Robot Operating System (ROS) controlled anthropomorphic robot hand

This paper presents a new design of a dexterous robot hand by incorporating human hand factors. The robotic hand is a Robot Operating System (ROS) controlled standalone unit that can perform key tasks and work independently. Hardware such as actuators, electronics, sensors, pulleys etc. are embedded within or on the hand itself. Raspberry Pi, a single board computer which runs ROS and is used to control the hand movements as well as process the sensor signals is placed outside of the hand. It supports peripheral devices such as screen display, keyboard and mouse. The hand prototype is designed in Solid Works and 3D printed/built using aluminum sheet. The prototype is similar to the human hand in terms of shape and possesses key functionalities and abilities of the human hand, especially to imitate key movements of the human hand and be as dexterous as possible whilst keeping a low cost. Other important factors considered while prototyping the model were that the hand should be reliable, have a durable construction, and should be built using widely available off-the-shelf components and an open-source software. Though the prototype hand only has 6 degrees-of-freedom (DOF) compared to the 22 DOF of the human hand, it is able to perform most grasps effectively. The proposed model will allow other researchers to build similar robotic hands and perform specialized research

Ab initio derivation of interatomic interactions in transition metals

An approach to the ab-initio calculation of many-body interatomic potentials in transition metals (TM) is developed. It is based on utilizing the local spin density approximation and linear superposition assumption for the density of the valence electrons. The analytic expressions for the spin dependent pair and triplet interatomic interactions are given. The many-body potentials for three particles and four particles are shown to be indirect and to describe interactions of the same spin orientation.Розвинуто оригінальний підхід обчислення багаточастинкових міжатомних потенціалів у перехідних металах. Він грунтується на використанні наближення локальної густини спінів та припущенні про те, що густину валентних електронів можна представити у вигляді лінійної суперпозиції. Подані явні вирази для парних та потрійних взаємодій, що залежать від орієнтації спіна. Показано, що багаточастинкові потенціали (три-, чотиричастинкові) описують опосередковані міжатомні взаємодії однакової орієнтації спінів

How does one extract many-body interatomic potentials from ab-initio band structure calculations

An original approach to the ab-initio deriving many-body interatomic potentials in metals is discussed. It is based on calculating the Kohn-Sham total energy functional using the pseudopotential method. The local density approximation (LDA) is shown to be applied, within the pseudopotential concept, to the analysis of the valence electron kinetic energy. Utilizing the LDA and linear superposition assumption for total electron density enables us to treat the exchange-correlation and kinetic energies of valence electrons in terms of contributions to indirect many-body interactions. Equations for the pair and for the triplet potentials in metals are given. Relationship between the method developed and other approaches is analyzed.Викладено підхід, в основі якого лежить використання методу псевдопотенціалів та формалізму Кона-Шема. Показано, як у наближенні локальної густини можна записати обмінно-кореляційну та кінетичну енергії валентних електронів у вигляді внесків у непрямі (опосередковані) багаточастинкові взаємодії. Аналізується зв’язок розвиненого підходу з відомим способом отримання міжатомних потенціалів у рамках теорії збурень за псевдопотенціалом. Подано явні вирази для парних і тричастинкових потенціалів

Wrist movement detector for ROS based control of the robotic hand

Robotic hands are used in a wide range of applications. They have many different shapes, constructions and capabilities. This work presents a new design of a robotic hand using tailor-made as well as widely available sensors and actuators. The information transferred between the sensor and actuators is processed using the Robot Operating System (ROS) topic mechanism. The robotic hand movement is remotely controlled by a movement detector mounted on the wrist of a human hand controller. Based on this simple hardware setup we demonstrate that the robotic hand can be remotely opened and closed thereby allowing to grasp objects flexibly

Observations of Six Glitches in PSR B1737-30

Six glitches have been recently observed in the rotational frequency of the young pulsar PSR B1737-30 (J1740-3015) using the 25-m Nanshan telescope of Urumqi Observatory. With a total of 20 glitches in 20 years, it is one of the most frequently glitching pulsars of the about 1750 known pulsars. Glitch amplitudes are very variable with fractional increases in rotation rate ranging from 10^{-9} to 10^{-6}. Inter-glitch intervals are also very variable, but no relationship is observed between interval and the size of the preceding glitch. There is a persistent increase in |\dot\nu|, opposite in sign to that expected from slowdown with a positive braking index, which may result from changes in the effective magnetic dipole moment of the star during the glitch.Comment: 7 pages, 10 figure

How does the estimated phase of menstrual cycle or menopause influence the prevalence of vasovagal syncope induced by head-up tilt test

Background: The purpose of this study was to evaluate the prevalence of syncope induced by head-up tilt test (HUTT) and the type of positive vasovagal response to the orthostatic stress in a relationship to the estimated phase of menstrual cycle (follicular phase, luteal phase) or menopause. Methods: We observed a cohort of 500 women at age 13–89 years (median of age 37.5), referred to HUTT. Phase of the menstrual cycle was determined on the basis of the usual length of menstrual cycle and the day of the cycle at the time of the study. We assumed that the length of the luteal phase is constant and it is 14 days. Results: In premenopausal patients, the occurrence of the mixed and cardioinhibitory response was significantly more frequent in comparison to postmenopausal women (48.8 vs. 35.1% and 19.7 vs. 12.4%, respectively; p < 0.00001), while the occurrence of the vasodepressive one was significantly less frequent (7.3% vs. 28.6%; p < 0.00001) in that group of patients. Women in follicular phase presented vasodepressive response during HUTT more often than woman in the luteal phase (10.0% vs. 4.1%, p < 0.00001). Conclusions: Among women referred for HUTT, the prevalence of the vasovagal syndrome did not differ between those that were pre- and post-menopausal. Higher incidence of vasodepressive reaction in postmenopausal women was observed. Among the premenopausal women, the vasodepressive type of vasovagal syndrome occurred more often in follicular then in luteal phase

Secret-Sharing for NP

A computational secret-sharing scheme is a method that enables a dealer, that has a secret, to distribute this secret among a set of parties such that a "qualified" subset of parties can efficiently reconstruct the secret while any "unqualified" subset of parties cannot efficiently learn anything about the secret. The collection of "qualified" subsets is defined by a Boolean function. It has been a major open problem to understand which (monotone) functions can be realized by a computational secret-sharing schemes. Yao suggested a method for secret-sharing for any function that has a polynomial-size monotone circuit (a class which is strictly smaller than the class of monotone functions in P). Around 1990 Rudich raised the possibility of obtaining secret-sharing for all monotone functions in NP: In order to reconstruct the secret a set of parties must be "qualified" and provide a witness attesting to this fact. Recently, Garg et al. (STOC 2013) put forward the concept of witness encryption, where the goal is to encrypt a message relative to a statement "x in L" for a language L in NP such that anyone holding a witness to the statement can decrypt the message, however, if x is not in L, then it is computationally hard to decrypt. Garg et al. showed how to construct several cryptographic primitives from witness encryption and gave a candidate construction. One can show that computational secret-sharing implies witness encryption for the same language. Our main result is the converse: we give a construction of a computational secret-sharing scheme for any monotone function in NP assuming witness encryption for NP and one-way functions. As a consequence we get a completeness theorem for secret-sharing: computational secret-sharing scheme for any single monotone NP-complete function implies a computational secret-sharing scheme for every monotone function in NP

Simulation studies of annihilation-photon's polarisation via Compton scattering with the J-PET tomograph

J-PET is the first positron-emission tomograph (PET) constructed from plastic scintillators. It was optimized for the detection of photons from electron-positron annihilation. Such photons, having an energy of 511 keV, interact with electrons in plastic scintillators predominantly via the Compton effect. Compton scattering is at most probable at an angle orthogonal to the electric field vector of the interacting photon. Thus registration of multiple photon scatterings with J-PET enables to determine the polarization of the annihilation photons. In this contribution we present estimates on the physical limitation in the accuracy of the polarization determination of $511$~keV photons with the J-PET detector.Comment: Submitted to Hyperfine Interaction