bluuebunny/crossref_metadata_2025 huggingface dataset:
Islamism, the West and Our Concern: A Social Reflection
Authors: Aisyah TI , Sahrasad Herdi , Ridwan Muhammad , Mulky Muhamad Asrori , Tabrani Dedy , Chaidar Al
Published: August 2020

This article argues that a number of Western orientalists tried to impress that Islam and the West could not meet, imaged that all the Islamic ones seemed to be unable to meet all the nuances of the West, as all the western images imaged always contradict Islam. Such tensions continue to this day. Towards the end of the 20th century, Islamism or Islamic fundamentalism has retreated or failed in maintaining political power in the Islamic world. But the enforcement of Shari'ah in society, remains a central theme of the demands of these Islamic fundamentalists. Thus, their target as a group is no longer just a country, but also a society. The political experiments of Islam, however, as shown in Algeria, Sudan, Iran and Afghanistan have failed and are out of date, but anyway, by the beginning of the 21st century Islamism or Islamic fundamentalism has been revived, marked by the WTC bomb 9/11 and other terror attacks in Indonesia, Europe, the US etc.
The Implementation of Jigsaw Type Cooperative Learning Model to Improve Student Learning Outcomes of Senior High School Seulimun in Aceh Besar Regency
Authors: Ismail Ismail
Published: August 2020

Application of Jigsaw Cooperative Learning Model to Improve Learning Outcomes of Social Science Learning in 11th grade social studies (IPS-2) Senior High School Seulimum Aceh Besar Regency. The aim of the research is to improve student learning outcomes in learning Social Sciences in 11th grade IPS-2 Senior High School Seulimum Aceh Besar Regency in the 2017/2018 school year by using Jigsaw cooperative learning, the subjects in this study were all students of 11th grade IPS-2 Senior High School Seulimum Aceh Besar Regency in the 2017/2018 school year as many as 34 people. The research conducted was a class action research (Classroom Action Research) which was conducted for (3) months, from March to May, in 2 cycles, which became. Each cycle consists of 4 stages, namely planning, action, observation, and reflection. The research data were obtained through learning outcomes tests, observations, interviews and documentation studies. The data analysis technique used in the study was qualitative descriptive analysis. The validity of the data uses the technique of triangulation of data sources. The conclusion of the study is the application of Jigsaw cooperative learning can improve the activities and learning outcomes of students in learning Social Sciences in 11th grade IPS-2 Senior High School Seulimum Aceh Besar Regency in the academic year 2017/2018. The results of observations showed the average indicator of student learning activities in learning Social Sciences in the first cycle was 63.29% and in the second cycle was 87.85%. From cycle I to cycle II it increased by 24.56%. The results of knowledge test material excretion system in humans also increased in the first cycle was 65.67 and in the second cycle 80.51, from cycle I to cycle II increased by 14.84. I was 78.41 and in the second cycle 81.78, from cycle I to cycle II increased by 3, 37. Likewise the teacher's performance in the learning process increased from cycle I by 61.0% and in the second cycle 83.50% increased by 22.50.
The Effectiveness of Telegram App in Learning English
Authors: Alahmad Mana
Published: August 2020

There have been enormous improvements in every field in the modernized and technological period. When human understanding advances, several new developments have come to light and Such innovations contribute to human development. Because of the emergence of this modern technology and internet, the field of education is evolving a lot. The usual, blackboard books are replaced by smart boards and e-books. In addition, there is a behavioral shift in the learning of the learners and they rely more on modern technologies. Education, rather than teacher dependence. While teaching English, the teachers bring the new technology into their classrooms using the technology available, they change their methods and techniques to teach the EFL/ESL learners English. In their EFL / ESL classrooms even some teachers encourage   the learners to use mobile phones to make their learning simple. This paper focuses on the studies done on the use of mobile phones in the classrooms. Moreover, the pros of using mobile apps for the learners are discussed.
The Influence of Cooperative Learning Models and Learning Motivation on the Skills of Reading Students in Elementary School 101883 Tanjung Morawa Sub-District
Authors: Wulandari Utari Nur , Ansari Khairil , Hadi Wisman
Published: August 2020

This study aims to: (1) Know the differences in reading skills of students taught with the Cooperative Integrated Reading and Composition learning model compared to students taught with conventional learning models; (2) Knowing the difference in reading skills of students who have high learning motivation compared to students who have low learning motivation; (3) Knowing the interaction between learning models and learning motivation in influencing students' reading skills. The population in this study were the fifth grade students of Elementary school 101883, Tanjungmorawa District, Deliserdang Regency, amounting to 54 people. Data collection in this study was through questionnaires and students' reading skills tests. Hypothesis testing is done by using the Two Way Anova test. The results showed that: (1) The reading skills of students taught with the Cooperative Integrated Reading and Composition learning model were higher than those taught by conventional learning models (Fcount = 21.164 and sig. 0.000> 0.05); (2) Reading skills of students who have high learning motivation are higher than reading skills of students who have low learning motivation (Fcount = 6.756 and sig. 0.012> 0.05); (3) There is an interaction between learning models and learning motivation in influencing students' reading skills (Fcount = 7.054 and sig. 0.011> 0.05).
Consequences of High Population in Teaching and Learning of Computer Courses in Kwara State College of Education, Oro
Authors: Niyi Madandola Tajudeen , Niyi Sakariyau Sherif , Omotayo Salawu , Tina M.O Boye Eni , Olubukola Jimoh Ruth , Salat Junaidi
Published: August 2020

The study scrutinised consequences of high population in teaching and learning of computer courses in Kwara State College of Education, Oro. The population for this study consisted of one hundred and twenty students of department of Computer Science, Kwara State College of Education Oro. Female students participated more in the study than the male students. Students between age brackets of 21 – 25 years have the highest frequency of respondents. Structured questionnaire was designed and used to collect data. The data gathered in section A of the questionnaire was analysed with frequency count and bar chart. The three formulated and tested alternative hypotheses were analysed with chi square statistical tool and all the three were accepted. The study exposed the negative consequences of overpopulated class in teaching and learning of computer courses.
Limbaga (Proverbs) Simalungun as a Source of Forming Character Education
Authors: Purba Asriaty R. , Herlina Herlina , Siahaan Jamorlan
Published: August 2020

This research is entitled Limbaga (Proverbs) Simalungun as a Source of Formation of Character Education. Character education is a human activity to establish peace-loving and prosperous personalities in order to build their own personal character and people around them. Character education is closely related to moral education which aims to shape and practice one's ability to perfect himself in a better direction. Character education has been applied since childhood. Character education can be done in their family, school and community. The purpose of this study is to describe the character values contained in limbaga (proverbss) that can be used as a source of character education. This research belongs to the category of descriptive qualitative research. The results showed that there were 9 (nine) character values contained in the Simalungun limbaga (proverbs) namely: religious, hard working, honest, disciplined, independent, rewarding achievement, responsibility, social care, and peace-loving.
Orcein and Fluorescent Banding Analysis of Two Floral Types of Catharanthus Roseus L.
Authors: Datta Tanusree , Pinky Meghla Saha , Dash Chandan Kumar , Begum Kazi Nahida
Published: August 2020

Two floral types of Catharanthus roseus L. viz. pink and white were studied through differential staining with orcein, CMA and DAPI for cytogenetical characterization and to assist towards updating their taxonomical status and evaluating chromosomal diversity between them. "Simple Chromocenter Type" of interphase nuclei was observed with some darkly stained small heterochromatic regions throughout the nuclei. Most of the prophase chromosomes of Catharanthus roseus (pink and white) were "Continuous Type" and a few were "Gradient Type". Although these two floral types possessed 16 metacentric chromosomes in somatic cells, they showed variation in fluorescent banding pattern considering the modification of GC- and AT-rich repetitive segments. Taking into account all the parameters of both the floral types of C. roseus showed strict symmetric karyotype as well as primitive nature. Therefore, the combined data of differential staining provide information to make comments on their chromosomal status with cytogenetical characterization and also create a baseline for future research.

Dhaka Univ. J. Biol. Sci. 29(2): 219-227, 2020 (July)
Cultura, Estado, diálogo e institucionalidad
Authors: Villamagua Vergara Ramiro Ernesto , Delgado Alexandra , Ogaz Oviedo Felipe , Carvajal Guarderas Patricio , Oviedo Fierro Sara
Published: August 2020

Esta contribución plantea cómo una nueva institucionalidad cultural presupone la cooperación socio-institucional y  un cambio cultural urgente basado en el concepto de gobernanza cultural, "cultura en el quinto poder" o "poder ciudadano",
VISUAL AND VERBAL IN LINE MESSENGER APPLICATION: A SEMIOTIC STUDY
Authors: Wijaya Venice , Zein Tengku Thyrhaya
Published: August 2020

Nowadays, the usage of stickers especially in LINE Messenger is very popular, especially among teenagers. In spite of that, misunderstanding is still happen often. The reasons for choosing LINE stickers are that they are full-sized and expressive so many users can face a misunderstanding while using it. Also LINE provides a wide range of kind of stickers, and that it is very important for users to understand the meaning of each sticker to avoid misunderstanding. This study aims to identify the elements of visual and verbal signs contained in LINE messenger. The method used in this study is a qualitative descriptive method. The data used in this study is 20 visual (stickers) and verbal (texts), in which sticker is the main data meanwhile text is used as supporting data. The source of the data in this study is LINE Messenger. The data was then analyzed by using semiotic theory with a trichotomy model proposed by Charles Sanders Peirce. The results of the analysis show that every sticker contains qualisign aspects such as colors, gestures, etc., but not every meaning contain in the sticker is affected by their quality. It is also shown that every sticker is replica, but it still refers to the law. Every sticker must also share at least one similar characteristic or icon with the object they represents and the sticker used must base on the topic which occurred. The symbol is in the form of key word which makes it easier for the user to choose the sticker variations. Rheme and dicent show that meaning can be derived from the elements contain in the stickers. The differences are rheme contain qualisign and icon, meanwhile dicent only contain secondness aspects. Argument shows that meaning can be derived from hypotheses, standards in society, or even the sign itself. Keywords: LINE messenger, Sign, Visual, Sticker
WRITTEN CORRECTIVE FEEDBACK ON EFL STUDENTS AT AN ISLAMIC JUNIOR HIGH SCHOOL
Authors: Suharyanti Eka Mareta , Fauziati Endang
Published: August 2020

Teachers provide students with corrective feedback for guiding them in the process of teaching a language. This study aimed to investigate the types of corrective feedback that the teacher used in teaching writing recount text, this also employed to reveal the students' motivation for writing recount texts, and to explore the benefit of teacher corrective feedback to the students' ability in writing recount text at Manbaul Huda Islamic Junior High School Central Java Indonesia. Descriptive qualitative method was employed by interviewing both the teacher and the second-year students. The participants were three teachers and twenty students. There were three guided Interview questions for teachers and two questions for students. The findings of this study turned out that the teacher employed indirect corrective feedback and gave symbols to the student’s error production. Most of the students are highly motivated to be able to write a status on Facebook or other online media by using English. The most important advantage of obtaining corrective feedback for the students is to understand the use of grammar in making a sentence. This study concluded that the motivation of the students to write recount text was to get teacher corrective feedback to be able to write the appropriate sentence and to increase their ability in writing English. This also implied that different types of corrective feedback might impact differently to the students in improving their motivation to learn English more.
REFLECTIVE PRACTICE AS TOOLS TO EXPLORE IN-SERVICE TEACHERS’ BELIEFS AND CLASSROOM PRACTICES: INDONESIAN EFL TEACHERS’ VOICES
Authors: Saputra Dwi Bayu , Suherdi Didi , Rodliyah Rojab Siti
Published: August 2020

Reflective practice is widely acknowledged as the most effective means to create effective teacher who wants to have better understanding of their works. It has been explicitly stated in western academic teacher education curriculum due to its significant impact on constructing life-long learning for teachers. However, this beneficial contribution of teachers’ professional development is not growing within the context of English as a foreign Language (EFL) teaching. Accordingly, this descriptive qualitative research aimed at (1) investigating teachers’ beliefs in teaching and learning English by utilizing reflective tools, and (2) attempting to identify whether or not their beliefs are implemented in their practices in which the reasons will also be explored. The data were gathered through interviews and classroom observations as the main source. Three English teachers were investigated to elicit their beliefs about teaching and learning. The findings showed years of teaching experiences and past experiences as a learner are the most arisen theme in which the initial facet strongly affects the way they perceive teaching, and the latter occurrence theme indirectly shape the teachers’ beliefs. As regards to the relation of their practices and their stated belief, however, not all of their beliefs were implemented in the classroom due to several factors such as the students’ factors, time-constraint, and the school obligations.
THE ARGUMENT STYLE OF RESEARCH ARTICLE DISCUSSIONS BY NON-NATIVE AUTHORS OF ENGLISH PUBLISHED IN INTERNATIONAL JOURNALS
Authors: Arsyad Safnil , Zaim Muhammad , Ramadhan Syahrul , Lubis Azhar Aziz
Published: August 2020

The argument quality in the discussion section of research articles determines the quality of the article but authors often find it very difficult to write especially when writing it in a foreign language. This study is aimed at investigating how Indonesian authors in multi- disciplines as non-native speakers of English discuss their research results in their English RAs. Fifty English RAs written by Indonesian authors in multi-disciplines published in Indonesian-based journals were analysed on the ways the authors discuss their research results and justify their new knowledge claims. The results show that, like international authors, Indonesian authors in multi-disciplines consider statement of results (Move-2), reference to previous research (Move-4), explanation (Move-5), and exemplification (Move-6) conventional or obligatory. They also consider explanation of the findings (Strategy-2), illustrating or exemplifying the findings (Strategy-4), and relating the findings with those in previous studies obligatory or conventional. The implication of these findings is for teaching Indonesian young faculty members and postgraduate students in writing convincingly argumentative discussion sections when writing RAs in English for international journal publication by including necessary moves and strategies.
NUMBERED HEADS TOGETHER LEARNING STRATEGY FOR INCREASING FRESHMEN STUDENTS’ ACHIEVEMENT IN LITERATURE THEORY COURSE
Authors: Hiasa Fina , Agustina Emi
Published: August 2020

This study aims to find out how the implementation of the Numbered Heads Together (NHT) learning model in Literature Theory courses can improve the quality of learning. The subject of this research is the first semester students of class B TA 2019/2020 Indonesian Language Education Study Program FKIP Unib who are taking Literature Theory courses. Data collection techniques were carried out through questionnaires conducted in cycles I and II. It also used a test technique in the form of an oral test in cycles I and II. The study was conducted in two cycles. In the second cycle the expected learning outcomes are achieved. Learning outcomes in the second cycle showed that of 40 students there were 15 students (37.5%) who received an A. As many as 20 students with B (50%). The rest is a C value of 5 people (12.5%) and a D value of 0 people (0%). Keywords: Numbered Heads Together, Literary Theory
Radiofrequency electromagnetic field affects heart rate variability in rabbits
Authors: Misek J , Veterník M , Tonhajzerova I , Jakusova V , Janousek L , Jakus J
Published: August 2020

The aim of this study was to assess the effects of radiofrequency electromagnetic field (RF EMF) on heart rate variability (HRV) in rabbits with intensity slightly exceeding the limits for occupations. Totally 21 New Zealand white rabbits divided into two groups were used in this double-blind study. The first group of animals without general anesthesia was subjected to HRV examination under exposure to a device generated RF EMF source (frequency 1788 MHz, intensity 160 V/m, lasting 150 min.). The second group (premedications + α chloralose mg/kg) underwent the same protocol under the exposure to the real RF EMF signal from the base stations of mobile providers (frequency range 1805 – 1870 MHz - corresponding to the downlink signal of Slovak mobile providers, 160 V/m, 150 min., respectively). Individual 5 min records were used to analyze the HRV parameters: heart rate and root Mean Square of the Successive Differences (rMSSD) for time domain analysis and spectral powers in the low (LF-VFS) and high frequency (HF-VFS) bands for frequency domain analysis. Our study revealed the increased in HRV parameters (HF-HRV, rMSSD) associated with lower heart rate indicating increased cardiac vagal control under the exposure to RF EMF in experimental methods.
Thuggery, Sophisticated Impunity: Threats to Representative Democracy in Ghana
Authors: Impraim Kojo
Published: August 2020

The paper discusses patterns and dynamics of by-election violence and consequences on candidate selection in Ghana. Analysis of by-election violence as a factor of political thuggery, impunity and effects on candidate selection remain scanty on Ghanaian politics. The paper analyses the problem using nine “violent” and nine “violent-free” by-elections between 1993 and 2019, and implications on voter turnout and margin of victory between National Democratic Congress and New Patriotic Party. Voter turnout and margin of victory are low in “violent” by-election compared with “violent-free” parliamentary election in the same constituency, and “violent-free” by-elections in other constituencies. Violence is incited by foot-soldiers of the parties. I attribute by-election violence to apparent weak commitment by the government to crack the whip by linking electoral injustice and impunity to the conduct of democratic election and law maintenance. The challenge speaks to institutionalization, electoral reforms and simple majority benefiting from the entire political establishment.
Ethnic Cleansing, Genocide or Ukrainian-Polish War in Volhynia?
Authors: Katchanovski Ivan
Published: August 2020

This paper analyzes the mass murder of Poles in Volhynia in Western Ukraine during World War II. The mass murder of Poles by the Ukrainian Insurgent Army and the Bandera faction of the Organization of Ukrainian Nationalists during the Nazi occupation of Volhynia in 1943 became an important political issue in Poland and Ukraine. Previous studies by Polish, Ukrainian, and Western researchers and Ukrainian and Polish governments policies offered different and often divergent theories and narratives of this case of political violence. A research question is whether this was a Ukrainian-Polish war, ethnic cleansing or genocide. This study analyzes a variety of archival documents, historical studies, and eyewitness accounts. It concludes that the mass murder of the Polish minority in Volhynia by the OUN-B, the UPA, and their security service (SB) represented not a Ukrainian-Polish war or genocide of Poles but that it was a part of ethnic cleansing.
Political Marketing, Tribal Marketing, & the Two-Way Flow of Influence
Authors: Vodrey Simon
Published: August 2020

Political marketing holds that marketing has penetrated nearly all aspects of politics and that political marketers superimpose the strategies and tactics of commercial marketers onto politics. While this pattern of influence has dominated the literature, I examine the extent to which the flow of influence and innovation between commercial and political marketers may be functioning as a feedback loop. The example I use to investigate this is tribal marketing. My analysis proceeds accordingly: First, I establish the basics of tribal marketing. Second, relying upon the results from thirty-three (33) in-depth elite interviews with political marketers, market researchers, political researchers, pollsters and commercial marketers from Canada, the United States, and New Zealand, I examine how tribal marketing is becoming a more recognizable and effective way of marketing and how political marketers, being more familiar with this practice, are better at building and mobilizing tribes than are commercial marketers.
The Politics of Fiscal Federalism: Building a Stronger Decentralization Theorem
Authors: Ponce-Rodríguez Raúl , Hankla Charles R. , Martinez-Vazquez Jorge , Heredia-Ortiz Eunice
Published: August 2020

We explore how party structures can condition the benefits of decentralization in modern democracies. In particular, we study the interaction of two political institutions: democratic (de)centralization (whether a country has fiscally autonomous and elected local governments) and party (non)integration (whether power over local party leaders flows upwards through party institutions, which we model using control over candidate selection). We incorporate these institutions into our strong decentralization theorem, which expands on Oates (1972) to examine when the decentralized provision of public services will dominate centralized provision even in the presence of inter-jurisdictional spillovers. Our findings suggest that, when externalities are present, democratic decentralization will be beneficial only when parties are integrated. In countries with non-integrated parties, we find that the participation rules of primaries have implications for the expected gains from democratic decentralization.
Exploring Carbon Mineral Systems: Recent Advances in C Mineral Evolution, Mineral Ecology, and Network Analysis
Authors: Morrison Shaunna M. , Buongiorno Joy , Downs Robert T. , Eleish Ahmed , Fox Peter , Giovannelli Donato , Golden Joshua J. , Hummer Daniel R. , Hystad Grethe , Kellogg Louise H. , Kreylos Oliver , Krivovichev Sergey V. , Liu Chao , Merdith Andrew , Prabhu Anirudh , Ralph Jolyon , Runyon Simone E. , Zahirovic Sabin , Hazen Robert M.
Published: August 2020

Large and growing data resources on the spatial and temporal diversity and distribution of the more than 400 carbon-bearing mineral species reveal patterns of mineral evolution and ecology. Recent advances in analytical and visualization techniques leverage these data and are propelling mineralogy from a largely descriptive field into one of prediction within complex, integrated, multidimensional systems. These discoveries include: (1) systematic changes in the character of carbon minerals and their networks of coexisting species through deep time; (2) improved statistical predictions of the number and types of carbon minerals that occur on Earth but are yet to be discovered and described; and (3) a range of proposed and ongoing studies related to the quantification of network structures and trends, relation of mineral “natural kinds” to their genetic environments, prediction of the location of mineral species across the globe, examination of the tectonic drivers of mineralization through deep time, quantification of preservational and sampling bias in the mineralogical record, and characterization of feedback relationships between minerals and geochemical environments with microbial populations. These aspects of Earth’s carbon mineralogy underscore the complex co-evolution of the geosphere and biosphere and highlight the possibility for scientific discovery in Earth and planetary systems.
T Cell Responses to Neural Autoantigens Are Similar in Alzheimer’s Disease Patients and Age-Matched Healthy Controls
Authors: Dhanwani Rekha , Pham John , Premlal Ashmitaa Logandha Ramamoorthy , Frazier April , Kumar Atul , Pero Maria Elena , Bartolini Francesca , Dutra Juliana Rezende , Marder Karen S. , Peters Bjoern , Sulzer David , Sette Alessandro , Lindestam Arlehamn Cecilia S.
Published: August 2020

Alzheimer’s disease (AD), a chronic multifactorial and complex neurodegenerative disorder is a leading cause of dementia. Recently, neuroinflammation has been hypothesized as a contributing factor to AD pathogenesis. The role of adaptive immune responses against neuronal antigens, which can either confer protection or induce damage in AD, has not been fully characterized. Here, we measured T cell responses to several potential antigens of neural origin including amyloid precursor protein (APP), amyloid beta (Aβ), tau, α-synuclein, and transactive response DNA binding protein (TDP-43) in patients with AD and age-matched healthy controls (HC). Antigen-specific T cell reactivity was detected for all tested antigens, and response to tau-derived epitopes was particularly strong, but no significant differences between individuals with AD and age-matched HC were identified. We also did not observe any correlation between the antigen-specific T cell responses and clinical variables including age, gender, years since diagnosis and cognitive score. Additionally, further characterization did not reveal any differences in the relative frequency of major Peripheral Blood Mononuclear Cells (PBMC) subsets, or in the expression of genes between AD patients and HC. These observations have not identified a key role of neuronal antigen-specific T cell responses in AD.
Polyphenols by Generating H2O2, Affect Cell Redox Signaling, Inhibit PTPs and Activate Nrf2 Axis for Adaptation and Cell Surviving: In Vitro, In Vivo and Human Health
Authors: Kanner Joseph
Published: August 2020

Human health benefits from different polyphenols molecules consumption in the diet, derived mainly by their common activities in the gastrointestinal tract and at the level of blood micro-capillary. In the stomach, intestine and colon, polyphenols act as reducing agents preventing lipid peroxidation, generation and absorption of AGEs/ALEs (advanced glycation end products/advanced lipid oxidation end products) and postprandial oxidative stress. The low absorption of polyphenols in blood does not support their activity as antioxidants and their mechanism of activity is not fully understood. The results are from in vitro, animal and human studies, detected by relevant oxidative stress markers. The review carries evidences that polyphenols, by generating H2O2 at nM concentration, exogenous to cells and organs, act as activators of signaling factors increasing cell Eustress. When polyphenols attain high concentration in the blood system, they generate H2O2 at µM concentration, acting as cytotoxic agents and Distress. Pre-treatment of cells or organisms with polyphenols, by generating H2O2 at low levels, inhibits cellular PTPs (protein tyrosine phosphatases), inducing cell signaling through transcription of the Nrf2 (nuclear factor erythroid 2-related factor 2) axis of adaptation and protection to oxidation stress. Polyphenols ingestion at the right amount and time during the meal acts synergistically at the level of the gastrointestinal tract (GIT) and blood system, for keeping the redox homeostasis in our organism and better balancing human health.
Keyword Search over RDF: Is a Single Perspective Enough?
Authors: Nikas Christos , Kadilierakis Giorgos , Fafalios Pavlos , Tzitzikas Yannis
Published: August 2020

Since the task of accessing RDF datasets through structured query languages like SPARQL is rather demanding for ordinary users, there are various approaches that attempt to exploit the simpler and widely used keyword-based search paradigm. However this task is challenging since there is no clear unit of retrieval and presentation, the user information needs are in most cases not clearly formulated, the underlying RDF datasets are in most cases incomplete, and there is not a single presentation method appropriate for all kinds of information needs. As a means to alleviate these problems, in this paper we investigate an interaction approach that offers multiple presentation methods of the search results (multiple-perspectives), allowing the user to easily switch between these perspectives and thus exploit the added value that each such perspective offers. We focus on a set of fundamental perspectives, we discuss the benefits from each one, we compare this approach with related existing systems and report the results of a task-based evaluation with users. The key finding of the task-based evaluation is that users not familiar with RDF (a) managed to complete the information-seeking tasks (with performance very close to that of the experienced users), and (b) they rated positively the approach.
Determining the Optimal Number of Ground Control Points for Varying Study Sites through Accuracy Evaluation of Unmanned Aerial System-Based 3D Point Clouds and Digital Surface Models
Authors: Yu Jae Jin , Kim Dong Woo , Lee Eun Jung , Son Seung Woo
Published: August 2020

The rapid development of drone technologies, such as unmanned aerial systems (UASs) and unmanned aerial vehicles (UAVs), has led to the widespread application of three-dimensional (3D) point clouds and digital surface models (DSMs). Due to the number of UAS technology applications across many fields, studies on the verification of the accuracy of image processing results have increased. In previous studies, the optimal number of ground control points (GCPs) was determined for a specific area of a study site by increasing or decreasing the amount of GCPs. However, these studies were mainly conducted in a single study site, and the results were not compared with those from various study sites. In this study, to determine the optimal number of GCPs for modeling multiple areas, the accuracy of 3D point clouds and DSMs were analyzed in three study sites with different areas according to the number of GCPs. The results showed that the optimal number of GCPs was 12 for small and medium sites (7 and 39 ha) and 18 for the large sites (342 ha) based on the overall accuracy. If these results are used for UAV image processing in the future, accurate modeling will be possible with minimal effort in GCPs.
Function Estimation in Inverse Heat Transfer Problems Based on Parameter Estimation Approach
Authors: Mohebbi Farzad
Published: August 2020

A new sensitivity analysis scheme is presented based on explicit expressions for sensitivity coefficients to estimate timewise varying heat flux in heat conduction problems over irregular geometries using the transient readings of a single sensor. There is no prior information available on the functional form of the unknown heat flux; hence, the inverse problem is regarded as a function estimation problem and sensitivity and adjoint problems are involved in the solution of the inverse problem to recover the unknown heat flux. However, using the proposed sensitivity analysis scheme, one can compute all sensitivity coefficients explicitly in only one direct problem solution at each iteration without the need for solving the sensitivity and adjoint problems. In other words, the functional form of the unknown heat flux can be numerically estimated by using the parameter estimation approach. In this method, the irregular shape of heat-conducting body is meshed using the boundary-fitted grid generation (elliptic) method. Explicit expressions are given to compute the sensitivity coefficients efficiently and the steepest-descent method is used as the minimization method to minimize the objective function and reach the solution. Three test cases are presented to confirm the accuracy and efficiency of the proposed inverse analysis.
Impact of the DFIG-Based Wind Farm Connection on the Fault Component-Based Directional Relay and a Mitigation Countermeasure
Authors: Li Xu , Lu Yuping , Huang Tao
Published: August 2020

With high sensitivity and strong tolerance capability for the fault resistance, the fault component-based directional relay (FCBDR) has drawn considerable attention from industry and academia. However, the best application environment for FCBDR no longer exists when considering the large-scale connection of the doubly fed induction generator (DFIG)-based wind farms. Through a detailed analysis of the superimposed impedance of DFIG, this paper reveals that the performances of FCBDRs may be shown negatively impacted by the fault behaviors of DFIG when the crowbar protection inputs. In addition, this paper proposes a mitigation countermeasure to deal with those issues. The proposed countermeasure takes advantage of the different superimposed impedance features of DFIG compared with that of the synchronous generator (SG) to enhance the adaptability of the conventional FCBDRs. Extensive simulation results show that the proposed countermeasure can differentiate the fault direction clearly under different fault conditions.
Research on Synchronverter-Based Regenerative Braking Energy Feedback System of Urban Rail Transit
Authors: Li Shuting , Wu Songrong , Xiang Shiqiang , Zhang Yabo , Guerrero Josep M. , Vasquez Juan C.
Published: August 2020

Generally running with frequent braking over short distances, the urban rail transit train generates great quantities of regenerative braking energy (RBE). The RBE feedback system can effectively recycle RBE and give it back to the AC grid. However, the lack of damp and inertia of generators makes conventional PWM RBE feedback system more sensitive to power fluctuations. To address this issue, a synchronverter-based RBE feedback system of urban rail transit is designed in this paper. First, the structure of the feedback system is presented. Then, the synchronverter-based control strategy with greater flexibility and higher stability is fully discussed. Furthermore, the parameter design of the system is analyzed in detail. Finally, simulation results and experimental results are provided to show the good dynamic performance of the system. Using this synchronverter-based approach, the system supplies traction power to the traction network when the train accelerates and gives the RBE back to the AC grid when the train brakes, in light of the variation of the DC bus voltage. Moreover, the system can be self-synchronized with the AC grid and make corresponding power management on the basis of changes in the voltage amplitude as well as the frequency of the grid. In this sense, the RBE feedback system becomes more flexible, effective and robust.
Study on the Effects of Microstructural Surfaces on the Attachment of Moving Microbes
Authors: Yang Hongyue , Qian Ji , Yang Ming , Li Chunxi , Li Hengfan , Wang Songling
Published: August 2020

The research of marine antifouling is mainly conducted from the aspects of chemistry, physics, and biology. In the present work, the movement model of microorganisms along or against the flow direction on the microstructural surface was established. The model of globose algae with a diameter of 5 μm in the near-wall area was simulated by computational fluid dynamics (CFD), and the fluid kinematic characteristics and shear stress distribution over different-sized microstructures and in micropits were compared. Simulation results revealed that the increase of the β value (height to width ratio) was prone to cause vortexes in micropits. In addition, the closer the low-velocity region of the vortex center to the microstructural surface, the more easily the upper fluid of the microstructure slipped in the vortex flow and reduced the microbial attachment. Moreover, the shear stress in the micropit with a height and width of 2 μm was significantly higher than those in others; thus, microbes in this micropit easily fell off.
Thermal Bridge Modeling and a Dynamic Analysis Method Using the Analogy of a Steady-State Thermal Bridge Analysis and System Identification Process for Building Energy Simulation: Methodology and Validation
Authors: Kim Heegang , Yeo Myoungsouk
Published: August 2020

It is challenging to apply heat flow through a thermal bridge, which requires the analysis of 2D or 3D heat transfer to building energy simulation (BES). Research on the dynamic analysis of thermal bridges has been underway for many years, but their utilization remains low in BESs. This paper proposes a thermal bridge modeling and a dynamic analysis method that can be easily applied to BESs. The main idea begins with an analogy of the steady-state analysis of thermal bridges. As with steady-state analysis, the proposed method first divides the thermal bridge into a clear wall, where the heat flow is uniform, and the sections that are not the clear wall (the thermal bridge part). For the clear wall part, the method used in existing BESs is applied and analyzed. The thermal bridge part (TB part) is modeled with the linear time-invariant system (LTI system) and the system identification process is performed to find the transfer function. Then, the heat flow is obtained via a linear combination of the two parts. This method is validated by comparing the step, sinusoidal and annual outdoor temperature response of the finite differential method (FDM) simulation. When the thermal bridge was modeled as a third-order model, the root mean square error (RMSE) of annual heat flow with the FDM solution of heat flow through the entire wall was about 0.1 W.
The Combustion of Methane from Hard Coal Seams in Gas Engines as a Technology Leading to Reducing Greenhouse Gas Emissions—Electricity Prediction Using ANN
Authors: Borowski Marek , Życzkowski Piotr , Cheng Jianwei , Łuczak Rafał , Zwolińska Klaudia
Published: August 2020

Greenhouse gases such as carbon dioxide and methane cause global warming and consequently climate change. Great efforts are being made to reduce greenhouse gas emissions with the objective of addressing this problem, hence the popularity of technologies conductive to reducing greenhouse gas emissions. CO2 emissions can be reduced by improving the thermal efficiency of combustion engines, for example, by using cogeneration systems. Coal mine methane (CMM) emerges due to mining activities as methane released from the coal and surrounding rock strata. The amount of methane produced is primarily influenced by the productivity of the coal mine and the gassiness of the coal seam. The gassiness of the formation around the coal seam and geological conditions are also important. Methane can be extracted to the surface using methane drainage installations and along with ventilation air. The large amounts of methane captured by methane drainage installations can be used for energy production. This article presents a quarterly summary of the hourly values of methane capture, its concentration in the methane–air mixture, and electricity production in the cogeneration system for electricity and heat production. On this basis, neural network models have been proposed in order to predict electricity production based on known values of methane capture, its concentration, pressure, and parameters determining the time and day of the week. A prediction model has been established on the basis of a multilayer perceptron network (MLP).
A Modified Reynolds-Averaged Navier–Stokes-Based Wind Turbine Wake Model Considering Correction Modules
Authors: Li Yuan , Xu Zengjin , Xing Zuoxia , Zhou Bowen , Cui Haoqian , Liu Bowen , Hu Bo
Published: August 2020

Increasing wind power generation has been introduced into power systems to meet the renewable energy targets in power generation. The output efficiency and output power stability are of great importance for wind turbines to be integrated into power systems. The wake effect influences the power generation efficiency and stability of wind turbines. However, few studies consider comprehensive corrections in an aerodynamic model and a turbulence model, which challenges the calculation accuracy of the velocity field and turbulence field in the wind turbine wake model, thus affecting wind power integration into power systems. To tackle this challenge, this paper proposes a modified Reynolds-averaged Navier–Stokes (MRANS)-based wind turbine wake model to simulate the wake effects. Our main aim is to add correction modules in a 3D aerodynamic model and a shear-stress transport (SST) k-ω turbulence model, which are converted into a volume source term and a Reynolds stress term for the MRANS-based wake model, respectively. A correction module including blade tip loss, hub loss, and attack angle deviation is considered in the 3D aerodynamic model, which is established by blade element momentum aerodynamic theory and an improved Cauchy fuzzy distribution. Meanwhile, another correction module, including a hold source term, regulating parameters and reducing the dissipation term, is added into the SST k-ω turbulence model. Furthermore, a structured hexahedron mesh with variable size is developed to significantly improve computational efficiency and make results smoother. Simulation results of the velocity field and turbulent field with the proposed approach are consistent with the data of real wind turbines, which verifies the effectiveness of the proposed approach. The variation law of the expansion effect and the double-hump effect are also given.
A Wide-Adjustable Sensorless IPMSM Speed Drive Based on Current Deviation Detection under Space-Vector Modulation
Authors: Mubarok Muhammad Syahril , Liu Tian-Hua , Tsai Chung-Yuan , Wei Zuo-Ying
Published: August 2020

This paper investigates the implementation of a wide-adjustable sensorless interior permanent magnet synchronous motor drive based on current deviation detection under space-vector modulation. A hybrid method that includes a zero voltage vector current deviation and an active voltage vector current deviation under space-vector pulse-width modulation is proposed to determine the rotor position. In addition, the linear transition algorithm between the two current deviation methods is investigated to obtain smooth speed responses at various operational ranges, including at a standstill and at different operating speeds, from 0 to 3000 rpm. A predictive speed-loop controller is proposed to improve the transient, load disturbance, and tracking responses for the sensorless interior permanent magnet synchronous motor (IPMSM) drive system. The computations of the position estimator and control algorithms are implemented by using a digital signal processor (DSP), TMS-320F-2808. Several experimental results are provided to validate the theoretical analysis.
Technical Approaches and Institutional Alignment to 100% Renewable Energy System Transition of Madeira Island—Electrification, Smart Energy and the Required Flexible Market Conditions
Authors: Marczinkowski Hannah Mareike , Barros Luísa
Published: August 2020

The integration of renewable energy (RE) in energy systems can be approached in many ways depending on local possibilities. Evaluating this in the limited context of islands, this paper presents a multi-energy system transition to a 100% RE share in a two-folded technical analysis. The case study of Madeira Island using the EnergyPLAN modeling tool is used to show strengths and weaknesses of, on the one hand, electrifying all transport and heating demands on an island, while remaining demands are supplied with biomass, and, on the other hand, additional smart charging, vehicle-to-grid, thermal collectors and storages, as well as electrofuel production and storages. Technical results indicate the potentials and advantages of the second approach with 50% less biomass and no curtailment at 1–3% higher costs, compared to the first one with 7% of production curtailed. The technical analysis is supported by the institutional analysis that highlights the balancing needs through additional flexibility and interaction in the energy system. For maximum flexibility, of both demand and grid, and successful implementation of 100% RE, investment incentives and dynamic tariffs are recommended entailing more dynamic consumer involvement and strategic energy planning.
Analysis of Standby Losses and Charging Cycles in Flywheel Energy Storage Systems
Authors: Amiryar Mustafa E. , Pullen Keith R.
Published: August 2020

Aerodynamic drag and bearing friction are the main sources of standby losses in the flywheel rotor part of a flywheel energy storage system (FESS). Although these losses are typically small in a well-designed system, the energy losses can become significant due to the continuous operation of the flywheel over time. For aerodynamic drag, commonly known as windage, there is scarcity of information available for loss estimation since most of the publications do not cover the partial vacuum conditions as required in the design of low loss energy storage flywheels. These conditions cause the flow regime to fall between continuum and molecular flow. Bearings may be of mechanical or magnetic type and in this paper the former is considered, typically hybridized with a passive magnetic thrust bearing. Mechanical bearing loss calculations have been extensively addressed in the open literature, including technical information from manufacturers but this has not previously been presented clearly and simply with reference to this application. The purpose of this paper is therefore to provide a loss assessment methodology for flywheel windage losses and bearing friction losses using the latest available information. An assessment of windage losses based on various flow regimes is presented with two different methods for calculation of windage losses in FESS under rarefied vacuum conditions discussed and compared. The findings of the research show that both methods closely correlate with each other for vacuum conditions typically required for flywheels. The effect of the air gap between the flywheel rotor and containment is also considered and justified for both calculation methods. Estimation of the bearing losses and considerations for selection of a low maintenance, soft mounted, bearing system is also discussed and analysed for a flywheel of realistic dimensions. The effect of the number of charging cycles on the relative importance of flywheel standby losses has also been investigated and the system total losses and efficiency have been calculated accordingly.