Lin Y.-B.,National Chiao Tung University |
Lin P.-J.,NCTU |
Sung Y.,NCTU |
Chen Y.-K.,Chunghwa Telecom |
And 4 more authors.
IEEE Wireless Communications | Year: 2013
Long Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX) are two major technologies toward next-generation mobile broadband standards, which are both expected to provide higher throughput and lower transmission latency for mobile users. This article measures and compares the latency and the throughput of Time Division - Long Term Evolution (TD-LTE), WiMAX, and third-generation (3G) systems based on several technical trials. Our quantitative measures and comparisons provide guidelines for the operators to deploy their future networks. © 2002-2012 IEEE.
Ho C.-Y.,National Chiao Tung University |
Tseng C.-C.,NCTU |
IEEE Communications Letters | Year: 2011
In this article, an NAT-compatibility testbed is designed to automatically conduct the repeated experiments, collect the test results, and verify the direct connection rate (DCR) of any NAT traversal programs. Achieving a high DCR is important because using relays may unnecessarily increase the bandwidth cost, processing load of the relay servers, and the end-to-end packet delay. The NAT-compatibility testbed is constructed with 4 components: two peers, an automatic execution mechanism, NAT devices, and signaling/intermediate servers such as STUN, TURN, and SIP. It is also called the fully meshed testbed because the test result of all NAT combinations is a square. It measures the DCR of ICE, KeyStone, and PJNATH as 53.7%, 59.87%, and 50.93%, respectively. Experimental results show that asymmetric and unexpected direct connectivity check results occur in the real Internet. In order to enhance NAT traversal capability, the findings, like "port prediction" and "call-role sensitivity problem," are also described in the experimental results. © 2011 IEEE.
Ho C.-Y.,National Chiao Tung University |
Tseng C.-C.,NCTU |
Wang J.-T.,Industrial Technology Research Institute of Taiwan |
IEEE Communications Letters | Year: 2011
In this article, we first depict the call-role sensitivity problem in Network Address Translation (NAT) traversal, and then propose an approach to resolving the problem. The problem is whether a direct connection can be found between two peers across NATs mainly depends on the NAT type at the caller's side. We propose the extra-candidate connectivity check where both peers initiate a direct connectivity check to eliminate the effect of the call role. We have implemented the extra-candidate connectivity check and conducted experiments with 18 different NATs. Experimental results show that our approach can indeed resolve the call-role sensitivity problem, and maximize the direct connectivity rate (DCR) which is improved by 18.71% from the original scheme. © 2011 IEEE.
News Article | October 28, 2016
MENLO PARK, CA--(Marketwired - October 24, 2016) - ONOS Project, the rapidly growing open source community advancing the software-defined networking (SDN) OS for service providers with high availability, scale and performance and the right abstractions to create apps and services, today announced BII, Canonical, NCTU and UPMC have joined as collaborators. To build on the continued project momentum, more than 215 ONOS® developers focused on coding and testing will converge in Paris from November 2-4 for the project's first large-scale developer summit, ONOS Build 2016. "ONOS Build 2016 will offer the unique opportunity for ONOS users and contributors across the globe to meet, align, plan and hack together in-person," said Bill Snow, VP of engineering for ON.Lab. "Open to members and non-members alike, attendees will have the chance to talk directly with the ONOS core architects and Technical Steering Team, collaborate on ideas that will directly impact the future of ONOS, and promote their work among the community." The ONOS Build 2016 agenda includes a mix of sharing the ONOS roadmap, social activities for the community to bond, and hacking activities to help deliver specific features in the pipeline. The event will feature keynotes and industry panelists from ONOS community partners and collaborators Ciena, Create-Net, DT, GARR, Huawei, NOKIA Bell Labs, NTT Communications, ON.Lab, Radisys and UPMC. Topics for discussion will include basics of the ONOS architecture, northbound and southbound protocols, deployments, application development, performance and testing, community planning and the Ambassador program. Click here to learn more about the confirmed speakers. A separate Community Showcase track will be devoted to members and ONOS Brigade teams presenting updates on interesting new features developed by and for the ONOS community through open source collaboration. For example, the Dynamic Configuration Brigade has focused on building a vendor-agnostic driver into ONOS that allows automatic discovery and activation of NETCONF-enabled devices and services into the network as long as they expose a Yang Model. Click here to read more about the ONOS Brigades, and here to view the complete ONOS Build 2016 agenda. To obtain an ONOS Build ticket, complete the online registration form. ONOS Build 2016 is free for students and ONOS contributors. General admission costs $400 USD. ONOS is grateful for its generous sponsors who are helping organize the event. These include Platinum sponsors Ciena, Fujitsu, and Huawei, Gold sponsors Kisti and Radisys, and Silver sponsors ADARA Networks and Gandi. If interested in sponsoring ONOS Build 2016 or future Build events, please contact email@example.com. More about the new ONOS collaborators: BII: BII Group Holdings Ltd. centered on the core of technical research and development, seated on the basis of testing service, and navigated by internationalization and marketization, is a global open platform for internet infrastructure technologies with a focus on IPv6, Domain Name System (DNS), SDN and Internet of Things (IoT). Canonical: Canonical is the company behind Ubuntu, the leading OS for container, cloud, scale-out and hyperscale computing. 65% of large-scale OpenStack deployments are on Ubuntu, using both KVM and the pure-container LXD hypervisor for the world's fastest private clouds. Canonical provides enterprise support and services for commercial users of Ubuntu. NCTU: National Chiao Tung University (NCTU) is a prestigious university known for its special strengths in the areas of computer science and electronics engineering. Its highly-reputable computer science department, which is the largest one in Taiwan, will participate in the ONOS Project with a focus on SDN-IP. UPMC: The University Pierre and Marie Curie LIP6 computer science research laboratory is dedicated to application modeling and testing, as well as implementation and validation through academic and industry partnerships. Currently, LIP6 is strategizing data consistency for distributed network control-plane systems, and enhancing SDN southbound interfaces. Redefining network economics, ONOS provides the only SDN control plane that can support both disruptive and incremental SDN for service providers and enterprises seeking to virtualize and optimize their networks to keep agile pace with the explosion of mobile devices, video and big data applications. The rapidly growing and diverse ONOS community comprises a core engineering team at ON.Lab, along with developers from service providers, vendors and Research and Educational Networks spanning across industries. Whether an individual or an organization, as an open source project all are encouraged to get involved with the growing ONOS community and help contribute to the project today. ONOS® is the open source SDN networking operating system for Service Provider networks architected for high performance, scale and availability. The ONOS ecosystem comprises ON.Lab, organizations that are funding and contributing to the ONOS initiative, and individual contributors. These organizations include AT&T, China Unicom, Comcast, Google, NTT Communications Corp., SK Telecom Co. Ltd., Verizon, Ciena Corporation, Cisco Systems, Inc., Ericsson, Fujitsu Ltd., Huawei Technologies Co. Ltd., Intel Corporation, NEC Corporation, Nokia, Radisys and Samsung. See the full list of members, including ONOS' collaborators, and learn how you can get involved with ONOS at onosproject.org. ONOS is an independently funded software project hosted by The Linux Foundation, the nonprofit advancing professional open source management for mass collaboration to fuel innovation across industries and ecosystems.
Lin H.-C.,NCTU |
Liu S.S.-Y.,NCTU |
IEEE/ACM International Conference on Computer-Aided Design, Digest of Technical Papers, ICCAD | Year: 2015
The issue on reliability of the device becomes more critical as power density of device progressively increases with advancement of technology nodes. Smaller transistor and hence thinner gate oxide implies transistors are more vulnerable against an Electrostatic Discharge (ESD) event. Among the test models in ESD, Charged Device Model (CDM) has greater potential to cause catastrophic damage to the device due to its faster and larger discharging current. To protect against a CDM event, power clamps are placed across the design to offer a low resistance discharge path. However, conventional power clamp placement method to place power clamps generally relies on design experience. In this work, we propose a power clamp placement algorithm that places power clamp at strategic location which can effectively minimize number of power clamps while achieving better protection against a CDM event compared to conventional approach. © 2014 IEEE.
Protasov D.Y.,RAS Semiconductor Physics Institute |
Jian W.-B.,NCTU |
Svit K.A.,RAS Semiconductor Physics Institute |
Duda T.A.,RAS Semiconductor Physics Institute |
And 4 more authors.
Journal of Physical Chemistry C | Year: 2011
Aggregation clusters of CdS quantum dots (QDs) on the highly ordered pyrolytic graphite substrate were investigated by atomic force microscopy and scanning tunneling microscopy. QDs were initially formed within Y-type Langmuir-Blodgett (LB) films of cadmium behenate. The LB matrix was then removed by annealing. To study the process of QD assembly, the density of QDs in the initial film was varied systematically by increasing the number of monolayers (MLs) from 1 to 20 ML. It was found that, at a small LB ML number, only a small part of CdS molecules form into QDs by diffusion along the plane of LB layers. With an increase of the LB ML number, the interlayer diffusion arises that leads to almost full binding of CdS molecules into QDs. The individually standing QDs were formed on the substrate for 1 and 2 ML samples. The QD size distributions of the samples with a small ML number are broader than that predicted by the two-dimensional Lifshitz-Slezov diffusion model. With an increase of the LB matrix thickness, QDs begin to assemble into clusters, revealing a ribbon structure due to diffusion-limited aggregation, and for the 20 ML LB matrix, a submonolayer QD film arises. By analyzing the occurrence of QDs as a function of aggregation number, pair bondings were estimated to be about 34 and 62 meV for the 4 and 8 ML samples, respectively. © 2011 American Chemical Society.
Chang W.-T.,Asia University, Taiwan |
Proceedings - 2015 International Conference on Network and Information Systems for Computers, ICNISC 2015 | Year: 2015
IEEE 802.11e is an extension for media access control in wireless network. It is used for different Quality of Service requirement for different transmission application. But it assumes that all terminals operate in the same transmission speed. But when terminals use different transmission speeds, the access mechanism, EDCA, can not perform to its design purposes. Because the parameters designed for the four different categories can not be adapted according to the transmission speed. For high priority application, it is given a fixed transmission time, this will make the terminal with low speed difficult to achieve the required QoS due to insufficient time to transmit large packet. However, for low priority application, the system will be occupied by terminal with slow transmission speed when transmitting a long packet. This will affect the real time requirement of the QoS service and eventually reduce the total system performance. This paper will address the above two issues and try to purpose methods to improve it. First, a method is used to reduce the time that a low speed terminal will take when transmitting low priority data. Secondly, another method is used to enhance the QoS for all terminals with different transmission speed. With those two methods, we can obtain better throughput and better QoS for the WiFi system. © 2015 IEEE.
Cheng T.-C.,National Chung Cheng University |
Liao Y.-T.,NCTU |
Tsai T.-H.,National Chung Cheng University
2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015 | Year: 2015
This paper presents an integration of the capacitive micromachined ultrasonic transducers (CMUTs) and the transimpedance amplifier in medical ultrasound systems. The proposed CMUT and the sensing circuits are both fabricated on the same chip in a 0.18μm CMOS MEMS technology. Two interlayer metal structures are proposed to improve the sensitivity. The CMUTs are designed with 2MHz cells for medical diagnosis. The conversion efficiency of the CMUTs is 4 times and 1.8 times higher than that in the published structures. © 2015 IEEE.
Ou Y.-C.,Institute of Physics |
Zhuravlev K.S.,RAS Semiconductor Physics Institute |
Fang J.,Binghamton University State University of New York |
Journal of Physical Chemistry C | Year: 2010
Although self-organization of semiconductor nanocrystals (or quantum dots) into 3D superlattices and exploration of their collective optical, magnetic, and transport properties have been demonstrated, little is known about the underlying physics of self-assembly, growth mechanisms, and interdot-coupling- induced collective properties. Here we report a facile way of preparing nanocrystal-assembled 2D islands by drop-casting nanocrystal suspension on a hot substrate. Growth mechanisms such as scaling function, spinodal decomposition phase separation, and diffusion-limited aggregation are investigated based on the observation of quasi-monolayer coverage. After a curve fitting to several theoretical growth models, the pair bond (interaction) energy, critical nucleus size, and the phase of growth patterns were determined. Moreover, by heating the substrate and controlling the concentration of nanocrystal suspension, the spinodal decomposition and diffusion-limited aggregation can be tuned to modulate growth patterns of 2D nanocrystal islands. The interplay of these two mechanisms results in a variation of wavelength in spinodal growth patterns and of fractal pattern dimensions. By using this experimental approach, various sizes and shapes of nanocrystal-assembled 2D islands can be deposited on a flat surface of either graphite or gold. © 2010 American Chemical Society.
Ho C.-T.,Macronix Intl. Co. |
Lee Y.-M.,NCTU |
Wei S.-H.,NCTU |
Proceedings of the International Symposium on Physical Design | Year: 2014
The power grid needs to be frequently analyzed during the design process of power distribution network. Hence, an effective method being able to capture its transient behavior is desired for designers. This work utilizes macro modeling techniques, sparse recovery mechanisms, a proposed pseudo-node value estimation method, and an adaptive error control procedure to develop an efficient and reliable incremental power grid transient simulator. This incremental simulator not only can deal with adjusted values of the circuit elements but also can handle modified topologies of the design.