Sung-Hyun Yang

Development of an Edge-Based Algorithm for Moving-Object Detection Using Background Modeling

Edges are a robust feature for object detection. In this paper, we present an edge-based background modeling method for the detection of moving objects. The edges in the image frames were mapped using robust Canny edge detector. Two edge maps were created and combined to calculate the ultimate moving-edge map. By selecting all the edge pixels of the current frame above the defined threshold of the ultimate moving edges, a temporary background-edge map was created. If the frequencies of the temporary background edge pixels for several frames were above the threshold, then those edge pixels were treated as background edge pixels. We conducted a performance comparison with previous works. The existing edge-based moving-object detection algorithms pose some difficulty due to the changes in background motion, object shape, illumination variation, and noises. The result of the performance evaluation shows that the proposed algorithm can detect moving objects efficiently in real-world scenarios.

Enhanced Loop Structure of NFC Antenna for Mobile Handset Applications

A new structure of an NFC loop antenna for mobile handset applications is proposed. The proposed antenna consists of conventional loop elements and a parasitic loop embedded capacitor to enhance its performance. Although the sintered ferrite sheets with higher relative permeability have been used to reduce the performance deterioration due to the eddy current on the battery pack of a mobile handset, their costs are high, and they are considerably breakable. In this paper, with the proposed structure, we effectively enhance the performance of an NFC loop antenna by employing the ferrite-polymer composite with lower relative permeability .

Two-layer hidden Markov model for human activity recognition in home environments

Activities of Daily Livings (ADLs) refer to the activities that are carried out by an individual for everyday living. Recognition of ADLs is key element for building intelligent and pervasive environments. We propose a two-layer HMM to build a ADLs recognition model that can represent the mapping between low-level sensor data and high-level activity based on the binary sensor data. We used embedded sensor with appliances or object to get object used sequence data as well as object name, type, interaction time, and location. In the first layer, we use location data of object used sensor to predict the activity class and in the second layer object used sequence data to determine the exact activity. We perform comparison with other activity recognition models using three real datasets to validate the proposed model. The results show that the proposed model achieves significantly better recognition performance than other models.

PARE: Profile-Applied Reasoning Engine for Context-Aware System

Context reasoning is an important issue for a context-aware system. Generally, context reasoning is adopted to deduce new context based on the available contexts. The rule-based reasoning is one of the most well-known methods for context reasoning. However, it is difficult for the rule-based algorithm to reason personalized context, because it requires a large number of rules to apply the users preferences. To address this weakness, in this paper we suggest the Profile-Applied Reasoning Engine (PARE). PARE is an enhanced rule-based reasoning method which uses profiles while reasoning contexts. By using profiles, PARE can become aware of the context that is preferred by a specific individual. To validate the effectiveness of the proposed reasoning engine, we compared the reasoning result of PARE with traditional rule-based reasoning in smart home domain. PARE shows better outcome for reasoning the personalized contexts than the traditional rule-based reasoning. In addition, by using profiles, a significant number of rules have been omitted and consequently the running time is also decreased. Moreover, PARE occupies less memory space which is restricted with number of variables of a rule. Therefore, PARE optimizes both runtime and memory space, which is valuable when making embedded context-aware system.

An Approach to Mitigating Sybil Attack in Wireless Networks using ZigBee

Various sensors employing ZigBee protocol send environment information to a home gateway. The home gateway manages every devices, sensors and services according to the information. However, if an attacker fabricates the information with malevolent purpose, the system may perform any inadvertent service, which may be harmful to users. Sybil attack is one of serious threats that uses such vulnerability. In this paper, we propose a Sybil attack detection method and its response method to mitigate the effect of the attack in wireless network using ZigBee. The proposed method employs a challenge-response approach. A verifier send a node a request that corresponds to an identity, and the receiver should respond the request properly within threshold time. The performance of the proposed method is reasonable for applying it to the practical networks. This will help the wireless networks using ZigBee to enhance its security.

Mathematical modelling of a context-aware system based on Boolean control networks for smart home

In this paper, we have presented a mathematical modelling of a context-aware system used in smart home based on Boolean control networks. This modelling describes the relationship between the context elements and services, which is effective to logical inference.

Mathematical Modeling of Smart Space for Context-Aware System: Linear Algebraic Representation of State-Space Method Based Approach

A smart space is embedded with several components such as sensors, actuators, and computing devices that enable the sensing and control of the environment, and the inhabitants interact with the devices in the smart space whenever they need to. To model a smart space, a dynamic relationship needs to be established among the elements of the space whereby the interactions with devices are considered a dynamic-process state. In this paper, a linear model of a smart space is presented using a state equation, where the two coefficient matrices and need to be defined to model the smart space, and the coefficient matrix is used to determine the states of the devices; similarly, the situation of the smart space is determined using coefficient . An algorithm is presented to make a linear model from the logical functions that are used to describe the system. This model is flexible in terms of the control of the smart-space environment because the environmental factors are represented by a matrix element. This linear smart-space model is helpful for the control of a context-aware system, and we use an example to illustrate the effectiveness of the proposed model.

Middleware aided context-aware service for smart home

To realize smart home services, several context-aware applications should be deployed which adapt their behavior depend on context information of home occupants. For context-aware service, context providing, processing, reasoning, delivery and designing context-aware applications are complex tasks. In this paper, we present a context-aware middleware which provides above tasks and supports context sharing in cooperative manner. We model domain context using ontology and adopt FOL which helps the context reasoning.

A New TR-UWB Receiver Exploiting Frequency Components

This letter presents a new TR-UWB receiver exploiting frequency components of UWB pulses. This is accomplished by separating frequency-components of UWB pulses into real and imaginary parts, independently correlating and effectively combining them. We analytically show this scheme improves the output SNR compared with a conventional one using complex correlation. This will also be justified by simulation results.

A POI-Based RFID Reader Deployment and Associated Interference Effect

This paper presents a simulation based method to predict the amount of frequency interference in a passive type RFID system. To judge occurrence of frequency interference, we use a parameter POI (probability of interference) that depends on several factors such as multiple access method, emission mask, the number of channel, etc. Due to its dependence on several factors, a Monte-carlo based simulation is suitably used. Through the simulation, we draw minimum separation distance between two readers and examine performance degradation due to aggregate interfering readers. Moreover, we present a reader deployment strategy based on the average POI of active readers operating in some area.