast scheduling (CBS), aiming at maximizing the broadcast efficiency for the limited BS bandwidth by exploring the synergistic effect between vehicular caching and network coding. We prove the NP-hardness of the CBS problem by constructing a polynomial-time reduction from the simultaneous matrix completion problem. To efficiently solve the CBS problem, we employ memetic computing, which is a nature inspired computational paradigm for tackling complex problems. Specifically, we propose a memetic algorithm, which consists of a binary vector representation for encoding solutions, a fitness function for solution evaluation, a set of operators for offspring generation, a local search method for solution enhancement, and a repair operator for fixing infeasible solutions. Finally, we build the simulation model and give a comprehensive performance evaluation to demonstrate the superiority of the proposed solution.</P>

Stability Analysis of Discrete-Time Piecewise-Linear Systems: A Generating Function Approach

Kai Liu,Jianghai Hu,Yu Yao,Baoqing Yang,Xin Huo 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.5

This paper studies the exponential stability of a class of discrete-time piecewise-linear systems (DPLS). Some basic properties of the proposed DPLS are established, which enables the generating function approach to be used for the system stability analysis. By introducing the generating functions of DPLS and showing their properties, a sufficient and necessary condition for the exponential stability of DPLS is derived. Furthermore, the maximum exponential growth rate of system trajectories can be obtained exactly by computing the radii of convergence of the generating functions. The algorithm for computing the generating functions is developed and two examples are given to demonstrate the proposed approach.

Reading and Writing Our Own Stories : The Alternative Reading Group

LIU, Kai-ling Asian Center Women's Studies Korean Women's Instit 2002 Asian Journal of Women's Studies(AJWS) Vol.8 No.2

Since women are the primary participants in most reading groups in Taiwan, this research experiments with the use of women's personal narratives in one such group. Reading of ordinary women's personal narratives encourages women to reflect on their own lives and then write out their own life stories. Further, with the sense of community that this reading and writing generates, women may come to a better recognition of their own value. This group, comprising ten middle-aged women, held two-hour meetings once a week for twenty weeks. In the reading phase, the participants read 7 publications of women's personal narratives, which came in various forms such as letters, diaries, autobiographies, oral testimonies, and biographies. In the writing phase, the participants wrote their life stories, dwelling on themes of family, education, women and the body, the family-in-law, care-giving, appearance, and miscellany. This exercise led to three kinds of results. First, the reading of ordinary women's personal narratives introduced participants with the form and content of writing life stories. Then, the writing of their own life stories enabled the women participants to re-evaluate their past. Third, with the reading, writing, and group sharing, a collection of writing or what I call a `community of narratives' was formed. This helped the participants recognize the differences amongst them and at the same time to value their own experience.

Performance Evaluation in Grasp Strength and Slip Resistance of a Robotic hands

Kai Liu(류카이),Usman Cheema(우스만 치마),Hanul Son(손하늘),Dongik Kim(김동익),Seungbin Moon(문승빈) 대한전기학회 2020 정보 및 제어 심포지엄 논문집 Vol.2020 No.10

Orientation-dependent structural and electronic properties of Ge/<i>a</i>-GeO₂ interfaces: first-principles study

Liu, Kai,Ko, Eunjung,Kim, Sangtae,Park, Jaehong,Hwang, Cheol Seong,Choi, Jung-Hae IOP 2019 Journal of Physics. D, Applied Physics Vol.52 No.15

<P>While the properties of the non-(1 0 0) Ge surface become more important with the scaling down of Ge-based transistor devices, the stability and electronic properties of the interface between non-(1 0 0) Ge and amorphous GeO<SUB>2</SUB> (<I>a-</I>GeO<SUB>2</SUB>) compared to those of Ge(1 0 0) and <I>a</I>-GeO<SUB>2</SUB> are still not well known. In this study, first-principles calculations were performed to systematically study the atomic and electronic structures of Ge/<I>a-</I>GeO<SUB>2</SUB> interfaces with various surface orientations of Ge. The study shows that the Ge(1 1 1)/<I>a-</I>GeO<SUB>2</SUB> and Ge(1 0 0)/<I>a-</I>GeO<SUB>2</SUB> interfaces have the lowest and highest interface energies, respectively. The stability of the Ge/<I>a-</I>GeO<SUB>2</SUB> interface is governed by the interfacial bond density and the minimization of the dangling bonds. We find that the interface region, composed of the Ge suboxides, dominates the electronic structures of the Ge/<I>a-</I>GeO<SUB>2</SUB>. The Ge atoms with uncompensated dangling bonds result in various trap states within the band gap of Ge, which is related to the charge neutrality level of the Ge defect. The band offsets between Ge and <I>a</I>-GeO<SUB>2</SUB> show little dependence on the original Ge orientation.</P>

Network-Coding-Assisted Data Dissemination via Cooperative Vehicle-to-Vehicle/-Infrastructure Communications

Liu, Kai,Ng, Joseph Kee-Yin,Wang, Junhua,Lee, Victor C. S.,Wu, Weiwei,Son, Sang Hyuk IEEE 2016 IEEE transactions on intelligent transportation sy Vol.17 No.6

<P>Vehicle-to-vehicle/vehicle-to-infrastructure (referred to as V2X) communications have potential to revolutionize current road transportation systems with respect to vehicle safety, transportation efficiency, and travel experience. This paper puts the first effort on applying network coding in cooperative V2X communication environments to improve bandwidth efficiency and enhance data service performance. Specifically, we investigate new arising challenges on network-coding-assisted data dissemination by considering both communication constraints and application requirements in vehicular networks. We present the system model and give an insight into the characteristics of cooperative data dissemination with network coding. On this basis, we formulate the problem and propose a network-coding-assisted scheduling algorithm to enable the hybrid of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications and exploit their joint effects on providing efficient data services. We design a cache strategy that allows vehicles to retrieve their unrequested data items. This strategy not only increases the opportunity of data sharing among vehicles but also gives higher probability of packet decoding, which in turn enhances the data service performance. We give an intensive analysis on the scheduling overhead, which shows the scalability of the algorithm. Finally, we build the simulation model and conduct a comprehensive performance evaluation to demonstrate the superiority of the proposed solution.</P>

Cooperative Data Scheduling in Hybrid Vehicular Ad Hoc Networks: VANET as a Software Defined Network

Liu, Kai,Ng, Joseph K. Y.,Lee, Victor C.S.,Son, Sang H.,Stojmenovic, Ivan Institute of Electrical and Electronics Engineers, 2016 IEEE/ACM transactions on networking Vol.24 No.3

<P>This paper presents the first study on scheduling for cooperative data dissemination in a hybrid infrastructure-to-vehicle (I2V) and vehicle-to-vehicle (V2V) communication environment. We formulate the novel problem of cooperative data scheduling (CDS). Each vehicle informs the road-side unit (RSU) the list of its current neighboring vehicles and the identifiers of the retrieved and newly requested data. The RSU then selects sender and receiver vehicles and corresponding data for V2V communication, while it simultaneously broadcasts a data item to vehicles that are instructed to tune into the I2V channel. The goal is to maximize the number of vehicles that retrieve their requested data. We prove that CDS is NP-hard by constructing a polynomial-time reduction from the Maximum Weighted Independent Set (MWIS) problem. Scheduling decisions are made by transforming CDS to MWIS and using a greedy method to approximately solve MWIS. We build a simulation model based on realistic traffic and communication characteristics and demonstrate the superiority and scalability of the proposed solution. The proposed model and solution, which are based on the centralized scheduler at the RSU, represent the first known vehicular ad hoc network (VANET) implementation of software defined network (SDN) concept.</P>