Position based key exchange:definitions and implementations

Chandran,et al.introduce the direction of position based cryptography at CRYPTO 2009.In position based cryptography,the position of a party is used to be its unique“credential”in order to realize the cryptographic tasks,such as position based encryption,position based signature,position based key exchange and so on.Position based key exchange,as a basic primitive in position based cryptography,can be used to establish a shared key based on the position of the participant.To begin with,this paper presents the notions of the prover-to-verifier mode and the prover-to-prover mode for position based key exchange.In the prover-to-verifier mode,a secret key can be shared between a prover and the verifiers according to the position of the prover.While in the prover-to-prover mode,two provers located at the valid positions can negotiate a shared key with the help of the verifiers and any other party whose position is illegal cannot obtain the shared key.At the same time,this paper formalizes two security definitions against colluding adversaries:position based prover-to-verifier key exchange and position based prover-to-prover key exchange.Then,this paper introduces the bounded retrieval model and the implementations of position based key exchange in two modes based on the bounded retrieval model.Finally,this paper discusses the position based key exchange protocols in two modes from both security and performance perspectives.

MagneFi: Multiuser, Multi-Building and Multi-Floor Geomagnetic Field Dataset for Indoor Positioning

Indoor positioning and localization have emerged as a potential research area during the last few years owing to the wide proliferation of smartphones and the inception of location-attached services for the consumer industry.Due to the importance of precise location information,several positioning technologies are adopted such as Wi-Fi,ultrawideband,infrared,radio frequency identification,Bluetooth beacons,pedestrian dead reckoning,and magnetic field,etc.Although Wi-Fi and magnetic field-based positioning are more attractive concerning the deployment of Wi-Fi access points and ubiquity of magnetic field data,the latter is preferred as it does not require any additional infrastructure as other approaches do.Despite the advantages of magnetic field positioning,comparing the performance of positioning and localization algorithms is very difficult due to the lack of good public datasets that cover various aspects of the magnetic field data.Available datasets do not provide the data to analyze the impact of device heterogeneity,user heights,and time-specific magnetic field mutation.Moreover,multi-floor and multibuilding data are available for the evaluation of state-of-the-art approaches.To overcome the above-mentioned issues,this study presents multi-user,multidevice,multi-building magnetic field data which is collected over a longer period.The dataset contains the data from five different smartphones including Samsung Galaxy S8,S9,A8,LG G6,and LG G7 for three geographically separated buildings.Three users including one female and two males collected the data for various path geometry and data collection scenarios.Moreover,the data contains the magnetic field samples collected on stairs to test multifloor localization.Besides the magnetic field data,the data from inertial measurement unit sensors like the accelerometer,motion sensors,and barometer is provided as well.

The Study of Group Scheduling Problems with General Dual-Position-Based Job Processing Times

Scheduling with group technology has been a vivid research area in the past decades.However,group technology with general dual-effect variable processing times needs to be further explored although this kind of group technology plays an important role in some actual manufacturing scenarios.Accordingly,this paper considers group scheduling problems with a kind of general group variable processing times model,where the actual processing time of each job in group is variable due to the dual effect of both the job position and the group position.The objectives of two types of considered problems are to minimize the makespan and the total completion time,respectively.Based on the decomposition analysis,the mathematical logic analysis and the computational complexity proof,it is obtained that the makespan minimization problem and the total completion time minimization problem are both polynomially solvable under the condition that the group number is constant.For three special cases of considered problems,polynomial solving algorithms with lower computational complexity are proposed.

A position sensor based on grating projection with spatial filtering and polarization modulation

A position sensor based on grating projection with spatial filtering and polarization modulation is presented. A grating is projected onto the object to be measured through a 4f optical system with a spatial filter. After reflected by the object, the grating projection is imaged on a detection grating through another 4f optical system to form moiré fringes, The polarization modulated moiré signal is detected to obtain the position information of the object. In the position sensor, the moiré signal varies sinusoidally with the position of object. The measurement is independent of the incident intensity on the projection grating and the reflectivity of the object to be measured, In experiments, the effectiveness of the position sensor is proved, and the root mean square （RMS） error at each measurement position is less than 13 nm.

Traffic Data： Bluetooth Sensors vs. Crowdsourcing——A Comparative Study to Calculate Travel Time Reliability in Calgary, Alberta, Canada

The City of Calgary did a comparative study between two techniques of traffic data collection： Bluetooth sensors and crowdsourcing, for measuring travel time reliability on two goods movement corridors in Calgary, Alberta. To estimate travel time and speed, we used the output of BIuFAX sensors, which were operated by monitoring Bluetooth signals at several points along a roadway. On the other hand, TomTom historical traffic data were extracted from the TomTom Traffic Stats portal. To calculate travel time reliability, we applied the buffer index, and the planning time index recommended by FHWA （Federal Highway Administration）. The Bluetooth traffic data were presumed as the benchmark in this study. Unlike the TomTom traffic data, the data provided by the Bluetooth technology met the minimum recommended sample size requirement, although data processing was time consuming and impractical for long study periods. Our study results showed that crowdsourcing technique can be a viable alternative and provide travel time reliability estimates with a reasonable accuracy, when there are adequate numbers of records registered. However, the TomTom sample sizes in Calgary were not large enough to provide a statistically reliable method of providing travel time indices. Further researches may verify the accuracy of crowdsourcing technologies for travel time studies.

Performance of a New Ion Source for KSTAR Tokamak Plasma Heating

In the experimental campaign of 2010 and 2011 on KSTAR, the NBI-1 system was equipped with one prototype ion source and operated successfully, providing a neutral beam power of 0.7-1.6 MW to the tokamak plasma. The new ion source planned for the 2012 KSTAR campaign had a much more advanced performance compared with the previous one. The target performance of the new ion source was to provide a neutral deuterium beam of 2 MW to the tokamak plasma. The ion source was newly designed, fabricated, and assembled in 2011. The new ion source was then conditioned up to 64 A/100 keV over a 2-hour beam extraction and performance tested at the NB test stand （NBTS） at the Korea Atomic Energy Research Institute （KAERI） in 2012. The measured optimum perveance at which the beam divergence is a minimum was about 2.5μP, and the minimum beam divergent angle was under 1.0° at 60 keV. These results indicate that the 2.0 MW neutral beam power at 100 keV required for the heating of plasma in KSTAR can be delivered by the installation of the new ion source in the KSTAR NBI-1 system.

Base position planning of mobile manipulators for assembly tasks in construction environments

With good mobility and flexibility,mobile manipulators have shown broad applications in construction scenarios.Base position(BP)planning,which refers to the robot autonomously determining its working station in the environment,is an important technique for mobile manipulators when performing the construction assembly task,especially in a large-scale construction environment.However,the BP planning process is tedious and time-consuming for a human worker to carry out.Thus,to improve the efficiency of construction assembly tasks,a novel BP planning method is proposed in this paper,which can lead to appropriate BPs and minimize the number of BPs at the same time.Firstly,the feasible BP regions are generated based on the grid division and the variable workspace of the mobile manipulator.Then,the positioning uncertainties of the mobile manipulator are considered in calculating the preferred BP areas using clustering.Lastly,a set coverage optimization model is established to obtain the minimum number of BPs using an optimization algorithm according to the greedy principle.The simulated experiment based on a 9-degree of free(DoF)mobile manipulator has been performed.The results illustrated that the time for BP planning was significantly reduced and the number of BPs was reduced by 63.41%compared to existing manual planning,which demonstrated the effectiveness of the proposed method.

The Cell Modules of the Green Algebra of Drinfel'd Quantum Double D(H_(4))

This paper is devoted to studying the structures of the cell modules of the complexified Green algebra R(D(H_(4))),where D(H_(4))is the Drinfel'd quantum double of Sweedler's 4-dimensional Hopf algebra H_(4).We show that R(D(H_(4)))has one infinite dimensional cell module,one 4-dimensional cell module generated by all finite dimensional indecomposable projective modules of D(H_(4))and infinitely many 2-dimensional cell modules.More precisely,we obtain the decompositions of all finite dimensional cell modules into the direct sum of indecomposable submodules,and show that the infinite dimensional cell module can be written as the direct sum of two infinite dimensional indecomposable submodules.