Earticle

This article presents a new structure for solving global positioning system (GPS) outages for long periods without requiring any prior information about the characteristics of the inertial navigation system (INS) and GPS. Kalman filter (KF) is widely used in INS and GPS integration to present a forceful navigation solution by overcoming the GPS outage problems. However, KF is usually criticized for working under predefined models and for its observability problem of hidden state variables, sensor dependency, and linearization dependency. Therefore, this article proposes a dynamic adaptive neuro-fuzzy inference system (DANFIS) to predict the INS error during GPS outages based on the current and previous raw INS data. The proposed integrated system is evaluated using a real field test data. The performance of the proposed technique is also compared with the traditional artificial intelligence (AI) technique and KF. The results showed great improvements in positioning and especially in velocity for MEMS grade IMU and for different length of GPS outages.

In this paper, a nonlinear hybrid position/force control is designed for a constrained two degrees of freedom robot. System dynamics is formulated based on Lagrange-Euler approach. Our objective is to control separately the movement of the robot and its contact forces. The contact force is obtained via the inverse dynamics with dynamic frictional force. Force control is realized through a virtual desired position of the end effector. Simulation results give satisfactory outcomes and proof the efficiency of the proposed hybrid control concept.

In recent years, there has been increasing trend for multimedia applications to use delegate service providers for content distributions. These delegate services have brought new challenges to the protection of multimedia content confidentiality. Encryption can be used to hide information from unauthorized individuals, either in transit or in storage. This technique transforms the content into unintelligible and unviewable format. This paper proposes image encryption using secret sharing scheme. According to this process there are two levels of encryption. The first level, generates the random polynomial of degree (t-1) , where t is a threshold value. The constant term is taken as the secret. In the second level construct the transformation matrix using secret and primitive root theorem. This matrix is used for encryption purpose. Experimental results and security analysis shows that the proposed algorithm offers good resistance against brute force attack and statistical crypt analysis.

Navigation in mobile robot not only avoid obstacles based on the sensor input but also comprehend the nature of its environment, remember over time such comprehended scenarios, recollect them and associate in time perceptions of environment that resemble each other. Such requirements demand spatial and temporal reasoning capabilities, for considering the mobile robot environmental as an experience of a sequence of sensor patterns. Memory-based reasoning must integrate into mobile robot control strategy to produces efficiently movement in unpredictable environment, to achieve robustly and to reduce computational cost. To implement this strategy Fuzzy-Kohonen Network (FKN) technique is utilized by employing small number of rules. The effectiveness of the proposed technique is demonstrated in series of practical test on our experimental mobile robot in structured and unstructured environment. A detailed comparison of the proposed technique with other recent approaches in the specific case of ‘local minima’ detection and obstacle avoidance is also presented. As results found that mobile robot based on FKN technique has the ability to perform navigation tasks in several environments, it has capability to recognize the environment, suitable for low cost mobile robot due to only produce small resources, provides much faster response to expected events and it allows the mobile robot move without any need to stop for ‘danger’ situation without suffering from the ‘local minima’ problem.

This paper deals with the determination of the optimal state observer gain matrix for discrete-time linear systems. In this way, it has been shown that an improved optimal gain is reached by minimizing a quadratic criterion formulated as a quadratic output feedback control of the observation error system. The gradient matrix operation is applied to the Lagrangian function in order to obtain necessary conditions, for minimizing the proposed criterion, to perform the optimal gain matrix. It has been shown, by Lyapunov stability theory, that this optimal gain ensures the asymptotic convergence of the observation error towards zero. The necessary and sufficient conditions are presented by coupled discrete Lyapunov equations which resolution, by a proposed numerical algorithm, allows the calculus of the optimal observation gain. The importance of the proposed criterion for the synthesis of the state observer has been illustrated through numerical simulation study of the state observation of a robot with flexible link which has highlighted the effectiveness of the developed method in relation to that optimizing the dual system.

This paper proposes a class of General Piecewise-Affine (GPWA) AutoRegressive eXogenous (GPWARX) models for nonlinear black-box identification. A GPWARX model is a weighted sum of GPWA basis functions. In n-dimensions, a GPWA basis function is defined over n+2 polyhedral regions, which are pairwise directly adjacent in the domain space. The geometrical structures of GPWA basis functions provide the GPWARX models with stronger representation capability and higher approximation efficiency in estimation of nonlinear systems than the other canonical PWA functions. Benchmark nonlinear identification examples are illustrated to show that GPWARX models have better estimation accuracy than HHARX and BPWARX models with the same number of parameters and using the same parameter identification algorithm.

This paper focused on the design and implementation of a sliding mode controller with fuzzy logic tuning for depth control of an autonomous underwater vehicle (AUV). A fuzzy tuning approach to sliding mode control is employed for enhancing the tracking performance as well as reducing reaching time. The sliding surface can rotate or shift in the phase space in such a direction that the tracking behavior can be improved, which can be carried out using fuzzy tuning method. The reaching time and tracking error in the approaching phase can be significantly reduced. Experimental results indicate the effectiveness of the proposed controller in dealing with model uncertainties, nonlinearities of the vehicle dynamics and environmental disturbances caused by ocean currents and waves.

In this research the behavior of small-scaled wind turbine system is evaluated against strong wind input considering round trip delay. Generally, the wind turbine system is generating energy from the revolution of blades. The revolution of blades is depended on the velocity of wind. Therefore, if there is strong wind then the revolution of blade is increased and more energy will generated. Therefore, according to this situation the wind turbine systems are located in gale area in order to generate energy efficiency. However, there are specific limits of the revolution of blades or the angular velocity of blades. If the angular velocity exceeds the limit then wind turbine system may breakdown. Also, in this research time-delay element is considered due to the distance observation of behavior of system. Time-delay occur during the transposition of data between the observer and plant. Therefore, in this occasion round trip delay occurs in system. Hence, the closed loop of system may become unstable due to existence of time-delay element. Thus in this paper, in order to avoid the malfunction of wind turbine system and instability due to storm and time-delay element, respectively, restrained control is suggested. Restrained control is consist of pitch angle and axis friction control. The proposed method is to evaluate the restrained control with setting the reference angular velocity from low to high speed and different value of spring and damper. As consequences, for high speed reference signal and the restrained control contains better performance with strong damper.

In the grinding operation dressing sequence give proper profile and surface dimensions. Dressing eliminates loaded part in the wheel surface and makes wheel edge sharpening. Also specific surface profile in the dressing unit conveys to the material, and this is the main function with the dressing process. In this study precise and high-speed bearing steel grinding process are established as well as dressing conditions. In the dressing unit improving study slot type dresser unit showed less grinding power than non-slot type. Surface roughness is higher in the slot type dresser equipped conditions.

In this paper, we proposed the adaptive electronic acupuncture system in which patients’ biometric information is collected and patients’ condition is found automatically and then, patients are treated by their condition. In the proposed system, the electronic acupuncture with built in multi pad is used to relieve the pain that patients feel when they get acupuncture. We calculated the exact time of electronic acupuncture optimal for patients’ physical condition using fuzzy rules. By calculating the exact time, the patients can be treated with optimally, and acupuncture time can be shortened and strength of acupuncture can be moderated considering their condition. And also this system is safe for the infection by acupuncture and do not leave acupuncture injection mark. This system is useful for remote medical examination and treatment.

A tri-axial HTS power cable has been proposed and developed to reduce the number of HTS wires because it has copper shield instead of HTS shield. However, it has a drawback which is an inherent imbalance problem due to an asymmetry configuration in the cable. The authors designed a 22.9 kV/50 MVA class tri-axial HTS cable. The inherent imbalance problem of the three-phase currents in the tri-axial HTS power cable has been minimized through the adjustment of pitches and radii of each layer. An FEM analysis program and a power system analysis program were used to analyze the characteristics of the designed tri-axial HTS power cable. The AC loss and magnetic characteristics of the designed cable were analyzed according to magnitude of operating currents. The design results of the tri-axial HTS power cable are discussed in detail.

Compared to a typical one-way multi-lane highway, a one-way divided highway operated, for instance, in the form of two two-lanes instead of four lanes may have an advantage on safety more than operation. In congested traffic conditions, drivers would change lanes into less heavy lanes. Frequent lane changes cause unstable traffic flows, reduce capacity and increase accident possibility. The purpose of this study is to observe an impact of one-way divided highway scheme on traffic operation compared to the conventional undivided. Average travel time and travel time variance are observed for traffic operation performance and travel time variability in the environment of computer simulation. In results, an undivided highway showed better performance than a divided highway in all cases. For travel time variability, no significant difference between an undivided highway and a divided highway was with small on-ramp demands. The large inflow from on-ramps, however, increased more travel time variability in a divided highway system.

In this paper, we propose the remote control station in order to guarantee and increase the efficiency of combat abilities using unmanned ground vehicle (UGV). Our remote control station is capable of sending a variety of messages designed for carrying out the skillful movement for collaboration among UGVs. Also, we present the core components of unmanned ground vehicles to efficiently carry out the sophisticated and primary missions provided by remote control station in future combat field. The proposed UGV is consisted of many sophisticated-designed systems such as navigation, obstacle detection sensor, wheel activator for vehicle control and network devices for communication. The developed system, named UGV and remote control station, is easy to operate and enable significant reduction in station operator workload by utilizing an intuitive graphic user interfaces for UGV navigation and allowing a single station operator to command multiple UGVs simultaneously. To verity the effectiveness of our proposed system, we conduct a great many remote operating tests in the real environment. In the consequence of the operation test, we expect that the remote control station and UGV play an important role in the future military operation.

Recently, XML is widely used as the de facto standard for data representation and exchanging in Internet. In 2006, office application groups such as OpenOffice.org and Microsoft office both adopted XML as the main data storage format. Historical XML documents often have tiny differences between versions, but are stored individual independent space, so the abilities for efficient storing historical office documents are become a growing issue. This paper introduces an efficient way to decompose multi-version XML documents and store effectively for advanced retrieving. Not only effective storage space but also keeping the integral of original documents is the characteristic of our research. It minimizes the change of data content and structures when transmute historical XML documents. For enterprises, the approaches of our research can manage electronic documents in proper way and all messages in document were preserved to reuse.

Scalable video coding (SVC) is an extension of H.264/MPEG 4 AVC approved by JVT on November, 2007. The characteristic of the SVC is the encoding of a high-quality video bitstream that contains one or more enhancement layer bitstreams in addition to the base layer bitstream. We propose a fast enhancement layer macro block (MB) mode decision algorithm for spatial scalable SVC utilizing statistical characteristics of lower layer. The MB mode of spatial enhancement layer is statistically highly correlated with MB mode of lower layer. The proposed algorithm intelligently limits the possible candidate MB modes of enhancement layer to the modes predicted from the base layer for spatial scalable coding. We implemented our algorithm on JSVM codec to verify the performance of our algorithm. Using our algorithm, we can reduce the encoding time while almost maintaining PSNR and bitrate.

Refer to this research, a linear error-based tuning sliding mode controller (LTSMC) is proposed for robot manipulator. Sliding mode controller (SMC) is an important nonlinear controller in a partly uncertain dynamic system’s parameters. Sliding mode controller has difficulty in handling unstructured model uncertainties. It is possible to solve this problem by combining sliding mode controller and adaption law which this method can helps improve the system’s tracking performance by online tuning method. Since the sliding surface gain ( ) is adjusted by new linear tuning method, it is continuous. In this research new is obtained by the previous multiple sliding surface slopes updating factor which is a coefficient varies between half to one. Linear error-based tuning sliding mode controller is stable model-based controller which eliminates the chattering phenomenon without to use the boundary layer saturation function. Lyapunov stability is proved in linear error-based tuning sliding mode controller based on switching (sign) function. This controller has acceptable performance in presence of uncertainty (e.g., overshoot=0%, rise time=0.4 second, steady state error = 1.8e-10 and RMS error=1.16e-12).

This study was focused on the theoretical modeling and numerical simulation about the speed and temperature field of metal drop in high-melting metal arc spraying. The influences of the metal drop speed and temperature field in high-speed flight temperature distribution cloud chart and different air pressures on grain’s flying speed were investigated. The result showed that, the highest speed of jet flow at the outlet of the spray gun reaches 600m/s; the air velocity quickly reduces to subsonic velocity after ejection within the spraying distance of 0-250mm . The air velocity continuously reduces along with the spraying distance increases. It is found that the grain’s flying speed increases along with air pressure increase with the biggest speed within 200-250m/s and the grain’s accelerated speed increases along with increase of air pressure and airflow speed when the spray gun structure is unchanged. Grain diameter has obvious influence on jet flow grain’s flying speed.

IPTV is convergence broadcasting and communication. Mobile devices used wireless network such as Smart Phone, Lap-top, PDA and etc. These days, IPTV and mobile devices users increased drastically and together with this, the technology development increases as well. Mobile IPTV technology issues to address enabling IPTV services to be efficiently applied on mobile devices. Handover mean is moving mobile device to other base station from present base station. Handover most happened in Mobile network. When performing handover, there is a long handover delay in standard Mobile IPv6. So, Standard MIPv6 has many problems such as Packet loss, out-of sequence and etc. In other words, wireless network should solve many problems to provide Service of good quality. In this paper, we proposed Handover scheme over standard Mobile IPv6. It can provide Service of good quality to users. Mobile IPTV technology issues to address enabling IPTV services to be efficiently applied on mobile devices.

Based on a theoretical erbium-doped fiber amplifier (EDFA) model, we have proposed a systematic design method for EDFA gain control. In the design, a disturbance observer(DOB) technique is adopted for minimizing gain-transient time of wavelength-division-multiplexing (WDM) multi channels in optical amplifier in channel add/drop networks. We have reduced the gain-transient time to less than 30μsec by applying DOB with PID controller to the control of amplifier gain. The proposed DOB-based gain control algorithm for EDFA was implemented as a digital control system using TI's DSP(TMS320C28346) chip and experimental results of the system verify the excellent performance of the proposed gain control methodology.

There are two kinds of public address (PA) systems: analog PA systems and digital PA systems. The digital PA systems have better communication quality than analog PA systems, and many companies manufacture various types of digital PA systems. Digital PA systems are used in public places where there are vast crowds of people. In this paper, a digital, minimized, and integrated PA system was developed. Its facilities included an external input, a microphone, a CD, and a radio for a PA system. The developed digital integrated PA system with an operational MICOM will make it possible to centrally control digital device facilities. The operational MICOM has three layers: a control layer, a processing layer, and a user interface layer. In addition that, the remote control and key inputs are used for the central control. The execution results showed that the system can operate different digital media individually or together concurrently.

Implemented a small scale laboratory based Thyristor switched capacitor - thyristor controlled reactor (TSC-TCR) type static var compensator (SVC). The automatic control circuit has been implemented using microcontroller and tested with the Single Machine Two Bus Test system (SMTB) without and with SVC. Experimental results are presented and P-V Curves have been drawn for both the cases. Automatic control circuit have been designed and fabricated using LPC 2148 Microcontroller. The same test system was tested with SVC automatic control circuit and experimental results have been presented in this paper. The P-V Curves of the SMTB Test system with and with out SVC have been plotted which shows the effectiveness of SVC on Voltage Stability improvement.

The internal grinding process has precise and narrow tolerance areas in both its size and form-shaping aspects. In the conventional grinding process, which grinds normal tempered hardened steel, aluminum oxide is predominantly used as a grinding wheel material. This has the advantage of self-sharpening during the process. Together with this conventional material, CBN has emerged as a new substitution in steel grinding. In this study, grinding characteristics when using ceramic and CBN wheels for internal grinding were analyzed. Ceramic wheel cutting edge sharpness is much better than the CBN wheel, and in the CBN wheel case, initial wheel status causes glazing and loading which slightly increase grinding power.