Earticle

We propose a moving target tracking algorithm using the measurement signals of time difference of arrival (TDOA) and the frequency difference of arrival (FDOA) in this paper. The geolocation system using TDOA measurement does not have enough accuracy to estimate the position of target. We use both TDOA and FDOA measurement signals to estimate the target location and target’s velocity at discrete times. The Kalman filter performs remarkably in calculation and location estimation. However, the estimation error can be large when the priori noise covariances are assumed with improper values. Therefore, we offer an adaptive extended Kalman filter (AEKF) to update the noise covariance at every measurement and estimation process to find proper noise covariance at each steps. The simulation results show our proposed algorithm reduces the position error effectively and improves the accuracy of target tracking greatly.

Multipath is one of the main error sources that influence GNSS precise relative positioning. To mitigate multipath error, this paper starts from study of variation characteristics of signal-to-noise ratio (SNR) measurements, and then proposes a satellite selection method based on SNR fluctuation for static relative positioning. Test results indicate that positioning accuracy can be significantly improved by the proposed method.

For a real-time system, the system correctness depends not only on the correctness of the logical result of the computation but also on the result delivery time. Real-time Operating System (RTOS) is widely accepted in designing real-time systems. The real-time performance is achieved by using real-time mechanisms through data communication and synchronization of inter-task communication (ITC) between tasks. Therefore, benchmarking the response time of real-time mechanisms is a good measure to predict the performance of real-time systems. This paper aims to analyze the response characteristics of real-time mechanisms in kernel and user space for real-time embedded Linux: RTAI and Xenomai. The performance evaluations of real-time mechanisms depending on the changes of task periods and load are also conducted in kernel and user space. Test metrics are jitter of periodic tasks and response time of real-time mechanisms including semaphore, real-time FIFO, Mailbox and Message queue. The results are promising to estimate deterministic real-time task execution in implementing real-time systems using RTAI or Xenomai.

In this paper we propose a new bit plane-based watermarking approach. In the proposed technique, an image is embedded in the least significant bit (LSB) plane of the original image. The selection of bit planes is a crucial issue because the performance and file size is determined by the selected bit plane. We used ten LC dataset for the experiments. From the simulation results, it is obvious that the presented method is reliable for watermarking.

The purpose of this study was to investigate the relationships of lifestyle factors, including energy intake and expenditure, to body mass index in male office workers. A total of 84 male office workers voluntarily participated in the study, and the participants’ lifestyle factors, which included body fat indicators such as body mass index, percent body fat, waist circumference, and waist-to-hip ratio, were measured. They also answered questionnaires recording their daily dietary intakes and average daily walking and sedentary time. For group analysis, the subjects were classified into normal weight (n=30) or overweight (n=54) groups based on a BMI cut-off point of 23.0kg/m2. Energy intake results showed that the overweight groups had significantly higher values for volume of dinner (p=.001), fat intake (p<.001), and frequency of skipping breakfast (p=.020) than the normal weight group. In terms of energy consumption, the overweight group had significantly lower values for commute time (p<.001) and significantly higher values for working hours (p=.017) and sedentary work time (p<.001) than the normal weight group. Pearson correlation analysis showed that dinner intake (p=.007) and sedentary work time (p<.041) were significantly related to BMI in both groups. Multiple linear regression analysis showed that dinner intake and sedentary work time were two independent predictors of BMI in office workers who participated in this study. In conclusion, the current findings of the study suggest that adopting healthy dietary habits, including dieting and regular meal times, as well as increased physical activity and reduced sitting time should be promoted as key components of lifestyle intervention for the prevention of body fatness in office workers.

This paper presents a decoder with enable input. This decoder is developed using quantum-dot cellular automata (QCA). QCA opens a completely radical way of microelectronics development and a potential replacement of CMOS based electronics. It ensures highly compact circuits, faster processing speeds, low power consumption. The use of clock in QCA provides power gain which is an important feature and this feature is not available in CMOS electronics. The proposed decoding architecture is designed using 5-input majority gate to keep a regularity so easily extendable for 3:8 or 4:16 decoders and also easy to connect with other circuits.

General gait design for a walking robot has an assumption that the weight of a leg is negligible compared to that of body. Under the assumption, only the gravity center of the body is taken into consideration in the gait design since the total gravity center of whole robot coincides always with the gravity center of the body only. Roughly speaking, however, motion of a weighty leg has serious influence on stable walking of a quadruped robot in practical sense. In this paper, an impedance control for body sway motion is proposed to compensate the influence of a weighty leg on the total gravity center of the robot, so that the walking stability is secured in accordance with the pre-designed gait with consideration of the gravity center of the body only.

This paper presents a frequency monitoring system for Korean wide-area power protection based on virtual FDR. The virtual FDR is introduced to enhance the simulation capability of frequency monitoring systems and consists of three parts: modeling, estimation, and simulation. Once a power grid model is obtained in the virtual FDR based on EMTP-RV, the frequency is estimated by DFT filtering and gain compensation based on real and imaginary filtering. Various disturbances and conditions are simulated using the data from the power grid model. The proposed FDR allows the monitoring system to display simulated disturbances and data, including voltages, currents, and frequencies. Various simulation results were given to show of the effectiveness of the proposed frequency monitoring system based on the virtual FDR.

The traditional approach to limiting the maximum output power of a FSAE car’s engine is to install a single circular restrictor at the engine. However, restrictor installation would adversely lower the air flow speed and fuel burning rate, which further result in the declining of the pressure in the intake pipe. In this paper, we first analyze the influence of intake restrictor on engine power, intake pipe’s pressure, inflatable efficiency and fuel consumption in the case of a typical four-stroke engine of FSAE cars. One-dimensional engine cycles are simulated by using the AVL BOOST. Intake quantity correction is then designed based on the characteristics of EFI system and the analysis results. The control unit is further designed by both means of hardware circuit and software design. According to pulse width of driving signal for injecting fuel, the performance of FSAE car’s engine is improved by intake quantity correction of the control unit. Other direct improvement includes lowered fuel consumption hence more economical efficiency.