Browsing by Author "Chuang, Yi-Ta"

Now showing 1 - 20 of 20

A Crowdsourcing-based Road Anomaly Classification System
(2016)
Wang, Ru-Yu
;
Chuang, Yi-Ta
;
Yi, Chih-Wei
;
資訊工程學系
;
Department of Computer Science
Road networks are the most important facility to the public transportation in modern cities. Governments around the world allocate large amounts of budgets for the pavement maintenance every year. In this paper, we proposed a crowd-sourcing solution to categorize road anomalies into safety related anomalies such as speed bumps and rumble strips, and dangerous anomalies such as bumps and potholes. The proposed system is composed of three parts: a smart probe car crowds (SPC-crowd) that serve as the anomaly data source; cloud servers that are the core for the anomaly classification; and application services that provide various innovative applications to facilitate the pavement maintenance. To support the crowdsourcing procedure, in the SPC-crowd side, we proposed cross-SPC techniques by adopting the underdamped oscillation model (UOM). In the cloud side, a supervised learning classification model was adopted on the anomaly data generated from the SPC-crowd. To validate the proposed system, extensive field trial was performed. The experimental results shown that our system can facilitate the pavement maintenance through the crowdsourcing solution.
A Fuzzy Logic-Based Routing for Delay-Tolerant Heterogeneous Networks
(2009)
Huang, Chenn-Jung
;
Shen, Hung-Yen
;
Liao, Jia-Jian
;
Hu, Kai-Wen
;
Yang, Dian-Xiu
Delay Tolerant Network (DTN) is an intermittently connected mobile wireless network in which the connectivity between nodes changes frequently due to nodes\' movement. Recently, there have been a lot of researches working on this area. However, to the best of our knowledge, no work has addressed on the DTN routing which focuses on the heterogeneous network environment in the literature. In this work, we propose a prediction based routing protocol for the heterogeneous delay tolerant networks wherein edge servers are distributed over the borders of the different network domains. A location prediction algorithm based on the user online logs to intelligently estimate the most possible future location of the destination, if the destination is currently unavailable. Then an edge server selection algorithm based on fuzzy logic system is exploited to select the close-by intermediate node on the path to the destination so that the messages can be saved temporarily for the destination after the location of the destination is predicted. The experimental results exhibit that the proposed routing protocol can efficiently deliver the message under limited buffer space, comparing with two representative delay tolerant network routing protocols in the literature. The scalability of the proposed work is also confirmed in the simulations.
A hybrid priority-based video-on-demand resource sharing scheme
(2008-06-25)
Huang, Chenn-Jung
;
Chuang, Yi-Ta
;
Guan, Chih-Tai
;
Luo, Yun-Cheng
;
Hu, Kai-Wen
Video-on-demand (VoD) environments frequently batch video requests to decrease I/O demand and increase throughput. Since users may leave due to waiting too long, a good video scheduling policy has to consider not only the batch size, but also the user defection probabilities and waiting times. Moreover, a practical VoD resource sharing scheme should endeavor to provide some free streams to serve a high-priority clients requests immediately, since the high-priority clients might pay for the requested video. To tackle these problems, this work proposes a hybrid resource sharing model that integrates controlled multicasting and hatching. The proposed hybrid model applies a bandwidth borrowing and reserving scheme to give high-priority clients a prompt service, while still providing low-priority clients with a reasonable service. Furthermore, a novel probability model-based scheduling policy is proposed to alleviate the user defection behavior and unfairness issue. Experimental results demonstrate that the proposed resource sharing scheme is effective and feasible in terms of blocking probability of high-priority clients, the defection probability, service delay time and fairness to low-priority users. (C) 2008 Elsevier B.V. All rights reserved.
A SCALABLE ROUTING FOR DELAY-TOLERANT HETEROGENEOUS NETWORKS
(2012-01-01)
Huang, Chenn-Jung
;
Chen, Heng-Ming
;
Lin, Chin-Fa
;
Liao, Jia-Jian
;
Hu, Kai-Wen
A Delay Tolerant Network (DTN) is an intermittently connected mobile wireless network in which the connectivity between nodes changes frequently, due to the nodes' movement. Recently, there have been a lot of researchers working in this area. However, to the best of our knowledge, no work has addressed itself specifically to DTN routing within heterogeneous network environments. In this work, we propose a prediction-based routing protocol for heterogeneous delay tolerant networks, wherein edge servers are distributed over the borders of the different network domains. First, a location prediction algorithm based on user online logs is used to intelligently estimate the most probable future location of a destination, if the destination is currently unavailable. Then, an edge server selection algorithm, based on fuzzy logic, is employed to select a close-by intermediate node along the path to the destination, so that messages can be saved temporarily once the destination's location has been predicted. The experimental results show that the proposed routing protocol can efficiently deliver a message under limited buffer space, compared with other two representative delay tolerant network routing protocols found in the literature. The scalability of the proposed model is also confirmed in the simulations.
A Study on Wearable Electrocardiograph
(2015)
Tsai, Hsin-Hsi
;
Chuang, Yi-Ta
;
Yi, Chih-Wei
;
Wang, Yi-Chang
;
資訊工程學系
The emergence of wearable devices based on advances in MEMS and low-energy technologies makes low-cost sustained physiological monitoring possible and brings health care into a new territory. But until now, most wearable devices for physiological monitoring do not have FDA approval and the measured data may have some level of noise. In this work, to understand the feasibility of applying wearable electrocardiograph for heart activity monitoring during jogging, we propose a jogging monitoring system based on wearable devices and provide some experimental results. First, the proposed jogging monitoring system is sketched. Next, the traditional ECG tests and the fundamental ECG morphology are introduced. And then, a QRS detection algorithm is introduced and implemented to process ECG data. Last, we collect ECG data by a wearable device in jogging, and some MLII lead ECG records from the MIT-BIH database are selected for comparison. The accuracy of the implemented QRS detection algorithm against both data sets is provided.
An adaptive bandwidth reservation scheme for 4G cellular networks using flexible 2-tier cell structure
(2010-09-01)
Huang, Chenn-Jung
;
Shen, Hung-Yen
;
Chuang, Yi-Ta
;
資訊工程學系
;
Department of Computer Science
Many mechanisms based on bandwidth reservation have been proposed in the literature to decrease connection dropping probability for handoffs in cellular communications. The handoff events occur at a much higher rate in packet-switched fourth generation mobile communication networks than in traditional cellular systems. An efficient bandwidth reservation mechanism for the neighboring cells is therefore critical in the process of handoff during the connection of multimedia calls to avoid the unwillingly forced termination and waste of limited bandwidth in fourth generation mobile communication networks, particularly when the handoff traffic is heavy. In this paper, an adaptive two-tier scheme, which employs grey prediction theory and swarm intelligence techniques, is proposed to reduce the forced termination probability of multimedia handoffs. The simulation results show that the proposed scheme can achieve superior performance than the representative bandwidth-reserving schemes in the literature when performance metrics are measured in terms of the forced termination probability for the handoffs, the call blocking probability for the new connections and bandwidth utilization. (C) 2010 Elsevier Ltd. All rights reserved.
An Adaptive QoS-Aware Inter-Vehicle Routing in Vehicular Networks
(2008)
Huang, Chenn-Jung
;
Chuang, Yi-Ta
;
Yang, Dian-Xiu
;
資訊工程學系
;
Department of Computer Science
The transmission technology for intelligent transportation systems can typically classified into two categories, namely, road-to-vehicle communication (RVC) and inter-vehicle communication (IVC). This work proposes an adaptive QoS aware roadside base station assisted routing mechanisms to establish a routing path in IVC with assistance of roadside base station. A link failure prevention mechanism is employed to effectively construct alternative routing path required by the volatile network topology in vehicular ad hoc networks. Besides, a bandwidth consumption predictor is presented to avoid dropping data packets owing to inadequate bandwidth during handoffs. A PSO-tuned fuzzy logic system is proposed to compute the link break and congestion indicator in the route construction process. Simulation results demonstrate the effectiveness and feasibility of the proposed work.
Calorie Map: An Activity Intensity Monitoring System based on Wireless Signals
(2017-01-01)
Chiang, Ting-Hui
;
Chuang, Yi-Ta
;
Ke, Chia-Liang
;
Chen, Ling-Jyh
;
Tseng, Yu-Chee
Recently, elder care services, especially for those with chronic diseases, have become an important application in the field of IoT. Several studies have reported that the progress of chronic diseases can be slowed down effectively by moderate physical activities. In this paper, we propose an activity intensity monitoring system to support continuous monitoring of indoor calorie consumption. The system uses wireless signals to infer calorie burned in walking. In the proposed system, Bluetooth smart beacons are deployed in various spaces of a house. The elders who wear smart wristbands are continuously monitored for their locations by received wireless signals. The system has the following features. First, it utilizes wireless signals as location and activity intensity indicators; inertial sensors are only used in the training stage. Second, it is semi-training free and only needs relatively short training time to start using the monitoring services. Finally, the system is map-free, in the sense that it can be easily deployed without constructing the interior map of the house. A prototype system is implemented on a smartphone to evaluate the feasibility of the proposed system.
Developing an Intelligent Diagnosis and Assessment E-learning Tool for Introductory Programming
(2008)
Huang, Chenn-Jung
;
Chen, Chun-Hua
;
Luo, Yun-Cheng
;
Chen, Hong-Xin
;
Chuang, Yi-Ta
Recently, a lot of open source e-learning platforms have been offered for free in the Internet. We thus incorporate the intelligent diagnosis and assessment tool into an open software e-learning platform developed for programming language courses, wherein the proposed learning diagnosis assessment tools based on text mining and machine learning techniques are employed to alleviate the loading of the teachers. Experiments were conducted in two introductory-undergraduate programming courses to examine the effectiveness of the proposed diagnosis and assessment tools. The learners' work including the source code and comments were processed by the proposed text mining and machine learning techniques. This system also provides immediate feedback and high-quality evaluation results to guide the learners with poor performance. Our experimental results reveal that the proposed work can effectively assist the low-ability learners.
Discovering Phase Timing Information of Traffic Light Systems by Stop-Go Shockwaves
(2015-01-01)
Chuang, Yi-Ta
;
Yi, Chih-Wei
;
Tseng, Yu-Chee
;
Nian, Chia-Sheng
;
Ching, Chia-Hao
The cycle lengths and signal transition time of Traffic Light Systems (TLS\'s), or known as the Phase Timing Information (PTI), play a key role in modern transportation systems. However, such information is not always available to the public. In this paper, we propose a crowdsourcing approach to solve this problem by exploiting the stop and go events, abbreviated by SG events, of vehicles on roads happening in front of target traffic lights. The PTI discovery problem is formulated by allowing only part of the vehicles participating in the discovery process. The proposed framework starts with discovering SG events, followed by collapsing these events over multiple signal cycles into one and calculating PTI information through a shockwave technique. The crowdsourcing part may be directly implemented on smartphones. The proposed framework was verified via field trials and simulations. Our simulation results showed that, even with a low penetration rate around 3.8 percent, the root mean square errors of the cycle length, green light and red light signal transition time of a TLS are 0. 04, 1.3 and 5.8 seconds, respectively. The achieved accuracy can be helpful in many PTI-enabled applications.
File Transfer for Mobile Devices in Heterogeneous Radio Networks
(2010)
Yi, Chih-Wei
;
Yang, Shau-Shiuan
;
Lin, Yi-Bing
;
Chuang, Yi-Ta
;
Liu, Pin-Chuan
In the past, although mobile devices were equipped with multiple radio interfaces, for the sake of power saving, only one was activated for data transmission. The idea of concurrent transmission via multiple radio interfaces has not been seriously studied. However, nowadays, power consumption no longer is a problem in many application scenarios, e. g. VANETs. In this work, we investigate the performance improvement of concurrent file transfer over two heterogeneous radio networks, e. g. WiFi and 3G. The traditional File Transfer Protocol is modified to utilize two heterogeneous radio connections and experiments are executed over the Internet and a 3G data network to measure the latency and average bandwidth. Our results show that it is possible to integrate the bandwidth of both radio networks.
Implementation of call admission control scheme in next generation mobile communication networks using particle swarm optimization and fuzzy logic systems
(2008-10-01)
Huang, Chenn-Jung
;
Chuang, Yi-Ta
;
Yang, Dian-Xiu
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
In the present and next generation wireless networks, cellular system remains the major method of telecommunication infrastructure. Since the characteristic of the resource constraint, call admission control is required to address the limited resource problem in wireless network. The call dropping probability and call blocking probability are the major performance metrics for quality of service (QoS) in wireless network. Many call admission control mechanisms have been proposed in the literature to decrease connection dropping probability for handoffs and new call blocking probability in cellular communications. In this paper, we proposed an adaptive call admission control and bandwidth reservation scheme using fuzzy logic control concept to reduce the forced termination probability of multimedia handoffs. Meanwhile, we adopt particle swarm optimization (PSO) technique to adjust the parameters of the membership functions in the proposed fuzzy logic systems. The simulation results show that the proposed scheme can achieve satisfactory performance when performance metrics are measured in terms of the forced termination probability for the handoffs, the call blocking probability for the new connections and bandwidth utilization. (C) 2007 Elsevier Ltd. All rights reserved.
iTraffic: A Smartphone-based Traffic Information System
(2013)
Chuang, Yi-Ta
;
Yi, Chih-Wei
;
Lu, Yin-Chih
;
Tsai, Pei-Chuan
;
資訊工程學系
We propose the i-Traffic system that utilizes crowdsourced data from smartphones for the traffic flow mining by shockwave techniques. Shockwave is the propagation phenomenon of vehicle accumulation or relief on roads between two traffic flows with different speeds. The movement data of vehicles in front of an intersection are collected via smartphones for the shockwave identification. To conquer the low penetration problem when the number of the movement data is low, a folding heuristic is proposed by using traffic light cycle information to virtually increase the penetration of movement data. We implement our system on a client-server architecture and perform a small scale field trial experiment to demonstrate the system capability. Our results showed that our system is able to compute traffic information, including red/green light transition information and vehicle arrival rate with mean absolute errors of 5.0/0.6 seconds and 2.43 vehicles per minute, respectively under a low penetration rate of 1.2%.
Model the Vibrations of Rack-mounted On-vehicle Devices by Underdamped Oscillations
(2014-01-01)
Chuang, Yi-Ta
;
Yi, Chih-Wei
;
Wu, Tsung-Hsiang
;
Chan, Ching-Yao
;
資訊工程學系
Recently, rack-mounted devices such as smartphones were proposed to be installed on vehicles as the sensing source to detect road surface conditions by measuring the vibrations of the vehicles. However, due to lack of models, most proposed solutions need individual sensing system tuning or training based on extensive experiments to capture overall system characteristics and usually the outcomes can\'t be applied to other systems due to various factors, e.g., the suspension systems of vehicles, the mounting racks or adhering methods, the weight of the onboard device, and even the position on the vehicle. It becomes an obstacle for pervasive deployment of such systems. In this work, we intend to verify the feasibility of modeling vibrations measured by onboard devices by under-damped oscillation model (UOM) through time and frequency domain analyses. If the vibrations of the phone can be modeled by UOM, the measurement uncertainties caused by various factors that affect the sensed vibrations may potentially be eliminated. The vibrations caused by road anomalies could be measured in a relative objective way by the ratio of the vibration caused by road anomalies and the background vibrations. Our experimental results suggest that it is acceptabl to model the vibrations of onboard devices by the UOM.
Personalized Smartphone Wearing Behavior Analysis
(2014-01-01)
Lin, Yen-Hsuan
;
Chuang, Yi-Ta
;
資訊工程學系
;
Department of Computer Science
Next generation smartphones have the ability to sense user contexts such as mobility, device wearing position, location, activity, emotion, health condition. Many apps utilize user contexts to provide innovative services, e.g., pedometer, advanced navigation and location based services. Two of the most important user contexts are mobility patterns (still and walk) and device wearing positions (hand, arm, chest, waist and thigh). We call these two user contexts "wearing behavior". In this paper, we propose a 3-stage framework to recognize smartphone wearing behaviors by utilizing sensor data from smartphones. The framework starts with data preprocessing to extract sensor features and generate ground truths. After the data preprocessing, a threshold based finite state machine utilizes the sensor features to determine whether the smartphone is attached or not. Finally, a decision tree model is built based on the ground truth to determine the wearing behaviors. The experiment results show that our approach can achieve 94 % accuracy in average.
QoS-aware roadside base station assisted routing in vehicular networks
(2009-12-01)
Huang, Chenn-Jung
;
Chuang, Yi-Ta
;
Chen, You-Jia
;
Yang, Dian-Xiu
;
Chen, I-Fan
The transmission technology for intelligent transportation systems can be typically classified into two categories, namely, road-to-vehicle communication (RVC) and inter-vehicle communication (IVC). RVCs perform the information communication service offer from road to vehicle whereas the IVCs perform the information communication through vehicles. This work proposes quality of service (QoS)-aware roadside base station assisted routing mechanisms to establish a routing path in IVC with the assistance of roadside base station. A link failure prevention mechanism is employed to effectively construct alternative routing path required by the volatile network topology in vehicular Ad hoc networks. Besides, a bandwidth consumption predictor is presented to avoid dropping packets owing to inadequate bandwidth during handoffs. A neural network with fast learning algorithm is adopted as the core module for estimating the parameters used in the proposed schemes. Simulation results demonstrate the effectiveness and feasibility of the proposed work. (C) 2009 Elsevier Ltd. All rights reserved.
Shockwave Models for Crowdsourcing-based Traffic Information Mining
(2013)
Chuang, Yi-Ta
;
Yi, Chih-Wei
;
資訊工程學系
;
Department of Computer Science
Crowdsourcing is a new trend for pervasively discovering traffic information due to its low deployment and maintenance cost as compared with traditional infrastructure-based approaches, e. g., loop detectors and CCTV. Mining techniques and the penetration rate of participators in the discovery process are two major issues in such approaches. In this work, we first point out the shockwave phenomenon occurring in signalized traffic can be used to discover useful traffic information including traffic light information and vehicle flow information. To reduce the requirement on the penetration rate, a folding heuristic is proposed. The proposed concepts are verified via extensive simulations, especially on the penetration rate issue. Our results show that shockwave models are useful to extract traffic information from crowdsourced data, and the folding technique can effectively reduce the requirement on the penetration rate. It is remarkable that the proposed approach can provide high quality information even at a penetration rate as low as 1.6%.
Toward Crowdsourcing-Based Road Pavement Monitoring by Mobile Sensing Technologies
(2015-08-01)
Yi, Chih-Wei
;
Chuang, Yi-Ta
;
Nian, Chia-Sheng
;
資訊工程學系
;
Department of Computer Science
In crowdsourcing applications, the quality of the crowdsourced data is decisive to the success of subsequent system-level mining processes. We proposed a smartphone probe car (SPC) system to monitor road pavement. An SPC is essentially an ordinary vehicle with a mounted smartphone that runs sensing programs to objectively assess bumping caused by road anomalies such as potholes and bumps. The proposed system has several features. First, to allow dynamic forming of SPCs, we develop a signal processing heuristic for the extraction of the vertical acceleration components from the accelerometer readings (upon which bumping detection and road surface anomaly assessment rely). By these means, the proposed system provides a driver-friendly environment, requiring neither complicated installation nor driverassisted training processes, and thus is possible to achieve hassle-free mass deployment such that drivers would be willing to participate in crowdsourcing. Second, based on the underdamped oscillation model, we propose a road anomaly indexing heuristic that is representable for road anomalies rather than vehicle conditions. This will later facilitate the system-level data mining processes in the servers. Third, a prototype SPC system was implemented and extensive field tests were undertaken to verify the performance of our system framework. Furthermore, we experimentally adopted a DENCLUE-like algorithm to mine road anomaly information from reported events to demonstrate any potential benefit from future investigation of data mining process at the system level. We believe the research works introduced in this paper consist the first step toward building an "ecosystem" of SPC-based crowdsourcing traffic and road monitoring applications.
Using Learning Style-Based Diagnosis Tool to Enhance Collaborative Learning in an Undergraduate Engineering Curriculum
(2011-12-01)
Huang, Chenn-Jung
;
Liao, Jia-Jian
;
Shen, Hung-Yen
;
Aye, Nwe Ni
;
Wang, Yu-Wu
In this study, an intelligent learning style aware diagnosis agent for computer-supported cooperative learning is proposed. Learners are first assigned to heterogeneous groups based on their learning styles questionnaire given right before the beginning of learning activities on the e-learning platform. The proposed diagnosis agent then scrutinizes each learner's learning portfolio on e-learning platform and automatically issues feedback messages in case some learner's behavior that is unfitted to his/her learning styles or devious argument on discussion board or wiki is detected. The Moodle, an open-source software e-learning platform, is used to establish the cooperative learning environment for this study. The experimental results reveal that the proposed learning style aware diagnosis agent indeed boosts the performance of the learners. (C) 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 739-746, 2011; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.20359
XOR-Forwarding for Wireless Networks
(2009)
Wang, Hsiang-Po
;
Chuang, Yi-Ta
;
Yi, Chih-Wei
;
Tseng, Yu-Chee
;
Liu, Pin-Chuan
In this paper, we propose a localized network-coding-based packet forwarding protocol for wireless networks, called Opportunistic ASynchronous Information diSsemination (OASIS), based on COPE. OASIS not only inherents two features from COPE, opportunistic listening and opportunistic coding, but also introduces a new one, opportunistic information dissemination, which aggressively encodes as many packets as possible even if packets are not going to be received by their next hops. In addition, we point out that packet pool managements and packet information exchanges are critical in the implementation. Simulation results show that OASIS has network throughput about 1.4 times of traditional unicast forwarding, and the improvement is about 1.2 times of the improvement achieved by COPE.