bluuebunny/crossref_metadata_2025 huggingface dataset:
Error analysis of students with Concrete Sequential Thinking Styles in Solving Elimination-Substitution Problems
Authors: Winarti J S , Gembong S , Murtafi’ah W , Apriandi D
Published: March 2020

This study aims to find out the errors of students with concrete sequential thinking in solving the problem of Elimination-Substitution. Error analysis is revealed based on Newmann’s theory. The research method used is a qualitative approach. The subjects of the study consisted of 2 students with concrete sequential thinking skills selected from 32 students of eight grade of SMPN 1 Sawahan. Data collection is obtained through structured interviews. Data analysis techniques consist of three lines, namely data reduction, data presentation, and conclusion drawing. The data validity technique using time triangulation. The results showed that students who had concrete sequential thinking styles in solving Elimination-Substitution problems tended to experience Process Skill and Encoding type errors.
Reconsidering astronomy textbooks’ concept about the cause of sun’s gravitational force: A comparison to quasar
Authors: Wikara B , Sutarno S , Suranto S , Sajidan S
Published: March 2020

All astronomy textbooks tell that a quasar has different gravitational force generator compared to sun. A quasar consists of gaseous matter surrounds supermassive black hole. The black hole generates an enormous gravitational force that binds galaxies around. Though on smaller scale, our sun also has strong gravitational force. However, the gravitational force is believed merely comes from sun’s huge mass instead of an existed black hole inside like quasar. Conversely, this paper confirms that the conviction needs to be reviewed. The particles shift postulate (which was obtained through Heisenberg’s uncertainty and wave-particle duality interpretation) and thermal expansion principle denoted that celestial bodies’ gravitational forces depend on their bodies’ temperatures. The hotter their bodies, the weaker their gravitational forces. Hence, sun must have weaker gravitational force compared to planets around it because sun is hotter than them, though it has a huge mass. The planets attract sun by their stronger gravitational forces, while sun itself, considering its endurance from being disunited caused by nuclear fusion and collision among hot molecules, is suspected has immense gravitational force at the core that attracts its body inward. Therefore, sun’s body is attracted inward and outward, yield a binding that creates balance among celestial bodies of our solar system. According to the postulate and principle before, the immense gravitational force inside sun can only be generated by an extremely cold body, allegedly a black hole. As a consequence, we now describe our sun’s structure as a black hole surrounded by gaseous matter, a characteristic that also possessed by quasars. This argument still needs to be verified, but at least gives a new point of view for scholars.
The application of using video scribe on geometry optics material
Authors: Saraswati D L , Dinihari Y , Nurrahmah A , Sari T A , Wiyanti E
Published: March 2020

On the subject of geometry optics, pictures that can facilitate students in understanding the material are needed. Therefore, learning media that can show animations or pictures that can be understood by students are needed. One of the learning media that can be used is video scribe. Video scribe application can show animations and writings in the form of videos. The stages of this product development are carried out by six stages, such as, concept, design, material collecting, assembly, testing, and distribution. The data collection technique used was product evaluation questionnaire. The product evaluation questionnaire is used to assess development products by material experts and media experts. On average, the result of the validation test by material experts obtained a score of 80,11%, in which it is feasible in terms of material. Whereas, the score by media experts was 84,16%, in which it is also feasible in terms of learning media. Based on the results of the feasibility test conducted, Video scribe-based high school physics learning media on the subject of geometry optics has an average value of 82,14% with a very good interpretation. So that this product can be used in a field trial for users to get a product that viable as an alternative learning media in the classroom.
The effect of basic mathematical abilities on learning outcomes of physics education students
Authors: Saraswati D L , Lestari I , Seruni  , Andinny Y , Hikmah N
Published: March 2020

Research has been conducted to determine the effect of basic mathematical abilities on learning outcomes of physics education students in the Measurement Method subject. This is done based on the observations of researchers in the learning process of the Measurement Method. There are significant differences in the teaching and learning process. Students with weak basic mathematical abilities tend to be difficult to understand every materials in the subject. The population of this research is fourth semester students of Physics Education academic year 2018/2019. This research is an experimental research. The method of data collection in this research was taken through basic mathematical abilities test and student learning outcomes test. Data were analysis using regression analysis. From the results of this research, it can be concluded that there is an influence of basic mathematical abilities on student learning outcomes in the Measurement Method subject with a magnitude of influence of 6.7%. It’s means that the success of student learning in the lecture Measurement Method is related to students’ basic mathematical abilities. So it can be said that the final grades of students in the Measurement Method subject is influenced by the basic mathematics ability possessed by the student.
STEM in english language teaching at high schools in central java indonesia: opportunities and challenges
Authors: Susanto D A , Miyono N , Affini L N
Published: March 2020

STEM as an educational enterprise has grown in importance during the past 10 years, articularly in the USA, UK, and other Anglo-Saxon countries [1]. The problem of this study is that what are the opportunities and challenges of implementing STEM in English language teaching at high schools in central java? The research design was a qualitative study using a sheet of structured interview which was distributed to teachers around at district area like; Pati, Semarang, Demak, Jepara, and Ungaran. There were 13 teachers who collected back the instrument and giving the data through their empirical involvement. The participants were the teachers from 6 state high schools and 7 private high schools. In collecting the data, the writers send the questions through email to the group of teachers’ organization and ask them to participate by answering it. The results are; the opportunities of using STEM that is teachers opportune to apply; 1) social media as a tool in teaching media, 2) vlog in supporting a topic of ‘describing a person/a thing’, 3) direct observation onto the nature, 4) short video in conversation, 5) elaborating some texts genres. On the other hand, there are some challenges like; teachers are facing; 1) less skill in using technology, 2) less facility at schools, 3) no socialization about STEM, 4) less teaching media used, 5) less motivation to grow. Writers also declare to recommend teachers to elevate and upgrade their skill in the usage of technology, collaborating nature as the teaching and be aware with the current teaching approach in order to be able to get in the students’ need in the current era.
Workshop on Multimedia Based Learning for Low Level-Education Teachers
Authors: Buntoro G A , Astuti I P , Ariyadi D
Published: March 2020

Education is one aspect that cannot be separated from human life. Even today education can be said to be the primary human need. Formal education in Indonesia starts from the childhood level or is often called kindergarten. To educate children, more interesting methods and media are needed to foster early talent and interest in students. In this case, kindergarten teachers are expected to maximize their communication skills and creativity in preparing to teach. Technology in our life today, many aspects is expected to be able to keep up with technological advances that have increased rapidly from year to year, including kindergarten teachers. Of the many kindergarten teachers present, there are still those who have not mastered the computer skill. However, with the holding of this training, kindergarten teachers slowly became masters of computers skill so that they were more creative and innovative in utilizing ICTs to create learning media especially those on multimedia based.
Mathematics Pre-Service Teachers’ Analogical Reasoning toward Calculus Problems
Authors: Agustina E N S , Sukriyah D , Dhewy R C , Ayuningtyas N , Mubarokah  , Isobar A
Published: March 2020

The purpose of this study is to describe the relationship between the educational background of Mathematics Pre-Service Teacher (MPST) at senior high school and their analogical reasoning ability (MPST) in solving calculus problems. The sample of this research is 31 MPST from STKIP PGRI Sidoarjo which consists of 18 MPST with high school natural science background, 3 MPST with social high school education background, 1 MPST with language school education background, 6 MPST with a vocational education engineering background, and 3 MPST with vocational education nonengineering background. The method of this research is quantitative method that uses non-parametric statistics namely correlation 2 (Chi-Square) This study shows that the value of 2 is 6,372. It can be concluded that there is no significant correlation between the educational background of MPST and analogical reasoning.
The implementation of Problem Based Learning (PBL) to develop student’s soft-skills
Authors: Brata D P N , Mahatmaharti A K
Published: March 2020

Currently, various implementation of higher education curriculum is still oriented at development of hard skills. Meanwhile, global market requires graduates with both hard skills and soft skills. Graduates’ soft skills are mainly affected by teaching strategy and model used by their lecturers. This current research aims at describing the implementation of a teaching model, i.e. Problem-based Learning (PBL) and effects of the teaching model on students’ soft skills. Descriptive qualitative was employed as the research approach. Triangulation of data source and method was implemented to collect the data, and case study was used to analyze the data. This research resulted that the implementation of PBL in Anthropology Course is learning in which problems are presented to reconstruct the culture of rural community. Students worked in a team to solve authentic problems in a community, developed and presented their way of solving the problems, as well as evaluated the process of solving the problems. The effect of the implementation of PBL was the students understood the course material contextually, were skillful in collecting qualitative data, were more knowledgeable in facing the village community, improved their soft skills in terms of written and spoken communication, a way of thinking (critical, creative, and logic), problem solving skills, team working, and interpersonal and work ethics. As an effort of strengthening students’ characters to face revolution industry 4.0, this research showed that graduates should have skills of 4 Cs (Critical Thinking, Creativity, Communication, and Collaboration Skills).
Analysis of Students’ Ability In Solving Relation and Functions Problems Based on Learning Indicators
Authors: Masjudin  , Muzaki Ahmad , Kurniawan Ade , Yuntawati  , Suhaini
Published: March 2020

The purpose of this study is to describe the ability of students to solve relation and function problems in based on the learning indicator perspective. This type of research is a qualitative descriptive study. This research was conducted at two Madrasah Tsanawiyah (MTs) schools in West Lombok with 79 students. This research instrument includes a diagnostic test sheet and interview guidelines. The procedure of this study includes the provision of diagnostic test sheets to obtain the level of student ability. Furthermore, with a purposive sampling technique interview samples were set. Based on the results of the study obtained information that the ability of students to solve the problem of relations and functions are in the low category. Based on the learning indicators obtained the following findings: (1) the ability of students to explain the definition of relations and functions are in the low category; (2) the ability of students to determine examples and not examples of functions is in the medium category; (3) students’ ability to determine the domain, codomain, and range of a function is in the medium category; (4) students’ ability to draw Arrow and Cartesian Diagrams are in the medium category; (5) students’ ability to determine the value of a function if the value of the variable is known to be in the low category; (6) students’ ability to determine the value of a variable if the value of the function is known to be in the very low category; and (7) the ability of students to make function formulas is in the very low category
The Prototype of Automatic Water Sprinkle with Soil Moisture Sensor Based on ATMega 8535
Authors: Latif Abdul , Megantoro Prisma
Published: March 2020

This paper presents the design and realization of a ATMega8535 microcontroller based instrument for measuring soil moisture. Two probe for soil moisture sensor. This soil moisture sensor is connected to signal generator. When the soil moisture changes, then the impedance of sensor will change. This the frequency of output signal generator changes according to the soil moisture. This frequency change is then detected and used for knowing the soil moisture level. The instrument is also equipped with an on-off control signal that can be used for controlling the soil moisture level.
The Use of ICT in Teaching: Lecturers’ Perceptions, Obstacles, and Expectations
Authors: Bansa Y A , Asrini
Published: March 2020

Since the technology has been developed, Educators should consider this to be a value for educational purposes. In millennial teaching, the use of ICT is common nowadays especially in higher education. The use of ICT is meaningful and helpful for lecturers to enhance their teaching performance. This study attempts to investigate the lecturers’ perceptions, lecturers’ obstacles, and lecturers’ expectations on the use of ICT in teaching. The researcher sees a need to carry out this study as it provides a platform to discover pedagogical implications that would benefit the lecturer in terms of using ICTs as media in their teaching. The respondents of this research were 40 lecturers in higher education of economics study in Sumatra, Indonesia. The lecturers’ perceptions, lecturers’ obstacles, and lecturers’ expectations were measured through a questionnaire and an interview. The findings showed most of lecturers had positive perception towards it, limited knowledge and limited understanding on how to integrate ICT into teaching which were dominant obstacles for respondents when using ICT into teaching. Respondents hope that an increased use of the computer would make the class more interactive, to use computers to do more interesting and imaginative work, computers could be used to provide more interactive activities for students, would provide students with more practical and useful knowledge, and they need tutor to teach how to use software or how to integrate ICT into teaching. The results of this study is beneficial for educators in incorporating ICT into their teaching repertoire.
Primary Valuation of Coastal Flood Impact to Fish Farming in Brebes, Central Java
Authors: Nirwansyah Anang Widhi , Suwarsito
Published: March 2020

High tide event has been recognized in most of coastal area especially in urban region. Meanwhile, there is still limited interest on tidal flood impact on non-urban area including fish farming in developing region. This study aims to identify coastal flood due to high tide event in Brebes, Central Java and its impact on fish farming area. Here we local information from in-depth interview to local group of fish farming and Geographic Information System (GIS) within inputs from national seamless Digital Elevation Model (DEM) data from \ Geospatial Agency (BIG), and land use data from Google Earth. Additionally, this study also propose local context of coastal flood events on mapping the impact upon fish farming area. This research found that 3,309.53 ha of fish farming area has been flooded in the morning event of and 4,810.32 ha in the afternoon of mangsa peteruan. Meanwhile, in mangsa lanjar, the morning event has submerged around 4,521.72 ha, and 3,703.17 ha for afternoon event. This study depicts beneficial information for coastal zone planning as well as coastal disaster risk management in Indonesia.
Bioprospects From Clamshell Of Geloina Sp As Calcium Substitution Material for Poultry In Indonesia
Authors: Tumisem  , Ramadhan Satriya
Published: March 2020

In Indonesia the use of clamshell for calcium substitution of poultry has not been implemented. Some research results suggest that clamshell have very high calcium levels. Clamshell can be used as an enhancer of calcium levels in animal feed, especially in poultry. Increased calcium levels in poultry will help in the process of forming eggshells. The calcium needs of poultry farmers in Indonesia meanwhile are being met from snail intake. This intake is needed by farmers, especially for improving the quality of the yolk, in addition to the formation of eggshells. Clamshells of Geloina sp. In Indonesia there is still not much utilization. Thus this study aims to analyze the calcium content of Geloina sp mussels as calcium substitution material for poultry and the condition of poultry eggs produced by farmers. The design or approach in this study was a quantitative research with survey and experiment. The method used in this study was a laboratory and farmers. Activities applied in laboratory during the study consisted of two activities, namely: 1) sample preparation and 2) analysis of substance elements and chemical compounds with Atomic Absorption Spectrophotometer method (AAS). The results showed that the Powder Clamshell of Geloina sp. had and average elements and chemical compounds contained were Ca level (94.90%), Na level (0.48%), P level (not detected), and CaCO3 level (7.76%). Element and chemical compounds levels contained in the Powder Clamshell of Geloina sp. had a great potential if it was used and treated as good as possible. It can be an alternative solution in the prevention of waste powder clamshell of Geloina sp.) untapped, furthermore it could be applied to the manufacture of products to give added value to support the economy of rural communities in Indonesia. The results of poultry eggs in the third treatment (addition of rations with shellfish powder as much as 35%) have the ability to lay eggs every day with an average frequency of 1 day 1 egg. From the results of this activity it was proven that 65% of poultry had an increased frequency of laying eggs.
Disaster mitigation tutorial based on android
Authors: Mustafidah Hindayati , Febriyanto Erwin , Suwarsito  , Sriyanto Sriyanto
Published: March 2020

A natural disaster is a situation where an unexpected arrival. In that condition damage and even death can occur for humans, animals and plants. The occurrence of natural disasters cannot be prevented, but the community can minimize the impact that occurs by seeking knowledge about how to reduce the impact of disaster risk or what is called disaster mitigation. The development of android-based technology is very popular with the community as a tool for communication and other work. Therefore this research develops a natural disaster mitigation application that can be run on an android phone. This tutorial application is built using Adobe Flash and uses the programming language Actionscript 3.0. The application development method uses the Multimedia Development Life Cycle (MDLC) model with six stages namely concept, design, material collecting, assembly, testing, and distribution. The seven types of natural disasters conveyed in this application are natural disasters that often occur in Indonesia, namely earthquakes, landslides, floods, volcanic eruptions, tornadoes, fires, and tsunamis. This tutorial application provides an explanation of the understanding of each type of natural disaster, how to reduce the impact of disaster risk, and a scientific video on the process of disaster occurrence. This application can be run does not have to use internet access to access information in it, so it can be used at any time.
Utilization of Lightweight Brick Waste Material As a Mixture of Laston AC - WC
Authors: Mirring Palinggi Monika Datu , Elizabeth
Published: March 2020

The use of lightweight bricks that are used as walls in buildings is waterproof and strong in bearigng the burden on the building flor, but after the building is demolished, the demolition of the building is recycled to function as a pavement material on the road surface as a mixture of Laston AC – WC, so waste from the building is functioning again and is not just thrown away.

In this study using lightweight brick building waste material as a filler so that this demolition waste produces a positive value for building demolition waste. As for designing the Laston AC – WC using coarse and fine aggretes from Bili – Bili Gowa Regency with 60/70 penetration asphalt, the mixture is substituted with Cement to get a Conventional Marshall tes and Immertion to get a Time Strenght Index (IKS) as well as in the AC – WC laston mixture through marshall Immersion testing

This research methodology is carried out in the from of testing the characteristics of coarse aggregates and fine aggregates, fillers and asphalt that meet the specification standars and then made a mixture composition design then making test specimens that produce a mixture of Laston AC – WC and then testing to obtain the characteristics of Conventional Marshall. And to get the Marshall Immersion, test Immersion is done in determining the immersion Index (IP) / Residual Strength Index (IKS).

The results of this experimen wiht a combination of lightweight brick filler 0%: 100% Cement filler, 25% lightweight brick fille : 75% Cement filler, 50% lightweight brick filler : 50% Cement filler, 75% lightweight : 25% Cement filler, 100% lightweight : )% Cement filler, characteristics at optimum conditions for mixture of Laston AC – WC use 100% lightweight brick waste then VIM 4,18%, VMA 15,10%, Stability 2400,41 kg, Flow 3,40%, Marshall Quantien (MQ) 706,30% and IKS 92,31%.
The Contribution Of Heterogeneous And Homogeneous Catalysts Towards Biodiesel Quality
Authors: Pasae Yoel , Tangdilintin Srianti , Bulo Lyse , Allo Eda Lolo
Published: March 2020

Homogeneous catalysts and heterogeneous catalysts are two types of catalysts used in the transesterification reaction process to produce biodiesel. Homogeneous catalysts that are commonly used are NaOH and KOH, while heterogeneous catalysts are CaO, super base CaO and Zeolite. This research was conducted to determine the contribution of catalysts NaOH, CaO, super base CaO, and zeolite to the quality of biodiesel produced from bulk palm oil, The reaction process is carried out in a Stirred Tank Flow Reactor equipped with a condenser. The results showed that the use of homogeneous catalysts could increase the acquisition of biodiesel but generally triggered high acid levels in the reaction products. Whereas heterogeneous catalysts can reduce biodiesel acid numbers, although the acquisition of biodiesel is lower than homogeneous catalysts.
Simulation Of Bod And Cod Pollutants Distribution In Tello River Makassar City
Authors: Apriyani Ika , Radjawane Louise Elizabeth
Published: March 2020

Water quality management and water pollution are one of the natural resources that have a very important function for human life that must be managed and secured from the conditions of pollution, therefore efforts are needed to monitor and monitor river water quality. In connection with that, a study was conducted aimed at assessing changes in water quality in the Tallo River through the distribution of pollutant concentrations of BOD (Biological Oxygen Demand), DO (Dissolved Oxygen) and COD (Chemical Oxygen Demand) by analyzing the mathematical model approach in the form of Surface Software Water Modeling System (SMS 8.1) integrated with RMA2 and RMA4. The research method carried explanation was a field survey in the form of data collection of water as many as 5 points in the drainage along the Tallo River. Simulation results show that based on water content requirements in the Republic of Indonesia Government Regulation No. 82/2001 regarding water quality standards it is known that for existing conditions and simulation results it is known that the classification of estuary river water conditions based on Dissolved Oxygen (DO) content is classified as Class 4 and the content of Biochemical Oxygen Demand (BOD) is classified as class I and the content of Chemical Oxygen Demand (COD) is categorized as class IV.
The Effect Of Fumigation Treatment Of King Pineapple Leaf Fiber (Agave Cantala Roxb) On Length Of Fiber Critical Using Epoxy Matrix
Authors: Palungan Musa Bondaris , Tangaran Benyamin , Salu Salma , Tikupadang Karel
Published: March 2020

The purpose of this research was to determine the critical length of the king pineapple leaf fiber (KPLF) due to fumigation treatment with time variations. To determine the critical length is done by pull out test. The pull-out test was conducted to determine the adhesive properties of the KPLF interface with the epoxy matrix by implanting KPLF without and with the fuming treatment into the epoxy matrix then being withdrawn with a certain load and in quantity it can provide tensile stress information which can then be converted into a shear stress fiber with epoxy matrix. The measurement results show the effect of fogging treatment for 15 hours on KPLF, can increase the shear stress of the epoxy matrix interface by 16.75 MPa with a length of 1 mm and a critical length of 4,53 mm.
Model based characterisation of delamination by means of thermographic inspection
Authors: Ratsakou Almpion , Reboud Christophe , Skarlatos Anastassios , Lesselier Dominique
Published: March 2020

The objective of the work presented in this paper is to propose a fast and accurate approach for the characterisation of the delamination in single-layer metallic planar pieces using infrared thermography. This approach is based on a combination of pre-processing techniques and inversion. The inversion has been done in a reduced parameter space since the preprocessing phase gives us information about the location and the shape of the flaws in the transverse plane. The estimation of the flaws’ parameters has been carried out by an iterative data fitting method involving a fast semi-analytical three-dimensional model. The robustness of the proposed approach is numerically assessed in presence of synthetic noisy data sets in different configurations.
NDT/NDE by means of a probabilistic differential compressive sensing method
Authors: Gottardi Giorgio , Hannan Mohammad Abdul , Polo Alessandro
Published: March 2020

A novel microwave imaging (MI) method is proposed to deal with the nondestructive testing and evaluation (NDT/NDE) of dielectric structures. The proposed technique exploits a probabilistic differential contrast source inversion (D-CSI) formulation of the inverse scattering (IS) problem, which is then effectively solved by means of a customized multi-task Bayesian compressive sensing (MT-BCS) solver. Numerical results are shown to assess the effectiveness and robustness of the proposed NDT/NDE method, as well as to compare it. with a single-task (ST-BCS) implementation within the same framework.
Regularization Techniques for Inverse Problem in DOT Applications
Authors: Benfenati A , Causin P , Lupieri MG , Naldi G
Published: March 2020

Diffuse optical tomography (DOT) is an emerging diagnostic technique which uses near–infra–red light to investigate the optical coefficients distribution in biological tissues. The surface of the tissue is illuminated by light sources, then the outgoing light is measured by detectors placed at various locations on the surface itself. In order to reconstruct the optical coefficients, a mathematical model of light propagation is employed: such model leads to the minimization of the discrepancy between the detected data and the corresponding theoretical field. Due to severe ill–conditioning, regularization techniques are required: common procedures consider mainly ℓ
1–norm (LASSO) and ℓ
2–norm (Tikhonov) regularization. In the present work we investigate two original approaches in this context: the elastic–net regularization, previously used in machine learning problems, and the Bregman procedure. Numerical experiments are performed on synthetic 2D geometries and data, to evaluate the performance of these approaches. The results show that these techniques are indeed suitable choices for practical applications, where DOT is used as a cheap, first–level and almost real–time screening technique for breast cancer detection.
Sparse recovery for inverse potential problems in divergence form
Authors: Baratchart Laurent , Villalobos-Guillen Cristobal , Hardin Douglas , Leblond Juliette , Saff Edward
Published: March 2020

We discuss recent results from [10] on sparse recovery for inverse potential problem with source term in divergence form. The notion of sparsity which is set forth is measure- theoretic, namely pure 1-unrectifiability of the support. The theory applies when a superset of the support is known to be slender, meaning it has measure zero and all connected components of its complement has infinite measure in ℝ3. We also discuss open issues in the non-slender case.
Frequency-based inversion of a single wireless link for indoor passive target detection
Authors: Gottardi Giorgio , Abdul Hannan Mohammad , Polo Alessandro , Salucci Marco , Viani Federico
Published: March 2020

In this work, the wireless detection of transceiver-free targets is formulated as an inverse problem and solved using the received signal strength of existing wireless devices. The main goal of the proposed solution is to opportunistically exploit a single wireless link established between two commercial wireless access points for the real-time detection of humans entering the monitored domain. The proposed computational method exploits both an empirical mode decomposition for denoising and a discrete Fourier transform for filtering the received signal strength. A reduced set of highly informative features are used for the automatic learning of a support vector machine classifier and the prediction of target absence/presence probability. A preliminary experiment carried out in a real indoor test site is presented to assess the advantages and limitations of the proposed inversion method.
PCA-Based inversion of WiFi signal for robust device-free indoor target detetion
Authors: Gottardi Giorgio , Abdul Hannan Mohammad , Li Baozhu , Polo Alessandro , Salucci Marco , Viani Federico
Published: March 2020

The spatial and frequency diversity introduced by the recent WiFi standards based on orthogonal frequency-division multiplexing is exploited for the robust wireless detection of device-free targets 111 indoor environments. The arising inverse problem is solved by decomposing the channel state information by means of a customized strategy based on the principal component analysis (PCA) for extracting target-dependent, components from the WiFi signal. The experimental validation of the proposed solution pointed out a robust target detection with failure rates lower than 3 [%] using a single wireless link already deployed in a real office test, field.
A computational inversion method for interference suppression in reconfigurable thinned ring arrays
Authors: Boulos Federico , Dall’Asta Luca , Gottardi Giorgio , Abdul Hannan Mohammad , Polo Alessandro , Salas-Sanchez Aaron , Salucci Marco
Published: March 2020

An inversion strategy for dynamically thinning (i.e.. turning on and off) the radiating elements of ring arrays in order to maximize the signal-to-noise ratio is presented. Since thinned arrays provide only average sidelobe performances, but. the directions of arrival (DoAs) of interferences can be arbitrary, a set. of thinning configurations that. guarantee a sufficient interference rejection in the whole angular region outside the main lobe is off-line selected. The on-off status of the array elements is then dynamically switched among such precomputed thinning sequences until the one providing the best, signal-to-interference performance is identified. A set of numerical results is reported and discussed to assess the effectiveness and potentialities as well as current limitations of the dynamic thinning approach in dealing with interference suppression of ring arrays.
Quantum mechanics in magnetic backgrounds with manifest symmetry and locality
Authors: Davighi Joe , Gripaios Ben , Tooby-Smith Joseph
Published: March 2020

The usual methods for formulating and solving the quantum mechanics of a particle moving in a magnetic field respect neither locality nor any global symmetries which happen to be present. For example, Landau’s solution for a particle moving in a uniform magnetic field in the plane involves choosing a gauge in which neither translation nor rotation invariance are manifest. We show that locality can be made manifest by passing to a redundant description in which the particle moves on a U(1)-principal bundle over the original configuration space and that symmetry can be made manifest by passing to a corresponding central extension of the original symmetry group by U(1). With the symmetry manifest, one can attempt to solve the problem by using harmonic analysis and we provide a number of examples where this succeeds. One is a solution of the Landau problem in an arbitrary gauge (with either translation invariance or the full Euclidean group manifest). Another example is the motion of a fermionic rigid body, which can be formulated and solved in a manifestly local and symmetric way via a flat connection on the non-trivial U(1)-central extension of the configuration space SO(3) given by U(2).
Study on the Influence of Jelly in Polymer Flooding Injection System on Oil Displacement Efficiency
Authors: Xu Quan
Published: March 2020

In this paper, the composition and production conditions of viscous gelatinous substances in the inner walls of filters and pipelines in polymer injection system are analyzed in detail, and the influence of gelatinous substances on the development effect of polymer flooding is studied. A new understanding of the influence of gelatinous substances on the development effect of polymer flooding is obtained. In view of the harmfulness of gelatinous substances, treatment suggestions are put forward and positive countermeasures are taken for industrial field. It has important reference value.
Determination of Arctiin in Xiaoer Qingyan Granules by Capillary Electrophoresis
Authors: Liu Haixing , Wang Lintong
Published: March 2020

This paper investigated the determination of arctiin content in Xiaoer Qingyan granules by high performance capillary electrophoresis (HPCE) method. The borax solution of 37.5 mmol concentration containing 12.5% methanol was chosen as buffer solution. The experiment was performed at a constant voltage of 16 kV and UV detection wavelength of 277 nm. The content of arctiin in Xiaoer Qingyan granules was 3.678mg/g (RSD=1.72%) (n=6). The recovery was in the range of 80.9%-113.4% (n=6). This method is suitable for the detection of the content of arctiin in Xiaoer Qingyan granules.
Experimental Investigation of Wear Behaviour of 40MnB
Authors: Ma Xuejiao , Chen Bo , Feng Kun , Zhu Pengxiao
Published: March 2020

Dry sliding wear (pin-on-disc) tests were carried out under different loads and sliding speeds at room temperature for 40MnB. The present work attempts to explore wear mechanism of 40MnB. Compared with friction speed, it was found that the effect of load is more obvious. At a certain friction speed, the wear loss increase obviously with the increase of load, and the friction coefficient increases at first and then decreases slightly. Increased load leads to higher shear stress and higher interface temperature, thus cause the contact point to adhere and peeled. On the other hand, under a certain load, the friction speed has little effect on the wear rate. Surface temperature increases with the increase of friction speed, making easier plastic flow of the steel. The wear mechanism of 40MnB is adhere wear and abrasive wear.
Strength Prediction Model of High Strength Fly Ash Concrete Based On Mixed Kernel Function
Authors: Zhao Zhongling , Li Jing , Feng Xiwen , Wang Xiao , Gao Mengying
Published: March 2020

In this paper, the proportion of fly ash in cementitious material, the amount of cementitious material and the ratio of water to cement are selected, and the rough set theory is used to process the data. A mixed kernel function support vector machine prediction model with conditional attribute as input and decision attribute as output is established to explore the influence of three factors on the strength of high strength fly ash concrete. The prediction model with high prediction accuracy is selected for optimization. According to the existing test data, the variation law of concrete strength with proportioning parameters is summarized.
Preliminary Study on Antimicrobial Activity of Fermentation Broths of Oudemansiella Mucida
Authors: Deng Xu , Li Risheng , Zhang Yimei , Li Rongrong
Published: March 2020

Oscillation culture was carried out on Oudemansiella mucida., the obtained fermentation broths were extracted with ethyl acetate, n-BuOH in succession to give three sections: extract of ethyl acetate, n-BuOH and the remained fermentation broths. Their antimicrobial activities against five common phytopathologenic funguses were determined by filter paper method and solid culture medium method. The result indicated that the fermentation broths markedly inhibited five phytopathologenic funguses. The metabolites with antimicrobial activity were mainly congregated in EtOAC extract, with the minimal inhibiting concentration (MIC) for Alternaria brassicae, Alternaria longipes and Gloesporum fructigenum being 10 mg/mL, the MIC for Fusarium graminearum and Alternaria alternata being 5mg/mL.
Preparation and Application of Flexible Conductive Fabric Based on Silk
Authors: Zheng Songming , Xu Chuanqi , Zhang Kaiwei , Yang Xin , Li Ranran , Liu Yuqing
Published: March 2020

Applications in wearable and implantable electronic information products have increased in recent years, and traditional conductive materials have poor flexibility. To meet the trend of flexible, wearable and implantable electronic devices, flexible conductive materials are widely accepted. Here, we report on a method of preparing a flexible conductive textile material. The graphene is finished onto the surface of the silk fabric by multiple impregnation-reduction methods, and the silk fabric retains good flexibility while obtaining conductivity. Flexible conductive silk also has a good temperature and strain response, and its electrical resistance changes with temperature and strain. The obtained flexible conductive silk fabric has the advantages of both silk fabric and graphene, it has broad application prospects in wearable devices, health care monitoring, and human-machine interface.
A Discriminant Analysis of the Financial Indicators of the Innovative Pharmaceutical Enterprises
Authors: Zhang Yuanyuan , Jia Yu
Published: March 2020

This study examines the value relevance of financial indicators and pharmaceutical innovation. Discriminant analysis is used to study the difference of the financial indicators of innovative pharmaceutical enterprises and the generic pharmaceutical enterprises during the sample period between 2013 and 2017. The results show that operational capacity, debt-paying ability, growth capacity and research and development capabilities are important indicators for identifying innovative pharmaceutical companies. Investors can take these financial indicators into consideration when measuring the innovation ability of pharmaceutical enterprises.
Influence of the external flow on the departure of vapor bubbles
Authors: Shan Xiaopeng , Nie Deming
Published: March 2020

The two-dimensional lattice Boltzmann method (LBM) is used here to numerically study the behaviors of phase change and vapor bubble departure in the presence of external flow. The external flow is induced by the action of shearing applied on the top boundary in this work. The bubble departure pattern is preliminarily revealed under different intensities of shearing. Furthermore, the influence of external flow on the heat transfer is examined. It has been found that the vapor bubbles are likely to depart from the heated plates in an alternative way. The external flow is shown to greatly enhance the heat transfer between the heated plates and the cold liquid. The velocity fields are also presented.
Synthesis and sustained release mechanism of slow release polycarboxylate superplasticizer
Authors: Sun Jian , Yin Xueyu , Cui Bo , Zhao Chunyu , Miao Guikun
Published: March 2020

Based on the research and experiment on the mechanism of carboxylate ion protection and release, based on this system, it is determined that dimethyl carboxylic acid is the main sustained-release component, and then the sustained-release system is optimized to obtain excellent performance. A slow release polycarboxylate superplasticizer. Through the experiment of different cement compatibility, water-reducing agent saturation, concrete slump retention and mechanical properties, the dosage, working performance and strength of the target slow-release polycarboxylate superplasticizer were clarified. It is proved that the experimentally prepared sustained-release polycarboxylic acid superplasticizer has a good sustained release effect in application.
A bendable solid-state supercapacitor based on alkaline polyvinyl alcohol
Authors: Sha Zhiyuan
Published: March 2020

Flexible electrochemical double layer capacitors (EDLCs) based on polyvinyl alcohol (PVA) electrolytes are fabricated. During the process, electrode materials are mixed into a film and pressed on the current collector instead of the traditional coating method. In order to explore the electrochemical performance of this kind of supercapacitors, a series of testing method including cyclic voltammetry, Galvano static charge discharge testing and electrochemical impedance spectroscopy. It is revealed that the electrochemical capacitor based on PVA exhibits excellent electrochemical performance and long cycle life. The specific capacitance for the EDLC based on PVA reaches 187F/g at the current density of 1A/g, and the specific capacitance decreased with the increasing of the scanning rate. The results indicate that the supercapacitor cell capacitance keeps more than 70% after 10000 charging and discharging cycles.
A Multi-Feature Fusion Based Vehicle Logo Recognition Approach for Traffic Checkpoint
Authors: Ding Sha , Wu Hongyang
Published: March 2020

In this paper, we propose a vehicle logo recognition algorithm based on multifeature fusion using a hierarchical classification approach, which can be applied at traffic checkpoints. First, a typical database of vehicle logos is set up based on surveillance images recorded at traffic checkpoints. Next, three features, HOG, Curvature histograms, and GIST, are extracted and three corresponding first level classifiers are trained using the support vector machine (SVM) algorithm. The probability that a certain test sample belongs to a certain kind can be obtained by predicting the sample with each level-1 classifier. All these probabilities are then concatenated and used as features for training a second-level SVM classifier. The resultant new classifier is used for classifying the vehicle logos of the test set. The experimental results show that the proposed approach to hierarchically integrate multiple features provides excellent accuracy for the vehicle logo recognition task.
Study on acoustic properties of multilayer impedance materials
Authors: Su Jintao , Zheng Ling , Wang Bangdong
Published: March 2020

Composite materials are produced using advanced material preparation techniques to optimize a combination of materials with different properties to form new materials. Such materials have the composite properties of their constituent materials. Composite materials have been widely explored for their use in the field of acoustic noise reduction as well as in automobile, aviation, and other fields. To further enhance the acoustic characteristics of composite materials, this letter proposes a multilayer composite structure comprising a resistive screen structure material (perforated screen material), foam, and fiber. The impedance tube method is used to investigate the rigid wall absorption performance and flow field transmission loss in seven types of resistive screen composite materials of various flow resistivities and porosities. The results show that the acoustic absorption and acoustic insulation performance of the resistive screen composite material are better than the foam–fiber multilayer material. The maximum acoustic absorption coefficient reached 0.95 at 3000 Hz and the maximum difference in sound reduction was 6.5dB. This resistive screen material provides a new dimension to the design of new materials.
Effect of Morphology on Electrochemical Performance of Chalcopyrite Cathode
Authors: Ding Wei , Bi Dapeng , Shen Jie
Published: March 2020

Chalcopyrite was synthesized with various reaction precursors and solvents, and plate-, rod-, and sphere-like chalcopyrite can be obtained. Our results show that rod-like chalcopyrite has higher discharge capacity, better rate capacity and cycle performance than others.
Research and application of a domestic system of wind power directly stirring heating---Taking northeast China as an example
Authors: Zhang Linghan , Yao Qiuchen , Ke Li
Published: March 2020

In northeast China, wind in winter is strong and its energy has high sustainability, so this new type of household wind power stirring heating system focuses on stirring liquid(paraffin oil mixed with water according to the ratio of 1:1)by wind power directly, which eliminates the conversion of electrical energy and has high efficiency. The system causes energy saving and emission reduction and improves the conversion efficiency. In order to improve the situation where heating relies on coal burning or straw burning in rural areas in winter, based on the principle of energy saving, emission reduction, environmental protection and economical principles, we combine the wind energy and heating tactfully and it truly adjusts measures to local conditions.