Capacity Improvement with Dynamic Channel Assignment and Reuse Partitioning in Cellular Systems

Chen Steven Li,Chong Peter Han Joo The Korea Institute of Information and Commucation 2006 Journal of communications and networks Vol.8 No.1

In cellular mobile communications, how to achieve optimum system capacity with limited frequency spectrum is one of the main research issues. Many dynamic channel assignment (DCA) schemes have been proposed and studied to allocate the channels more efficiently, thus, the capacity of cellular systems is improved. Reuse partitioning (RP) is another technique to achieve higher capacity by reducing the overall reuse distance. In this paper, we present a network-based DCA scheme with the implementation of RP technique, namely dynamic reuse partitioning with interference information (DRP-WI). The scheme aims to minimize the effect of assigned channels on the availability of channels for use in the interfering cells and to reduce their overall reuse distances. The performance of DRP-WI is measured in terms of blocking probability and system capacity. Simulation results have confirmed the effectiveness of DRP-WI scheme. Under both uniform and non-uniform traffic distributions, DRP-WI exhibits outstanding performance in improving the system capacity. It can provide about 100% capacity improvement as compared to conventional fixed channel assignment scheme with 70 system channels.

CITY BRANDING THROUGH CINEMA: CREATING HONG KONG’S POSTCOLONIAL IDENTITY

Steven Chen,Eric Chuan-Fong Shih 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

City branding is a strategic instrument to publicize a city’s competitive advantages by highlighting distinctive characteristics of the city. This study uses cinema as a discursive lens to examine city branding and explicates a framework for implementing city branding through cinema. An analysis of 81 Hong Kong films produced between 2008 and 2015 reveal the modalities by which city officials and media producers affect a city brand that distinguishes Hong Kong from other East Asian cities. Specifically, Hong Kong filmmakers 1) use local color as backdrops for stories, 2) emphasize freedom of expression, 3) highlight regional localities, and 4) claim historical figures associated with the city. The findings reflect strategic attempts by Hong Kong city officials and media producers to negotiate the city’s postcolonial identity, even two decades after Hong Kong’s reunification with China. The results suggest that Hong Kong uses cinemamediated city branding as a form of subversive resistance to China. More broadly, the implementation framework could be deployed by other emergent cities (e.g. Dubai), which are looking to increase their profile and cultural footprint in the global stage through creative markets.

Terra-Scope - a MEMS-based vertical seismic array

Steven D. Glaser,Min Chen,Thomas E. Oberheim 국제구조공학회 2006 Smart Structures and Systems, An International Jou Vol.2 No.2

The Terra-Scope system is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. They are expected to cost approximately $6000 each. An internal 16-bit, extremely low power MCU controls all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage. Each Pod measures 3-D acceleration, tilt, azimuth, temperature, and other parametric variables such as pore water pressure and pH. Each Pod communicates over a standard digital bus (RS-485) through a completely web-based GUI interface, and has a power consumption of less than 400 mW. Three-dimensional acceleration is measured by pure digital force-balance MEMS-based accelerometers. These accelerometers have a dynamic range of more than 115 dB and a frequency response from DC to 1000 Hz with a noise floor of less than 30 ngrms/Hz. Accelerations above 0.2 g are measured by a second set of MEMS- based accelerometers, giving a full 160 dB dynamic range. This paper describes the system design and the cooperative shared-time scheduler implemented for this project. Restraints accounted for include multiple data streams, integration of multiple free agents, interaction with the asynchronous world, and hardened time stamping of accelerometer data. The prototype of the device is currently undergoing evaluation. The first array will be installed in the spring of 2006.

Contact Angle and Adhesion Dynamics and Hysteresis on Molecularly Smooth Chemically Homogeneous Surfaces

Chen, Szu-Ying,Kaufman, Yair,Schrader, Alex M.,Seo, Dongjin,Lee, Dong Woog,Page, Steven H.,Koenig, Peter H.,Isaacs, Sandra,Gizaw, Yonas,Israelachvili, Jacob N. American Chemical Society 2017 Langmuir Vol.33 No.38

<P>Measuring truly equilibrium adhesion energies or contact angles to obtain the thermodynamic values is experimentally difficult because it requires loading/unloading or advancing/receding boundaries to be measured at rates that can be slower than 1 nm/s. We have measured advancing-receding contact angles and loading-unloading adhesion energies for various systems and geometries involving molecularly smooth and chemically homogeneous surfaces moving at different but steady velocities in both directions, ±<I>V</I>, focusing on the thermodynamic limit of ±<I>V</I> → 0. We have used the Bell Theory (1978) to derive expressions for the dynamic (velocity-dependent) adhesion energies and contact angles suitable for both (i) dynamic adhesion measurements using the classic Johnson-Kendall-Roberts (JKR, 1971) theory of “contact mechanics” and (ii) dynamic contact angle hysteresis measurements of both rolling droplets and syringe-controlled (sessile) droplets on various surfaces. We present our results for systems that exhibited both steady and varying velocities from <I>V</I> ≈ 10 mm/s to 1 nm/s, where in all cases but one, the advancing (<I>V</I> > 0) and receding (<I>V</I> < 0) adhesion energies and/or contact angles converged toward the same theoretical (thermodynamic) values as <I>V</I> → 0. Our equations for the dynamic contact angles are similar to the classic equations of Blake & Haynes (1969) and fitted the experimental adhesion data equally well over the range of velocities studied, although with somewhat different fitting parameters for the characteristic molecular <I>length/dimension</I> or <I>area</I> and characteristic bond formation/rupture <I>lifetime</I> or <I>velocity</I>. Our theoretical and experimental methods and results unify previous kinetic theories of adhesion and contact angle hysteresis and offer new experimental methods for testing kinetic models in the thermodynamic, <I>quasi-static</I>, limit. Our analyses are limited to kinetic effects only, and we conclude that hydrodynamic, i.e., viscous, and inertial effects do not play a role at the interfacial velocities of our experiments, i.e., <I>V</I> < (1-10) mm/s (for water and hexadecane, but for viscous polymers it may be different), consistent with previously reported studies.</P> [FIG OMISSION]</BR>

Quantum critical nature of the short-range magnetic order in Sr2−xLaxIrO4

Rodan, Steven T.,Yoon, Sungwon,Lee, Suheon,Choi, Kwang-Yong,Kim, Gareoung,Rhyee, Jong-Soo,Koda, Akihiro,Chen, Wei-Tin,Chou, Fangcheng American Physical Society 2018 Physical review. B Vol.98 No.21

Terra-Scope - a MEMS-based vertical seismic array

Glaser, Steven D.,Chen, Min,Oberheim, Thomas E. Techno-Press 2006 Smart Structures and Systems, An International Jou Vol.2 No.2

The Terra-Scope system is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. They are expected to cost approximately $6000 each. An internal 16-bit, extremely low power MCU controls all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage. Each Pod measures 3-D acceleration, tilt, azimuth, temperature, and other parametric variables such as pore water pressure and pH. Each Pod communicates over a standard digital bus (RS-485) through a completely web-based GUI interface, and has a power consumption of less than 400 mW. Three-dimensional acceleration is measured by pure digital force-balance MEMS-based accelerometers. These accelerometers have a dynamic range of more than 115 dB and a frequency response from DC to 1000 Hz with a noise floor of less than $30ng_{rms}/{\surd}Hz$. Accelerations above 0.2 g are measured by a second set of MEMS-based accelerometers, giving a full 160 dB dynamic range. This paper describes the system design and the cooperative shared-time scheduler implemented for this project. Restraints accounted for include multiple data streams, integration of multiple free agents, interaction with the asynchronous world, and hardened time stamping of accelerometer data. The prototype of the device is currently undergoing evaluation. The first array will be installed in the spring of 2006.

Comparative effectiveness of bevacizumab plus cisplatin-based chemotherapy versus pemetrexed plus cisplatin treatment in East Asian non-squamous non-small cell lung cancer patients applying real-life outcomes.

Chang, Gee-Chen,Ahn, Myung-Ju,Wright, Elaine,Kim, Heung Tae,Kim, Joo-Hang,Kang, Jin Hyoung,Kim, Sang-We,Sherman, Steven,Walzer, Stefan Blackwell Pub. Asia 2011 Asia-Pacific journal of clinical oncology Vol.7 No.suppl2

<P>To indirectly compare real-life clinical effectiveness of bevacizumab + cisplatin-based therapy from the Safety of Avastin in Lung (SAiL) phase IV clinical trial with published evidence from the phase III clinical trial for pemetrexed + cisplatin among East Asian patients with non-squamous metastatic or recurrent non-small cell lung cancer (NSCLC).</P>

Court Ruling on the English Benchmark Requirement for Graduation in Taiwan

James M. Sims,Steven Chen 아시아영어교육학회 2019 The Journal of Asia TEFL Vol.16 No.1

Ultrathin compound semiconductor on insulator layers for high-performance nanoscale transistors

Ko, Hyunhyub,Takei, Kuniharu,Kapadia, Rehan,Chuang, Steven,Fang, Hui,Leu, Paul W.,Ganapathi, Kartik,Plis, Elena,Kim, Ha Sul,Chen, Szu-Ying,Madsen, Morten,Ford, Alexandra C.,Chueh, Yu-Lun,Krishna, Sanj Nature Publishing Group, a division of Macmillan P 2010 Nature Vol.468 No.7321

Over the past several years, the inherent scaling limitations of silicon (Si) electron devices have fuelled the exploration of alternative semiconductors, with high carrier mobility, to further enhance device performance. In particular, compound semiconductors heterogeneously integrated on Si substrates have been actively studied: such devices combine the high mobility of III??V semiconductors and the well established, low-cost processing of Si technology. This integration, however, presents significant challenges. Conventionally, heteroepitaxial growth of complex multilayers on Si has been explored??but besides complexity, high defect densities and junction leakage currents present limitations in this approach. Motivated by this challenge, here we use an epitaxial transfer method for the integration of ultrathin layers of single-crystal InAs on Si/SiO<SUB>2</SUB> substrates. As a parallel with silicon-on-insulator (SOI) technology, we use ??XOI?? to represent our compound semiconductor-on-insulator platform. Through experiments and simulation, the electrical properties of InAs XOI transistors are explored, elucidating the critical role of quantum confinement in the transport properties of ultrathin XOI layers. Importantly, a high-quality InAs/dielectric interface is obtained by the use of a novel thermally grown interfacial InAsO<SUB>x</SUB> layer (~1?nm thick). The fabricated field-effect transistors exhibit a peak transconductance of ~1.6?mS?쨉m<SUP>??1</SUP> at a drain??source voltage of 0.5?V, with an on/off current ratio of greater than 10,000.

UPS Flux Compensation Techniques for Transformer Inrush Reduction

Ming-Yang Yeh,Yu-Hsing Chen,Po-Tai Cheng,Steven Liao,Charles Tsai 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents two flux compensation designs for the uninterruptible power supply system. The objective of the flux compensation is to reduce the potential inrush current of the uninterruptible power supply-fed load transformer in the event of grid disturbances and load transformer engagement. The proposed methods utilize the existing voltage and current sensors, and voltage and current control loops of the uninterruptible power supply system for easy implementation. The application scenario is explained, and details of the flux compensation techniques are presented. Laboratory test results are provided for validation.