Chun-cheng Chen

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Current 802.11 WLANs rely on the 802.11 MAC (medium access control) and careful channel assignment to resolve intraand inter-BSS (basic service set) interferences respectively. However, because wireless transmissions interfere with each other in a range that is larger than the communication range and because there is only a very limited number of orthogonal(More)
The majority of existing wireless rate controls are based on the implicit assumption that frames are corrupted due to the random, arbitrary environmental and thermal noises. They generally reduce the channel rate on frame losses, trading lower efficiency in frequency band utilization for more robust modulation so that the current noise level may be(More)
The limited number of orthogonal channels and the autonomous installations of hotspots and home wireless networks often leave neighboring 802.11 basic service sets (BSS’s) operating on the same or overlapping channels, therefore interfering with each other. However, the 802.11 MAC does not work well in resolving inter-BSS interferences due to the well-known(More)
OBJECTIVE The objective of this study was to investigate the effect of different Er,Cr:YSGG laser parameters on the morphology of irradiated dentine and the shear bond strength between resin composites and irradiated dentine. MATERIALS AND METHODS Dentine specimens prepared from extracted human third molars were randomly assigned to six groups, including(More)
As more and more cities plan to deploy municipal wireless mesh networks to provide publicly-accessible infrastructure, it becomes critical to come up with a deployment plan that provides sufficient accessibility with financial and technological constraints. In this paper, we consider deploying the mesh routers that are equipped with directional antennas to(More)
OBJECTIVES This study was designed to improve the initial biocompatibility of titanium (Ti) using an Er,Cr:YSGG-powered hydrokinetic system. METHODS The Er,Cr:YSGG-powered hydrokinetic system with different laser energy densities, 125 and 190 J/cm(2), were applied to the Ti substrate. Human osteosarcoma U2-OS cells were used. The difference in the(More)
The limited number of orthogonal channels and autonomous installations of hot spots and home wireless networks often leave neighboring 802.11 basic service sets (BSSs) operating on the same or overlapping channels, therefore interfering with each other. However, the 802.11 medium access control (MAC) does not work well in resolving inter-BSS interference(More)
In this paper, we propose Opportunistic Carrier Prediction (OCP) that jointly addresses exposed terminal and hidden terminal problems in wireless networks. OCP is based on the rationale that past interference information can be a good indicator for the outcome of future packet delivery. Therefore, each OCP sender maintains a summary of past interference(More)
OBJECTIVE The study is to evaluate the effect of surface roughness of titanium implants on bacterial adhesion and then to investigate the efficacy of the three cleaning treatments for bacterial removal in titanium surfaces. BACKGROUND DATA Although surface debridement is the basic element for treatment of peri-implantitis to reduce bacterial adhesion,(More)
INTRODUCTION The purpose of this study was to examine the in vitro bioactivity and biocompatibility of sol-gel-derived dicalcium silicate cements. METHODS The morphology, phase composition, and compressive strength of the novel cement were investigated after immersion in a simulated body fluid for different periods of time. Cement biocompatibility was(More)