Guaranteed cost control for networked control systems

The guaranteed cost control problem for networked control systems (NCSs) is addressed under communication constraints and varying sampling rate. First of all, a simple information-scheduling scheme is presented to describe the scheduling approach of system signals in NCSs. Then, based on such a scheme and given sampling method, the design procedure in dynamic output feedback manner is also derived which renders the closed loop system to be asymptotically stable and guarantees an upper bound of the LQ performance cost function.

Adaptive Resource Allocation Algorithm for Internet of Things with Bandwidth Constraint

In order to improve the transmission accuracy and efficiency of sensing and actuating signals in Internet of Things （loT） and ensure the system stability, an adaptive resource allocation algorithm is proposed, which dynami- cally assigns the network bandwidth and priority among components according to their signals＇ frequency domain characteristics. A remote sensed and controlled unmanned ground vehicle （UGV） path tracking test-bed was devel- oped and multiple UGV＇s tracking error signals were measured in the simulation for performance evaluation. Results show that with the same network bandwidth constraints, the proposed algorithm can reduce,, the accumulated and maximum errors of UGV path tracking by over 60% compared with the conventional static algorithm.

Strains Recorded Using a Seismometer Data Acquisition Unit

A seismometer data acquisition unit has been used in the Changping seismic station to record the output of a strainmeter. The output of a strainmeter was sampled at a rate of l00/sec by seismometer acquisition from the original rate of 1 per minute. Plenty of high frequency sampled data was recorded. The minute value curve calculated from the seismometer acquisition are consistent with that of the original data sampled by the strain acquisition system. More complete waveforms were recorded with a higher sampling rate, and seismic phase parameters calculated by using higher sampling rate strain seismic waves are also in consistency with the results of its predecessors. Spectra of the strain seismic waves are compared with that of seismic waves recorded by a seismometer in the Shisanling seismic station, and their trends are almost the same. Besides, some lower frequency components still exist in strain seismic waves.

Impact of environmental factors on the sampling rate ofβ-blockers and sulfonamides from water by a carbon nanotube-passive sampler

Passive techniques are a constantly evolving approach to the long-term monitoring of micropollutants,including pharmaceuticals,in the aquatic environment.This paper presents,for the first time,the calibration results of a new CNTs-PSDs(carbon nanotubes used as a sorbent in passive sampling devices)with an examination of the effect of donor phase salinity,water pH and the concentration of dissolved humic acids(DHAs),using both ultrapure and environmental waters.Sampling rates(R_(s))were determined for the developed kinetic samplers.It has been observed that the impact of the examined environmental factors on the R_(s) values strictly depends on the type of the analytes.In the case ofβ-blockers,the only environmental parameter affecting their uptake rate was the salinity of water.A certain relationship was noted,namely the higher the salt concentration in water,the lower the Rs values ofβ-blockers.In the case of sulfonamides,water salinity,water pH 7-9 and DHAs concentration decreased the uptake rate of these compounds by CNTs-PSDs.The determined Rs values differed in particular when the values obtained from the experiments carried out using ultrapure water and environmental waters were compared.The general conclusion is that the calibration of novel CNTs-PSDs should be carried out under physicochemical conditions of the aquatic phase that are similar to the environmental matrix.

The Statistical Relationship between the Maximum Amplitude of the Body Strain Record and the Surface-wave Magnitude and Epicenter Distance

Based on the body strain record of Tiantanghe station from 2008 to 2014,we make a statistical analysis of the relationship between the maximum amplitude of the body strain record and the surface-wave magnitude,epicenter distance of the earthquakes,which occurred in the Chinese mainland and its surrounding areas with MS≥6. 0 and the rest of the world with MS≥7. 0. According to statistical results,we propose a statistical formula between the surface-wave magnitude of earthquake and the maximum amplitude of the body strain record,the epicenter distance: M_S~*= 0. 37 ln A_max+ 0. 57 ln D + 0. 07. We can also derive a theoretical estimation formula for the maximum amplitude: A_max=e^(2. 7(M_S^*-0. 07))D^(-1. 54). This demonstrates that the maximum amplitude of the body strain record increases exponentially with the increase of the surface-wave magnitude, and decreases with the increase of the epicenter distance,and shows a negative correlation with their product. We further discuss the necessity of adding instruments with high frequency sampling to earthquake monitoring, and dicuss the prospects for precise earthquake prediction in future.

Analysis of noncommensurate sampling effects on the performance of PN code tracking loops

Noncoherent early-late processing （NELP） code tracking loops are often implemented using digital hardware for digital global positioning system （GPS） receivers. Noncommensurate sampling technology is widely used because it is viewed as an effective solution to cope with the drawback of digital effects. However, the relationship between the sampling rate and auto-correlation function （ACF） is not adequately characterized by traditional analysis. The principles for selecting the sampling rate are still not apparent. In order to solve this problem, we first analyzed the effects of different sampling rates on ACF and obtained the analytical form of a discrete auto-correlation function （DACF） for a noncommensurate sampling rate. Based on the result, the relationship between the step variation in DACF and NELP parameters such as sampling rate, integration time, and correlator spacing was determined. The maximum step variation size of DACF was also determined. However, considering the actual situation, additional factors such as code Doppler shift, precorrelation filter, and thermal noise may degrade the step variation of DACE The relationship between the step variation and these factors was analyzed separately. An appropriate sampling rate and appropriate correlator spacing were proposed to achieve the typical accuracy of measurement. The numerical simulation verified the validity of the above theoretical analyses, and finally, the conclusions and design constraints for the digital GPS receiver are summarized.

Impact of different sampling rates on precise point positioning performance using online processing service

In this study,the effect of different sampling rates(i.e.observation recording interval)on the Precise Point Positioning(PPP)solutions in terms of accuracy was investigated.For this purpose,a field test was carried out inÇorum province,Turkey,on 11 September 2019.Within this context,a Geodetic Point(GP)was established and precisely coordinated.A static GNSS measurement was occupied on the GP for about 4-hour time at 0.10 second(s)/10 Hz measurement intervals with the Trimble R10 geodetic grade GNSS receiver.The original observation file was converted to RINEX format and then decimated into the different data sampling rates as 0.2 s,0.5 s,1 s,5 s,10 s,30 s,60 s,and 120 s.All these RINEX observation files were submitted to the Canadian Spatial Reference System-Precise Point Positioning(CSRS-PPP)online processing service the day after the data collection date by choosing both static and kinematic processing options.In this way,PPP-derived static coordinates,and the kinematic coordinates of each measurement epoch were calculated.The PPP-derived coordinates obtained from each decimated sampling intervals were compared to known coordinates of the GP for northing,easting,2D position,and height components.According to the static and kinematic processing results,high data sampling rates did not change the PPP solutions in terms of accuracy when compared to the results obtained using lower sampling rates.The results of this study imply that it was not necessary to collect GNSS data with high-rate intervals for many surveying projects requiring cm-level accuracy.

Impact of Sampling Rate of IGS Satellite Clock on Precise Point Positioning

Both static and kinematic testings are investigated by using IGS 5rain, 30s and 5s-interval precise satellite clock prod- ucts in precise point positioning （PPP） solution. Test results show that the sampling rate oflGS satellite clock has very little effect on the static PPP solution. All the three types of sampling intervals of precise satellite clock can satisfy mm-cm level of positioning accuracy; higher sampling rate has no significant improvement for PPP solution. However, sampling rate of satellite clock has a significant impact on the PPP solution in kinematic PPP. The higher the interval of satellite clock, the better the accuracy achieved. The accuracy of kinematic PPP achieved by using 30s-interval precise satellite clock is improved by nearly 30-50 percent with re- spect to the solution by using 5min-interval precise satellite clock, but using 5s and 30s-interval satellite clock can almost produce the same accuracy of kinematic solution. Moreover, the use of precise satellite clock products from different analysis centers may also produce more or less effect on the PPP solution.

Error Rate Estimation in Quantum Key Distribution with Finite Resources

The goal of quantum key distribution(QKD) is to generate secret key shared between two distant players,Alice and Bob. We present the connection between sampling rate and erroneous judgment probability when estimating error rate with random sampling method, and propose a method to compute optimal sampling rate, which can maximize final secure key generation rate. These results can be applied to choose the optimal sampling rate and improve the performance of QKD system with finite resources.

Performance Improvement of Discrete-time Linear Control Systems Subject to Varying Sampling Rates Using the Tikhonov Regularization Method

Methods to stabilize discrete-time linear control systems subject to variable sampling rates,i.e.,using state feedback controllers,are well known in the literature.Several recent works address the use of the Tikhonov regularization method,originally designed to attenuate the noise effects on ill-posed problems,with the aim of improving performance and stabilizing approximately controllable dynamical systems.Inspired by these works,we propose the use of a feedback controller designed using the Tikhonov method to regularize discrete-time linear systems subject to varying sampling rates.The goal is to minimize an error function,thus improving the performance of the closed loop system and reducing the possibility of instability.Illustrative examples show the effectiveness of the proposed method.

On the Sum-Rate Capacity of Poisson Multiple Access Channel with Non-Perfect Photon-Counting Receiver

We investigate two-user sum-rate capacity for Poisson channel considering practical photon-counting receiver,including finite sampling rate and dead time.The sum-rate capacity reduction due to photon-counting loss is characterized and compared with that of continuous Poisson channel.We show that the sum-rate capacity with non-perfect receiver approaches the capacity of continuous time Poisson channel as the sampling time and dead time both approach zero.For optimal transmission strategy,we demonstrate three possible transmission strategies,including only one active user and two active users.In addition,we study the special case of identical peak power constraint for each user.We adopt majorization method to demonstrate that the optimal duty cycle for the two users must be the same and unique.Furthermore,we analyze the sum-rate capacity for multiple input single output(MISO)multiple-access channel(MAC).We propose a sufficient condition on dead time where the sum-rate capacity of the Poisson MISO-MAC is equivalent to that of single input single output,and the equivalence would not hold for sufficient large peak power or dead time.The theoretical capacity results are validated by numerical results.

Fractional Fourier domain analysis of decimation and interpolation

The sampling rate conversion is always used in order to decrease computational amount and storage load in a system. The fractional Fourier transform （FRFT） is a powerful tool for the analysis of nonstationary signals, especially, chirp-like signal. Thus, it has become an active area in the signal processing community, with many applications of radar, communication, electronic warfare, and information security. Therefore, it is necessary for us to generalize the theorem for Fourier domain analysis of decimation and interpolation. Firstly, this paper defines the digital frequency in the fractional Fourier domain （FRFD） through the sampling theorems with FRFT. Secondly, FRFD analysis of decimation and interpolation is proposed in this paper with digital frequency in FRFD followed by the studies of interpolation filter and decimation filter in FRFD. Using these results, FRFD analysis of the sampling rate conversion by a rational factor is illustrated. The noble identities of decimation and interpolation in FRFD are then deduced using previous results and the fractional convolution theorem. The proposed theorems in this study are the bases for the generalizations of the multirate signal processing in FRFD, which can advance the filter banks theorems in FRFD. Finally, the theorems introduced in this paper are validated by simulations.

Application of the DRS4 chip for GHz waveform digitizing circuits

A new fast waveform sampling digitizing circuit based on the domino ring sampler （DRS）, a switched capacitor array （SCA） chip, is presented in this paper, which is different from the traditional waveform digitizing circuit constructed with an analog to digital converter （ADC） or time to digital converter. A DRS4 chip is used as a core device in our circuit, which has a fast sampling rate up to five gigabit samples per second （GSPS）. Quite satisfactory results are acquired by the preliminary performance test for this circuit board. Eight channels can be provided by one board, which has a 1 V input dynamic range for each channel. The circuit linearity is better than 0.1%, the noise is less than 0.5 mV （root mean square, RMS）, and its time resolution is about 50 ps. Several boards can be cascaded to construct a multi-board system. The advantages of high resolution, low cost, low power dissipation, high channel density and small size make the circuit board useful not only for physics experiments, but also for other applications.

How much information is lost when sampling driving behavior data?Indicators to quantify the extent of information loss

Purpose–Individuals’driving behavior data are becoming available widely through Global Positioning System devices and on-board diagnostic systems.The incoming data can be sampled at rates ranging from one Hertz(or even lower)to hundreds of Hertz.Failing to capture substantial changes in vehicle movements over time by“undersampling”can cause loss of information and misinterpretations of the data,but“oversampling”can waste storage and processing resources.The purpose of this study is to empirically explore how micro-driving decisions to maintain speed,accelerate or decelerate,can be best captured,without substantial loss of information.Design/methodology/approach–This study creates a set of indicators to quantify the magnitude of information loss(MIL).Each indicator is calculated as a percentage to index the extent of information loss(EIL)in different situations.An overall information loss index named EIL is created to combine the MIL indicators.Data from a driving simulator study collected at 20 Hertz are analyzed(N=718,481 data points from 35,924 s of driving tests).The study quantifies the relationship between information loss indicators and sampling rates.Findings–The results show that marginally more information is lost as data are sampled down from 20 to 0.5 Hz,but the relationship is not linear.With four indicators of MILs,the overall EIL is 3.85 per cent for 1-Hz sampling rate driving behavior data.If sampling rates are higher than 2 Hz,all MILs are under 5 per cent for importation loss.Originality/value–This study contributes by developing a framework for quantifying the relationship between sampling rates,and information loss and depending on the objective of their study,researchers can choose the appropriate sampling rate necessary to get the right amount of accuracy.