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Making the world a better place with
innovations in network, system and service
technologies.

Network Systems and

Services Lab

Lab

Research Faculty
Jan-Ming Ho Our research address several aspects of network systems and services, including the
Research Fellow design of high-quality, energy-efficient, and secure environments for wireless sensing
and networking, improving delay-tolerant network protocols, leveraging human com-
Ling-Jyh Chen putation capabilities to address key challenges, developing critically needed information
Associate Research Fellow and communication technologies for disaster management, and seeking solutions to
Meng Chang Chen network computational problems when providing large-scale financial risk management
Research Fellow services.
Sheng-Wei Chen
Associate Research Fellow Wen-Tsuen Chen
Wen-Tsuen Chen Mobile video streaming has become a dominant service, and consequently traffic sched-
Distinguished Research Fellow uling has become an important issue to ensure fairness and provide better quality of
Tyng-Ruey Chuang service (QoS). Existing QoS schemes are not designed for video traffic, and they do not
Associate Research Fellow consider the different features of videos; this inevitably results in a bad experience for the
Jane W. S. Liu user. Thus, we have used software-defined networking (SDN) to build architecture to re-
Chair Research Fellow serve bandwidth, and route video traffic based on network resources and video features,
such as bit rate. Through this process, we can guarantee video quality, and also improve
network utilization.

Transmission mechanisms in the traditional personal communication service (PCS) net-
works and in the next-generation broadband all-IP networks are different. Therefore, the
mobility models used in traditional PCS networks are not adaptive to 4G cases. In order to
capture the essence of 4G network behavior, we propose a new mobility model to derive
analytical results for telecommunications traffic. We observe that the derived analytical
results can bring significant insight into the department of network infrastructure.

We also present a long-range wake-up radio (LRWUR), and propose an overall metric for
evaluating the Internet of Things (IoT) and wireless sensor networks (WSN). Experimental
results have shown that block orthogonal codes improve both the communication range
and packet error rate, thereby enhancing the wireless sensor node’s performance and
reducing the cost of maintenance for IoT and WSN applications.

As regards security and privacy problems in intelligent sensing and networking applica-
tions, we are addressing the challenges of access control in both WSN and online social
networks (OSNs). The main challenges posed are not only the unique security and pri-
vacy problems in wireless networks, but also the computation and communication ef-
ficiencies required for energy-constrained devices (e.g., wireless sensor nodes and smart
phones). We aim to design stronger secure sensing and networking systems which do
not consume the limited resource of mobile devices.

Ling-Jyh Chen

Furthermore, we study networked sensing systems, with an emphasis on both energy
efficiency and large-scale sensor data management. We have developed an adaptive GPS
scheduling algorithm to prolong the lifespan of GPS-enabled mobile sensors, and have
designed a hybrid location-sensing approach to strike a balance between power con-
sumption and information accuracy by combining multiple sensors of different energy
profiles and data granularity. We have proposed a lightweight and lossless data compres-
sion algorithm for spatio-temporal data management, and designed a set of data query
algorithms to support spatio-temporal data computation using the compressed data di-
rectly. The results of our research have been implemented in two real-world networked

34 研究群 Research Laboratories