Browsing by Author "Ren, Yi"

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A Feasiblity Study on Developing IoT/M2M Applications over ETSI M2M Architecture
(2013-01-01)
Lin, Fuchun Joseph
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Ren, Yi
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Cerritos, Eduardo
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交大工研院聯合研發中心
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NCTU/ITRI Joint Research Center
A common service platform is considered as the key enabler to catalyze the development of IoT/M2M applications for a large variety of vertical markets such as smart energy, smart transportation, home and industry automation, eHealth and connected vehicles. This paper reports an initial effort at National Chiao Tung University in Taiwan with such an experimental approach. We first train our graduate students with an ETSI M2M architecture-compliant service platform OpenMTC from FOKUS, and then charter them with the tasks of developing diverse M2M applications. The effort is used as a feasibility study to investigate how useful the notion of a common service platform for IoT/M2M is and how urgent an international standard is required in defining such a platform. We intend to use the result of the study to create a suitable IoT/M2M curriculum for our students.
A Hint-based Random Access Protocol for mMTC in 5G Mobile Network
(2018-01-01)
Xu, Yining
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Ren, Yi
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Lin, Kate Ching-Ju
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Tseng, Yu-Chee
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資訊工程學系
With the increasing popularity of machine-type communication (MTC) devices, several new challenges are encountered by the legacy long term evolution (LTE) system. One critical issue is that a massive number of MTC devices trying to conduct random access procedures may cause significant collisions and long delays. In this work, we present a new random access mechanism by splitting the contention-based preambles in LTE into two logically disjoint parts, one for the user equipment (UE) being paged and the other for the UEs not being paged. Since the IDs of paged UEs are known by the base station, a novel hash-based random access, which we call hint, is possible. The main idea is to pre-allocate preambles to paged UEs in a contention-free manner and confines non-paged UEs to contend in a separate region. We further build a mathematical model to find the optimal ratio of pre-allocated preambles. Extensive simulations are conducted to validate our results.
A Novel Approach to Trust Management in Unattended Wireless Sensor Networks
(2014-07-01)
Ren, Yi
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Zadorozhny, Vladimir I.
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Oleshchuk, Vladimir A.
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Li, Frank Y.
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資訊工程學系
Unattended Wireless Sensor Networks (UWSNs) are characterized by long periods of disconnected operation and fixed or irregular intervals between sink visits. The absence of an online trusted third party implies that existing WSN trust management schemes are not applicable to UWSNs. In this paper, we propose a trust management scheme for UWSNs to provide efficient and robust trust data storage and trust generation. For trust data storage, we employ a geographic hash table to identify storage nodes and to significantly decrease storage cost. We use subjective logic based consensus techniques to mitigate trust fluctuations caused by environmental factors. We exploit a set of trust similarity functions to detect trust outliers and to sustain trust pollution attacks. We demonstrate, through extensive analyses and simulations, that the proposed scheme is efficient, robust and scalable.
A Novel Approach to Trust Management in Unattended Wireless Sensor Networks
(2014-07-01)
Ren, Yi
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Zadorozhny, Vladimir I.
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Oleshchuk, Vladimir A.
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Li, Frank Y.
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資訊工程學系
Unattended Wireless Sensor Networks (UWSNs) are characterized by long periods of disconnected operation and fixed or irregular intervals between sink visits. The absence of an online trusted third party implies that existing WSN trust management schemes are not applicable to UWSNs. In this paper, we propose a trust management scheme for UWSNs to provide efficient and robust trust data storage and trust generation. For trust data storage, we employ a geographic hash table to identify storage nodes and to significantly decrease storage cost. We use subjective logic based consensus techniques to mitigate trust fluctuations caused by environmental factors. We exploit a set of trust similarity functions to detect trust outliers and to sustain trust pollution attacks. We demonstrate, through extensive analyses and simulations, that the proposed scheme is efficient, robust and scalable.
A Robust and Flexible Access Control Scheme for Cloud-IoT Paradigm with Application to Remote Mobile Medical Monitoring
(2015)
Ren, Wei
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Ren, Yi
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Wu, Mu-En
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Lee, Chia-Jung
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資訊工程學系
Cloud computing paradigm is becoming very popular these days. However, it does not include wireless sensors and mobile phones which are needed to enable new emerging applications such as remote home medical monitoring. Therefore, a combined Cloud-Internet of Things (IoT) paradigm provides scalable on-demand data storage and resilient computation power at the cloud side as well as anytime, anywhere health data monitoring at the IoT side. As both the privacy of personal medical data and flexible data access should be provided, the data in the Cloud are always encrypted and access control must be operated upon encrypted data together with being fine-grained to support diverse accessibility. Since a plain combination of encryption before access control is not robust and flexible, we propose a scheme with tailored design. The scheme makes use of cipher-policy attributes based encryption to empower robustness and flexibility. The scheme describes a general framework to solve the secure requirements, and leaves the flexibility of concrete constructions intentionally.
APP: An Ultralightweight Scheme to Authenticate ONS and Protect EPC Privacy without Cryptography in EPCglobal Networks
(2013)
Ren, Wei
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Ma, Liangli
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Ren, Yi
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資訊工程學系
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Department of Computer Science
EPCglobal network is used to share product data between trading partners, which was proposed by EPCglobal. Object Name Service (ONS) in EPCglobal framework raises two critical security risks: the authenticity of IP addresses for Physical Markup Language (PML) servers and the privacy of Electronic Product Codes (EPCs). Existing work considers either the IP address authentication or the EPC privacy. In addition, that work mainly relies on cryptographic tools, in which key distribution is not a trivial task and also causes a large amount of computation overhead. In this paper, we make the first attempt to solve those two security risks together without relying cryptography. We propose a scheme, namely, APP (authenticate ONS and protect EPC privacy), to guarantee the authenticity of IP addresses for PML servers as well as EPC privacy and to maintain ultralightweight computation cost. Moreover, we give formal definition of the authenticity and the privacy in ONS context. The security achievements are strictly analyzed and proved. The extensive analysis results justify the applicability of the proposed scheme.
Applying Machine Learning to Head Gesture Recognition using Wearables
(2017-01-01)
Wu, Cheng-Wei
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Yang, Hua-Zhi
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Chen, Yan-Ann
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Ensa, Bajo
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Ren, Yi
Recently, some studies for head gestures recognition have been proposed, but most of them are based on image processing technology. Moreover, there is less focus on the use of wearable devices in recognizing head gestures. In this paper, we apply machine learning techniques to recognize some common head activities using a head-mounted wearable device. We use the wearable device to collect sensor data related to user's head activities. Then, we apply energy-based segmentation method on the collected data to find out the data segments where the activities may occur. Finally, we extract candidate features from the segments and feed them into a pre-trained classifier to identify the type of head gesture. We implement the prototype of above methods on Arduino platform and evaluate the efficiency of the proposed methods on real datasets. The experiment results show that our proposed methods can effectively and efficiently identify different types of head gestures with an average accuracy rate of 95%.
ASA: Adaptive VNF Scaling Algorithm for 5G Mobile Networks
(2018-01-01)
Ren, Yi
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Tuan Phung-Duc
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Liu, Yi-Kuan
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Chen, Jyh-Cheng
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Lin, Yi-Hao
5G mobile networks introduce Virtualized Network Functions (VNFs) to provide flexible services for incoming huge mobile data traffic. Compared with fixed capacity legacy network equipment, VNFs can be scaled in/out to adjust system capacity. However, hardware-based legacy network equipment is designed dedicatedly for its purpose so that it is more efficient in terms of unit cost. One challenge is to best use VNF resources and to balance the traffic between legacy network equipment and VNFs. To address this challenge, we first formulate the problem as a cost-performance tradeoff, where both VNF resource cost and system performance are quantified. Then, we propose an adaptive VNF scaling algorithm to balance the tradeoff. We derive the suitable VNF instances to handle data traffic with minimizing cost. Through extensive simulations, the adaptive algorithm is proven to provide good performance.
Congestion Control for Machine-Type Communications in LTE-A Networks
(2016-01-01)
Chang, Chia-Wei
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Lin, Yi-Hao
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Ren, Yi
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Chen, Jyh-Cheng
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資訊工程學系
Collecting data from a tremendous amount of Internet-of-Things (IoT) devices for next generation networks is a big challenge. A large number of devices may lead to severe congestion in Radio Access Network (RAN) and Core Network (CN). 3GPP has specified several mechanisms to handle the congestion caused by massive amounts of devices. However, detailed settings and strategies of them are not defined in the standards and are left for operators. In this paper, we propose two congestion control algorithms which efficiently reduce the congestion. Simulation results demonstrate that the proposed algorithms can achieve 20 similar to 40% improvement regarding accept ratio, overload degree and waiting time compared with those in LTE-A.
Design and Analysis of a Threshold Offloading (TO) Algorithm for LTE Femtocell/Macrocell Networks
(2016)
Chen, Wei-Han
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Ren, Yi
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Chen, Jyh-Cheng
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資訊工程學系
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Department of Computer Science
LTE femtocells have been commonly deployed by network operators to increase network capacity and offload mobile data traffic from macrocells. A User Equipment (UE) camped on femtocells has the benefits of higher transmission rate and longer battery life due to its proximity to the base stations. However, various user mobility behaviors may incur frequent signaling overhead and degrade femtocell offloading capability. To efficiently offload mobile data traffic, we propose a Threshold Offloading (TO) algorithm considering the trade-off between network signaling overhead and femtocell offloading capability. In this paper, we develop an analytical model to quantify the trade-off and validate the analysis through extensive simulations. The results show that the TO algorithm can significantly reduce signaling overhead at minor cost of femtocell offloading capability. Moreover, this work offers network operators guidelines to set offloading threshold in accordance with their management policies in a systematical way.
Design and Analysis of Deadline and Budget Constrained Autoscaling (DBCA) Algorithm for 5G Mobile Networks
(2016-01-01)
Than Phung-Duc
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Ren, Yi
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Chen, Jyh-Cheng
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Yu, Zheng-Wei
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資訊工程學系
In cloud computing paradigm, virtual resource autoscaling approaches have been intensively studied recent years. Those approaches dynamically scale in/out virtual resources to adjust system performance for saving operation cost. However, designing the autoscaling algorithm for desired performance with limited budget, while considering the existing capacity of legacy network equipment, is not a trivial task. In this paper, we propose a Deadline and Budget Constrained Autoscaling (DBCA) algorithm for addressing the budget-performance tradeoff. We develop an analytical model to quantify the tradeoff and cross-validate the model by extensive simulations. The results show that the DBCA can significantly improve system performance given the budget upper-bound. In addition, the model provides a quick way to evaluate the budget-performance tradeoff and system design without wide deployment, saving on cost and time.
Design and Analysis of the Key Management Mechanism in Evolved Multimedia Broadcast/Multicast Service
(2016-12)
Ren, Yi
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Chen, Jyh-Cheng
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Chin, Jui-Chih
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Tseng, Yu-Chee
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資訊工程學系
3GPP introduced the key management mechanism (KMM) in evolved multimedia broadcast/multicast service (eMBMS) to provide forward security and backward security for multicast contents. In this paper, we point out that KMM may lead to frequent rekeying and re-authentication issues due to eMBMS\'s characteristics: 1) massive group members; 2) dynamic group topology; and 3) unexpected wireless disconnections. Such issues expose extra load for both user equipment (UE) terminals and mobile operators. It seems prolonging the rekeying interval is an intuitive solution to minimizing the impact of the issues. However, a long rekeying interval is not considered the best operational solution due to revenue loss of content providers. This paper quantifies the tradeoff between the load of the UEs and the operators as well as the revenue loss of the content providers. Moreover, we emphasize how essential this rekeying interval has impacts on the problems. Using our proposed tradeoff model, the operators can specify a suitable rekeying interval to best balance the interest between the above three parties. The tradeoff model is validated by extensive simulations and is demonstrated to be an effective approach for the tradeoff analysis and optimization on eMBMS.
Design of a Self-Portrait Application with Sensor-Assisted Guiding for Smart Devices
(2013)
Lo, Chi-Chung
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Huang, Sz-Pin
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Ren, Yi
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Tseng, Yu-Chee
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資訊工程學系
Taking self-portrait on a smart device, such as a smart phone and a digital camera, is a lot of fun and can be easy when we know how. However, there are rare cases that we can get satisfied snapshots at our first try. Furthermore, the snapshots are usually stored on the camera. The user would not able to check the snapshots immediately on the remote side since she stands away the camera. In this paper, we propose a self-portrait application which enables a smart device to prevent faces from being cut out of the camera frame by giving suggestions to users until they are in a suitable position in the frame. In the same time, we enable the smart device to share the photos automatically to the remote device by machine-to-machine technique. The remote device can also control the camera to take photos again. The proposed application has been implemented on an Android smart phone.
Dynamic Auto Scaling Algorithm (DASA) for 5G Mobile Networks
(2016-01-01)
Ren, Yi
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Phung-Duc, Tuan
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Chen, Jyh-Cheng
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Yu, Zheng-Wei
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資訊工程學系
Network Function Virtualization (NFV) enables mobile operators to virtualize their network entities as Virtualized Network Functions (VNFs), offering fine-grained on-demand network capabilities. VNFs can be dynamically scale-in/ out to meet the performance desire and other dynamic behaviors. However, designing the auto-scaling algorithm for desired characteristics with low operation cost and low latency, while considering the existing capacity of legacy network equipment, is not a trivial task. In this paper, we propose a VNF Dynamic Auto Scaling Algorithm (DASA) considering the tradeoff between performance and operation cost. We develop an analytical model to quantify the tradeoff and validate the analysis through extensive simulations. The results show that the DASA can significantly reduce operation cost given the latency upper-bound. Moreover, the models provide a quick way to evaluate the cost-performance tradeoff and system design without wide deployment, which can save cost and time.
eHint: An Efficient Protocol for Uploading Small-Size IoT Data
(2017-01-01)
Chan, Tsung-Yen
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Ren, Yi
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Tseng, Yu-Chee
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Chen, Jyh-Cheng
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資訊工程學系
IoT (Internet of Things) has attracted a lot of attention recently. IoT devices need to report their data or status to base stations at various frequencies. The IoT communications observed by a base station normally exhibit the following characteristics: (1) massively connected, (2) lightly loaded per packet, and (3) periodical or at least mostly predictable. The current design principals of communication networks, when applied to IoT scenarios, however, do not fit well to these requirements. When a large number of devices contend to send small packets, the signaling overhead is not cost-effective. To address this problem, our previous work [ 1] proposes the Hint protocol, which is slot-based and schedule-oriented for uploading IoT devices' data. In this work, we extend [ 1] to support data transmissions for multiple resource blocks. We assume that the uplink payloads from IoT devices are small, each taking very few slots (or resource blocks), but devices are massive. The main idea is to "encode" information in a tiny broadcast that allows each device to "decode" its transmission slots, thus significantly reducing transmission overheads and contention overheads. Our simulation results verify that the protocol can significantly increase channel utilization compared with traditional schemes.
Flowtable-Free Routing for Data Center Networks: A Software-Defined Approach
(2017-01-01)
Ren, Yi
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Tsai, Tsung-Han
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Huang, Ji-Cheng
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Wu, Cheng-Wei
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Tseng, Yu-Chee
The paradigm shift toward SDN has exhibited the following trends: (1) relying on a centralized and more powerful controller to make intelligent decisions, and (2) allowing a set of relatively dumb switches to route packets. Therefore, efficiently looking up the flowtables in forwarding switches to guarantee low latency becomes a critical issue. In this paper, following the similar paradigm, we propose a new routing scheme called KeySet which is flowtable-free and enables constant-time switching at the forwarding switches. Instead of looking up long flowtables, KeySet relies on a residual system to quickly calculate routing paths. A switch only needs to do simple modular arithmetics to obtain a packet's forwarding output port. Moreover, KeySet has a nice fault-tolerant capability because in many cases the controller does not need to update flowtables at switches when a failure occurs. We validate KeySet through extensive simulations by using general as well as Facebook fat-tree topologies. The results show that the KeySet outperforms the KeyFlow scheme [1] by at least 25% in terms of the length of the forwarding label. Moreover, we show that KeySet is very efficient when applied to fat-trees.
From Spotting the Difference to Spotting Your Difference
(2015-01-01)
Chan, Tsung-Yen
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Chang, Po-Yen
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Ren, Yi
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Tseng, Yu-Chee
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資訊工程學系
E-healthcare games are a new patient care tool for providing fun, on-line monitoring enabled lifestyle, and a way for redefining traditional doctor-patient relationship. In this work, we demonstrate the use of intelligent sensors to capture patient behaviors for home healthcare. We design a new e-healthcare game user interface, iCube, for monitoring and recording patient activities. The iCube is a 3D game which has six display panels on the surfaces of a 3D cube embedded with a zigbee interface and some sensors for behavior monitoring. To prove its concept, we implement a Spot the Difference game. When a player is playing the game, the iCube can capture the player's hand shaking, rolling response, and visual capability. Those collected data are then sent to a database for spotting the progress/difference of the player over a long period time.
Give Me a Hint: An ID-Free Small Data Transmission Protocol for Dense IoT Devices
(2017-01-01)
Ren, Yi
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Wu, Ren-Jie
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Huang, Teng-Wei
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Tseng, Yu-Chee
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資訊工程學系
IoT (Internet of Things) has attracted a lot of attention recently. IoT devices need to report their data or status to base stations at various frequencies. The IoT communications observed by a base station normally exhibit the following characteristics: (1) massively connected, (2) lightly loaded per packet, and (3) periodical or at least mostly predictable. The current design principals of communication networks, when applied to IoT scenarios, however, do not fit well to these requirements. For example, an IPv6 address is 128 bits, which is much longer than a 16-bit temperature report. Also, contending to send a small packet is not cost-effective. In this work, we propose a novel framework, which is slot-based, schedule-oriented, and identity-free for uploading IoT devices' data. We show that it fits very well for IoT applications. The main idea is to bundle time slots with certain hashing functions of device IDs, thus significantly reducing transmission overheads, including device IDs and contention overheads. The framework is applicable from small-scale body-area (wearable) networks to large-scale massively connected IoT networks. Our simulation results verify that this framework is very effective for IoT small data uploading.
Hey! I Have Something for You: Paging Cycle Based Random Access for LTE-A
(2018-01-01)
Hsu, Chia-An
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Ren, Yi
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Lin, Kate Ching-Ju
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Tseng, Yu-Chee
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資訊工程學系
The surge of M2M devices imposes new challenges for the current cellular network architecture, especially in radio access networks. One of the key issues is that the M2M traffic, characterized by small data and massive connection requests, makes significant collisions and congestion during network access via the random access (RA) procedure. To resolve this problem, in this paper, we propose a paging cycle-based protocol to facilitate the random access procedure in LTE-A. The high-level idea of our design is to leverage a UE's paging cycle as a hint to preassign RA preambles so that UEs can avoid preamble collisions at the first place. Our rpHint has two modes: (1) collision-free paging, which completely prevents cross-collision between paged user equipments (UEs) and random access UEs, and (2) collision-avoidance paging, which alleviates cross-collision. Moreover, we formulate a mathematical model to derive the optimal paging ratio that maximizes the expected number of successful UEs. This analysis also allows us to adapt dynamically to the better one between the two modes. We show via extensive simulations that our design increases the number of successful UEs in an RA procedure by more than 3x as compared to the legacy RA scheme of the LTE.
How to Authenticate a Device? Formal Authentication Models for M2M Communications Defending against Ghost Compromising Attack
(2013)
Ren, Wei
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Yu, Linchen
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Ma, Liangli
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Ren, Yi
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資訊工程學系
In Machine-to-Machine (M2M) communications, authentication of a device is of upmost importance for applications of Internet of Things. As traditional authentication schemes always assume the presence of a person, most authentication technologies cannot be applied in machine-centric M2M context. In this paper, we make the first attempt to formally model the authentication in M2M. We first model four attacking adversaries that can formulate all possible attacks in M2M, which are channel eavesdropping attack, credential compromise attack, function compromise attack, and ghost compromise attack. Next, we propose four models to tackle those corresponding adversaries, namely, credential-based model, machine-metrics-based model, reference-based model, and witness-based model. We also illustrate several concrete attacking methods and authentication approaches. We proof the authentication security for all proposed models and compare them for clarity. Our models present soundness and completeness in terms of authentication security, which can guide the design and analysis of concrete authentication protocols. Particularly, we construct a uniform authentication framework for M2M context and point out all possible authentication mechanisms in M2M.