bluuebunny/crossref_metadata_2025 huggingface dataset:
Sentiment Analysis of Community Opinion on Online Store in Indonesia on Twitter using Support Vector Machine Algorithm (SVM)
Authors: Syahputra H
Published: March 2021

Public opinion on the Online Shop service company in Indonesia can be seen through comments sent via tweeter. The purpose of this study is to see the public opinion sentiment towards online stores in Indonesia via Twitter using the Support Vector Machine algorithm. Public opinion and assessment on Twitter can be classified into 3 classes, namely negative, neutral, and positive. The approach used is Multiclass One Vs Rest SVM by using Kernel Sigmoid, Linear, and RBF to classify public tweets about Indonesian Online Shop services, namely Shopee, Tokopedia, Bukalapak, and JDid. The results obtained are the Multiclass (One Vs Rest) Support Vector Machine kernel algorithm which has the best accuracy is the Sigmoid kernel with 82% accuracy on the Shopee online store dataset, 94.7% on the Tokopedia dataset and 75.3% for the Bukalapak dataset, while the Linear kernel Jdid dataset provides better accuracy, namely 78%. Clarification errors can occur due to overfiting, namely the model adjusts the training data very well (accuracy can reach 100%) so that the model cannot generalize well on the testing data.
The Effectiveness of Research Based in Vitro Textbook Application in Contextual Learning on Scientific Attitudes Mastery of Biology Students
Authors: Sugiati Eka , Harahap Fauziyah , Idramsa
Published: March 2021

This research aims to determine the effectiveness of research-based in vitro textbooks in achieving students’ learning outcomes on scientific attitudes mastery. The population of the study was 74 students of undergraduate Biology study program Semester VI academic year 2019/2020 of Universitas Negeri Medan. The Sample was taken by using perposive sampling technique where the classses were grouped in a control class and an experimental class. The experimental class was given treatment by using research-based textbook while the control class used the textbook which was not research-based. The design of the study used Pretest-Posttest Control Group Design. The research instruments used was a questionnaire. To test the hypothesis the reseacher used t-test. The result showed that the mean of posttest from control class was 81,528 on scientific attitude mastery while the posttest mean of experimental class was 91,026. The t-test in the experimental class showed that tcount was 5,413> t table 2,02809 on scientific attitude mastery. Thus the group of students which was given treatment using research-based textbooks had a higher mean score than the group of students without using research-based textbooks.
Biodiversity Arbuscular Mycorrhizal Fungi in the Former Gold Mine Area in North Sumatra
Authors: Pulungan Ahmad Shafwan S , Nasution Mhd. Yusuf
Published: March 2021

This study aims to determine the diversity of arbuscular mycorrhizal fungi in the area of the former gold mine in North Sumatra. This research was conducted with 5 soil sampling points. The research method used began with calculating the percentage of root colonization, spores density of arbuscular mycorrhizal fungi and types of arbuscular mycorrhizal fungal spores. In addition, physical and chemical conditions of the soil are also measured. The results showed that the rate of root colonization was at moderate to high with an average rate of root colonization at 22.8%. The density of arbuscular mycorrhizal fungi spores in this study averaged 10/50 g of sample soil. the number of spores in this study belongs to the moderate category, however the characteristics of the study location show the uniqueness of its own area that makes the population of mycorrhizal types not too much. Spore types were found in 4 types with each Glomus and Acaulospora. The conclusion obtained that there was a symbiosis between fungi and plants in the former gold mining area in North Sumatra.
Development of Digital Book in Enhancing Students’ Higher-Order Thinking Skill
Authors: Siregar Budi Halomoan , Kairuddin  , Mansyur Abil , Siregar Nurhasanah
Published: March 2021

During the Covid-19 pandemic, the learning process is carried out massively from home, on the other hand, higher-order thinking skills (HOTS) remain a priority for learning objectives, therefore it is necessary to ensure creative solutions to achieve it. Digital book is a learning media that is compiled by combining: 1) text, 2) animation, 3) audio, 4) video, which can be accessed easily and systematically via online. The development of this book aims to facilitate online learning during the covid-19 pandemic, then specifically to measure the level of validity, practically, and effectiveness in increasing students’ HOTS. This research was conducted in five stages: 1) analyzing, 2) designing, 3) development, 4) implementation, and 5) evaluation (ADDIE model), while the instruments used were observation sheets, validation sheets, questionnaires, and essay tests. This research was conducted in class E and F, each consist of 35 students. The results of data analysis indicate that this book is in a valid and practical category. Furthermore, this book is very effective to be used to enhance student HOTS.
Designing Interactive Videos in Online Multivariable Calculus Course to Support Student’s Critical Thinking
Authors: Firdaus M , Mukhtar  , Darari M B , Azis Z
Published: March 2021

Emphasizing critical thinking skills in the curriculum of higher education institutions is needed to produce graduates with higher order thinking skills. Given the importance of information technology for critical thinking in learning, it is necessary to understand the key factors related to learning designs that utilize information technology in their learning environment and consider the pedagogical and information technology alignment. This study aims to describe the process of analysing, designing, and developing interactive learning videos as part of the redesign of the multivariable calculus course to support students’ critical thinking skills. This paper will describe the lessons learned from and the next steps in this research and development process.
Development of a Field Guide Book on the Pteridophyta Topic in Padang Lawas Regency
Authors: Siregar Saddam Hamidi
Published: March 2021

This study aimed to determine the feasibility of a field manual guidance for ferns (Pteridophyta) in oil palm and rubber plantations in Padang Lawas District. The subjects in this study were (1) material experts, (2) instructional design experts, (3) layout design experts and (4) 4th semester undergraduate students of Biology Department at Universitas Negeri Medan. This field manual guidance was developed according to Thiagarajan (4D), namely the stages: define, design, development and dissemination, but in this study it was only up to the development stage. The results showed that (1) the assessment of material experts based on material suitability, accuracy and strength of the material, learning systematics, efficiency of field manual guidance in learning and language had an average score of 79.5% with good criteria, (2) the assessment of instructional design experts based on the feasibility and presentation of the content had an average score of 90.86% with very good criteria, (3) the assessment of the layout design experts based on the size aspect, the cover design and the content design of the field manual guidance had an average score namely 82.87% with very good criteria, (4) assessment by 4th semester undergraduate students based on individual trials, small groups and limited groups sequentially had scores 84.04%, 93.63%, 86.86% which showed very good criteria. Therefore it can be concluded that the field guide book for ferns (Pteridophyta) in oil palm and rubber plantations in Padang Lawas Regency which was developed was feasible according to material experts, instructional design experts, layout design experts and students, so that the field manual guidance for ferns (Pteridophyta) in oil palm and rubber plantations in Padang Lawas District could be used as a supplementary book for lecturers, students, readers in general and researchers interested in the field of ferns (Pteridophyta).
Isolation of Nematophagous Fungi from Lau Kawar Lake, North Sumatra, Indonesia
Authors: Hastuti L D S , Yurnaliza Y , Tarigan W E , Hartanto A , Pahlevi S
Published: March 2021

Root-knot nematodes are harmful organisms which cause severe damage to plants and decreasing its productivity. Biocontrol agents isolated from potential environment may solve the intriguing problem of these nematodes. Nematophagous fungi has proven as promising strategy in controlling nematodes when compared to commercial pesticides which may pollute the soil and environment through accumulated residues post-usage. Nematophagous fungi were isolated from several soils or sediments around Lau Kawar Lake using a combination of pour and sprinkle techniques. Nine fungal morphotypes were recovered from soil/sediment samples as revealed from their distinctive morphologies. Two isolates, LK.10.1 and LK.10.3 were designated as potential nematophagous fungal isolates by their effectiveness in killing nematodes within 36 hr of observation. Species-level identification is currently carried out for the isolates to reveal and confirm their identities as nematophagous fungi.
Online Learning in Faculty of Mathematics and Natural Sciences, State University of Medan: Lecturers’ Preferences for Online Learning Media During the Covid-19 Pandemic
Authors: Sipahutar Herbert , Harahap Fauziyah , Mukhtar  , Nasution Muh. Yusuf
Published: March 2021

Online learning has long been promoted by the Faculty of Mathematics and Natural Sciences (FMNS), State University of Medan (SUM). The online learning system (SIPDA) has been developed by Unimed as the backbone of online learning, but the number of lecturers using the system has not been as expected. The covid-19 has succeeded in forcing all lecturers to migrate from classroom face-to-face (offline) to online learning. This research was aimed to study the preferences of lecturers for available online learning media during the Covid-19 pandemic. The data were obtained using questionnaire that distributed online to all lecturers and students who were active in lectures for the even semester of the 2019/2020 academic year. The data shows that all lecturers have implemented online learning to serve all classes. The majority of lecturers serve their class by using more than one online media. The order of the three types of online media which became the main preference of lecturers experienced a shift during the 3 months of observation, namely from WhatsApp (WA) - Email - Google Classroom (GC) in the first, to WA - GC - SIPDA in the second, and to WA - SIPDA - GC in the third month. It can be concluded that, although initially the lecturers’ main preference in learning was social media (WA), they have tried hard to make SIPDA as the main choice among the available e-learning media.
Multi-face Recognition for the Detection of Prisoners in Jail using a Modified Cascade Classifier and CNN
Authors: Diyasa G S M , Fauzi A , Idhom M , Setiawan A
Published: March 2021

Identifying the identity of a prisoner in a detention cell, through facial recognition automatically is a big, exciting problem and there are many different approaches to solve this problem because it must detect multiple faces (multi-face). Especially in uncontrolled real-life scenarios, faces will be seen from various sides and not always facing forward, which makes classification problems more difficult to solve. In this research, one method is combined deep neural networks that is Convolutional Neural Networks (CNN) and Haar Cascade Classifier as real-time facial recognition, which has proven to be very efficient in face classification. Methods are implemented with assistance library Open-CV for multi-face detection and 5MP CCTV camera devices. In preparing the architectural model Convolutional Neural Networks Do configuration parameter initialization to speed up the network training process. Test results on 51 test data using constructs Convolutional Neural Networks VGG16 models up to a depth of 16 layers of convolution layers with input from the extraction of the Haar Cascade Classifier resulting in facial recognition system performance reaching an accuracy rate of about 87%.
Single Phase Inverter with Power Monitoring using Arduino
Authors: Maghfiroh H , Affandy J T , Adriyanto F , Nizam M
Published: March 2021

The inverter is an electronic device which able to convert DC electricity into AC electricity. In the development of renewable energy resources, for example, solar power plants, inverters are needed. In this research, an inverter is made by real-time power monitoring. The inverter is made using unipolar PWM modulation and a full H bridge topology. PWM signals are generated from Arduino microcontrollers that will control MOSFET switching. Power monitoring is done by installing a DC voltage sensor and INA219 DC current sensor while on the output side using the PZEM 004t (v3) sensor and results will be displayed on the OLED. The experiment was successfully carried out by producing an approaching sine wave signal with a frequency of 50 Hz and 220 V AC voltage. The efficiency of the inverter is low because of loss from the transformer which has a no-load efficiency of 68.7%. When the 15W load has installed the efficiency of the inverter is 31.83% and when the 20W load has installed the efficiency of the inverter is 34.72%. Finally, when the smartphone’s charger is installed the total efficiency was 49.96%.
Monitoring of Hydrogen Fuel Cell Modeling with Boost Converter
Authors: Mubarok Husein , Santoso Tegar Hery
Published: March 2021

Energy plays a very important role in human life. Every year, the demand for energy needs continues to increase and the majority of energy generation uses fossil fuels. So we need an energy source that is environmentally friendly. One of the environmentally friendly energy sources is a fuel cell. Fuel cells can produce electrical energy at a lower cost than the electrical energy generated by conventional power grids. In making a fuel cell system, a modeling is needed so that the fuel cell system can work properly and in accordance with the desired specifications. One method for modeling a fuel cell system is to use MATLAB. The use of a DC-DC boost converter with a properly designed closed loop PID controller has a very important role in regulating the PWM of the DC-DC boost converter switch and plays a very important role in controlling power regulation. In this research, a modeling analysis of NEXATM 1.2 kW hydrogen fuel cell with a DC-DC boost converter controlled by a PID controller was carried out for a compact Power Conditioning Unit (PCU) design. The purpose of this research is to model and analyze the characteristics of the performance of the hydrogen fuel cell system and the performance of the PID controller in regulating the DC-DC boost converter output voltage on the hydrogen fuel cell. The results showed that the performance of the hydrogen fuel cell was influenced by the pressure of oxygen gas, hydrogen, and temperature. The greater the value of oxygen gas pressure, hydrogen gas pressure, and temperature on the fuel cell, the greater the voltage and current output of the fuel cell. The simulation results show the fuel cell output voltage is 47.89 V with an error percentage of 4.22%, and the fuel cell output current is 23.94 A with an error percentage of 0.25%, and the fuel cell output power is 1147 W with an error percentage of 4.12%. The performance of the PID controller with the DC-DC boost converter in regulating the fuel cell output voltage is very good. This is indicated by the results of the response curve for the fuel cell output current, namely the value of rise time (tr) of 4 seconds, delay time (td) of 0.2 seconds, peak time (tp) of 4 seconds, settling time (ts) of 4 seconds, and a maximum overshoot (Mp) of 0%. For output voltage, the value of rise time (tr) is 4 seconds, delay time (td) is 0.2 seconds, peak time (tp) is 4 seconds, settling time (ts) is 4 seconds, and maximum overshoot (Mp) is 0% with the parameter value Proportional (P) of 0.001, Integral (I) of 10, and Derivative (D) of 0.
Fractal Based Feature Extraction Method for Epileptic Seizure Detection in Long-Term EEG Recording
Authors: Humairani A , Atmojo B S , Wijayanto I , Hadiyoso S
Published: March 2021

One of the most common brain disorders is epilepsy. A person who has epilepsy is not able to have normal days like the others. It’s characterized by more than two unprovoked seizures. However, the faster detection and treatment of epileptic seizures, the quicker reduction of the disease abnormal level. Neurologists are still diagnosing, detecting, and testing a seizure manually by observing the Electroencephalogram (EEG) signals. This takes a very long time because of the irregularity of EEG signals. Hence, a Computer-Aided Diagnosis (CAD) is developed by many scientists to help neurologists in detecting seizures automatically. In this research, a CAD system was developed at CHB-MIT dataset. The EEG signals were processed at several stages through this system, namely pre-processing, decomposition, feature extraction, and classification. In pre-processing, the EEG signals were uniformed by selecting the most appropriate channels and filtered using Butterworth Bandpass Filter (BPF) to remove noise. The process continued to the decomposition and feature extraction stage using Empirical Mode Decomposition (EMD) and fractal dimension-based methods, i.e. Higuchi, Katz, and Sevcik, respectively. Then, the features were classified by Support Vector Machine (SVM). The proposed method achieved the highest accuracy at 94.72% on the Chb07 record. Meanwhile, the average accuracy was 81.2% for all records. The proposed study is expected to be applied for the detection of seizure onset in a real-time system.
Optimization of design parameters for SPPC longitudinal dynamics
Authors: Zhang L.H. , Tang J.Y. , Hong Y. , Chen Y.K. , Wang L.J.
Published: March 2021

As the second stage of the CEPC-SPPC project, SPPC (Super Proton-Proton Collider) aims at exploring new physics beyond the Standard Model. The key design goal for the SPPC accelerator complex is to reach 75 TeV in center of mass energy with a circumference of 100 km for the collider and an injector chain of four accelerators in cascade to support the collider. As an important part of the SPPC conceptual study, the longitudinal beam dynamics was studied systematically, which includes the dynamics in the collider and its complex injector chain. First, the bunch filling scheme of the SPPC complex was designed on the basis of various constraints such as the technical challenges of the kicker magnets, limited extraction energy per injection and so on. Next, the study on the longitudinal dynamics in the collider focused on the RF scheme to meet the requirements for luminosity and mitigate relevant instabilities. A higher harmonic RF system (800 MHz) together with the basic RF system (400 MHz) to form a dual-harmonic RF system was employed to mitigate collective instabilities and increase the luminosity by producing shorter bunches. In addition, the longitudinal matchings between the bunches in the different accelerator stages were studied, with special attention to the space charge effects and the beam loading effect in the two lower energy rings (p-RCS and MSS), which result in an optimization of the RF schemes. A set of self-consistent beam and RF parameters for the SPPC complex was obtained. The collider and the three proton synchrotrons of the injector chain have unprecedented features, thus this study demonstrates how a future proton-proton collider complex looks like.
Mathematical analysis and experimental testing of floating building platform prototypes made from expanded polystyrene system (Styrofoam) and lightweight concrete
Authors: Handayani Fitri , Adi Henny Pratiwi , Wahyudi Slamet Imam
Published: March 2021

Floating building is one of the solutions to anticipate residential areas against Tidal floods which have been occurring on the North Coast of Central Java. This floating building can adjust its buoyancy to the effect of rising sea level and land subsidence. This building can be applied in sea tidal flood areas and retention ponds in polder systems. The main materials used as the floating building platform are styrofoam and lightweight concrete. This study aims to determine the stability, capacity and buoyancy of the prototype platform using styrofoam and lightweight concrete. This study uses mathematical analysis methods and prototype testing with laboratory experiments. Based on the analysis result for the styrofoam material platform with dimensions of 2 × 2 × 0.62 m, a buoyancy force of 2.73 tons was obtained with the Safety Factor (SF) of 1.25. A lightweight concrete weight of 0.97 tons, the load that can be supported by the prototype is 1.2 tons. The prototype of the styrofoam material platform with a lightweight concrete cover has a stable condition with a value of m>0, namely the center of object weight (B0) is +0.74 meters and the metacentric value is +0.9 meters.
Did socioeconomic status influence psychological preparedness for potential disaster of resident around lapindo mud disaster
Authors: Palupi L S
Published: March 2021

Lumpur Sidoarjo or known as LUSI is geologicall disaster that has been going on for 14 years since 2006. It is consider as the world’s largest mud volcano eruption. It bring tremendous impact to the livelihood of the resident live around the site. People live around the site mostly relied on the ponds as a living thus LUSI bring a devastated impact to the local communities. The condition has bring negative impact not only to their economic condition but also to their mental health. Study found that there are growing number of people live around the site that experience psychological problem. Psychological preparedness for disaster is one of the factors that could help people in coping with stress after disaster strike. Previous study has found that most of the resident live around the LUSI site has average level of psychological preparedness. Research on psychological preparedness found that one of the factor that associated with psychological preparedness is socioeconomic status. It is said that people with low socioeconomic would also have a low level psychological preparedness. However, the relationship between socioeconomic status and the psychological preparedness in resident around lapindo mud disaster (LUSI) was unclear. Therefore, this study aimed to investigate the relationship between socioeconomic status and the psychological preparedness for potential disaster among resident around lapindo mud disaster. The study was conducted in Sidoarjo. Survey research was applied using a Psychological Preparedness for Potential Disaster scale as a mean to identify the psychological preparedness of the Sidoarjo people.
Analysis of Work Accident Factors in the Shipyard
Authors: Zaman M B , Baheramsyah A , Ashari I
Published: March 2021

In the shipbuilding industry, the majority of ship accidents are caused by human error. other factors are caused by the work environment, company conditions, management policies and others. These data show that human factor has a major impact on accidents. Therefore, a proper prevention is required. The purpose of this research is to determine the relationship between individual characteristics and work accident factors as well as to determine the prevention of work accidents. The method used in this paper is bivariate method. Then, the analysis was conducted using the chi square approach. The result of this research showed that age has a relationship with knowledge of engineering and skill. It has meaning that older workers would most likely understand in engineering better than the younger ones. Work pressure also has a relationship with age. It has meaning that the workers with an age of <35 and >45 have more work pressure than those with an age of 35 - 45. Furthermore, tenure and education do not have a relationship with work accident factors. Thus, some efforts are needed to minimize work accidents, such as providing in-class training to new workers, doing on-job training or field training, providing assistance on every job, exchange of workers from one place to another, sharing sessions on static electricity to young workers, creating a comfortable work atmosphere, provide adequate facilities, provide training on stress management and decision making.
Evacuation Analysis of Ship Passenger Using Agent Based Modelling Simulation
Authors: Zaman M B , Siswantoro N , Zulfikar M
Published: March 2021

Ship accidents that occur in Indonesian have a high frequency. The ship accidents is dominated by fires of Ro-ro or passenger ships which cause material loss, water pollution and loss of human life. In this paper, an analysis of the ship evacuation system will be carried out. The Agent Based Modelling Simulation (ABMS) was using in this study. Initial data required are in the form of ship general arrangement, passenger walking speed, as well as the composition and distribution of passengers. The distribution of ship passengers in Indonesia for the category of women aged less than 30 years is 12%, women aged 30-50 years are 21%, women aged greater than 50 years are 5%, there are no female passengers with disabilities, while for the category of males aged less than 30 years as much as 19%, males with an age range of 30-50 years as much as 31%, males over 50 years old as much as 12%, and no male passengers were found. a man with a disability. The number of ship passengers is conditioned to exceed the passenger capacity, namely 880 passengers should be conditioned to become 1527 passengers. The evacuation simulation of ship passengers using an agent based modelling simulation is run based on the IMO MSC. 1 / Circ. 1533 using 4 cases during the day and night. In the case of a normal night it takes 38.24 minutes to evacuate all passengers, and in the case of a night the evacuation takes 36.45 minutes. In the normal day case it took 29.49 minutes and in the afternoon case the evacuation took 28.12 minutes.
Sedimentation and Longshore Current Simulation with Delft3D Software in Rejoso Shoreline
Authors: Rakhmawati A L
Published: March 2021

Rejoso estuary, located 3 kilometers from the center of Pasuruan, has an unstable river mouth that threatens the existence of residents in the surrounding area. During the rainy season, when high discharge in the river meets high tide from the ocean, flooding occured in residential areas located around the coast. It happens due to sediment deposits formed near the sea and ocean current that worsen the backwater. East Java Provincial Water Resources Agency plans to build a jetty in that area to reduce sediment deposition caused by longshore sediment transport and to protect the estuary from ocean currents. This study aims to look at the impact of jetty construction that is affected by wave and current activity by performing numerical modeling with Delft3D software. From the simulation results, jetty reduce the amount of ocean current with the biggest reduction at monitoring point A is 0.299 m/sec (94.05%) and decrease sedimentation with the biggest at monitoring point A by 91.37% in the east side of the estuary. In conditions without a jetty, the shape of the shoreline and the elevation follows the shape of the initial shoreline, while after one year with jetty the sedimentation occurred to the end of it.
Hydrodynamics Performance Analysis of Vertical Axis Water Turbine (VAWT) Gorlov Type Using Computational Fluid Dynamics (CFD) Approach
Authors: Wardhana W , Keniraras N , Pratama R S , Rahmawati S
Published: March 2021

The Renewable Energy conversion technology has been increasingly developed along with the awareness regarding the negative environmental issues caused by Non-renewable Energy waste. Vertical Axis Water Turbine (VAWT) is an interesting research object because of variety of advantages it offers. The Gorlov type VAWT is famous for its tendency to move regardless the water flow directions and able to rotate twice as fast as the inlet velocity. Things which need to consider important related to the turbine hydrodynamic effects including the quantity of blades, hydrofoil profiles, pitch angle, and turbine’s dimension ratio. In this study, numerous variations were applied to determine the hydrodynamic effects caused especially torque output. Investigations were carried out using Computational Fluid Dynamics (CFD) simulations. The Gorlov type turbine model is simulated in 3D under steady state flow conditions. The software used to run numerical simulations is ANSYS V18.1. The flow model used is laminar according to secondary data analysis. After the numerical simulation results are obtained, validation is performed with an average error rate of less than 10%. Variations chosen in this study is the pitch angle of 40° and 30 °, the dimension ratio in the form of 450 mm in diameter, the type of asymmetrical hydrofoil (S1210), and the quantity of blades (2, 3, 4, 5, and 6). Simulation results in the form of torque values showed that the best turbine performance is provided by NACA 0012 symmetrical hydrofoil with 40° pitch angle.
Monte Carlo Simulation for Reliability Hydraulic Stability of Rubble Mound Breakwater Armour at Sudimoro Power Plant, Pacitan
Authors: Armono H D , Nugroho D K , Mukhtasor and
Published: March 2021

In breakwater design, the conventional deterministic methods are commonly used. This method based on the concept of load, where the design load should not exceed the carrying capacity of the structure. However, the design load itself can be identified using statistics analysis, such as the average value of a 60-years return period of wave. Most of the available design formulas only provide a link between wave characteristics and some structural responses, such as run up, overtopping, or armor layer damage. In this paper, a reliability analysis of the breakwater hydraulic stability of Sudimoro Power Plant, Pacitan is performed with Monte Carlo simulation. The formulas used in hydraulic stability calculations were Hudson and Van der Meer formulas. The analysis shows that the breakwater structure in Pacitan Power Plant already meets the hydraulic stability design with reliability of 98,8% for Hudson and 95,12% for Van der Meer formula. This paper also presents the reliability of breakwater armour units proposed by authors.
Effect of Permeable Structure on Coastal Sediment Transport in Demak Regency, Central Java, Indonesia Model by Using Delft3D Software
Authors: Iqbal M , Widyaningtias  , Wiyono A , Adityawan M B , Sukarno I , Sekaring Bumi I
Published: March 2021

Coastal area in Indonesia are places that has a variety of function both economic, culture and social. As time goes by, coastal areas sometimes damaged because of human activities. Declining coastline that caused by erosion is one kind of problems that might be occurs in this area.

Coastal area in Timbulsloko is the example of coastal area in Indonesia that’s experiencing declining coastline. One of the attempts to resolve this problem is by constructing permeable structure based on Building with Nature concept. One of the methods to find out whether it’s effective or not is by using software modelling to model sedimentation process in this area. By using Delft3D software, there are three model scenario used to model the sedimentation process. the first scenario was made to model sediment transport in the area itself. The second and third scenario were made to model sediment transport in the area with addition of existing permeable structure design. From the results of the models, the first scenario result shows the area is generally eroded. Furthermore, the placement of permeable structure that is simulated in the second and third model was resulting the increasing sedimentation process around the structure. The sedimentaion process around the structures in the third scenario occurs with sedimentation rate around 0.15 – 0.7 m/year. So, the model shows that the permeable structure itself can be used to protect the coastal area from eroding dan helps the recovery of coastal area.
Temperature and Salinity Condition Based on Field Measurement at Pasir Putih Waters Situbondo
Authors: Pahlewi A D , Handayani C
Published: March 2021

Temperature and salinity affect to pollutant dispersion, used as water quality indicator and also limiting factor for organism distribution pattern. Pasir Putih Situbondo state as waters conservation area because of its natural resources diversity. The changes in water temperature and salinity at Pasir Putih water can affect to the living organism in it. Monitoring of water quality become part of the effort to manage the water resources and other related components. The aim of this study is investigate temperature and salinity distribution in Pasir Putih water. Temperature and salinity was measured from 6 stations horizontally. Sampling of temperature and salinity took the surface water and using in-situ methods. The sampling was done in ebb condition. The result of this research is the average temperature and salinity of six sampling locations is 30.7°C and 33.3%o. The temperature and salinity are in normal condition according to standart value in Decree of the State Minister of the Environment Number 51 of 2004.
Design of Reverse Osmosis Desalination Plant at Remote Coastal Area
Authors: Fitri Sutopo Purwono , Baheramsyah Alam , Santoso Agoes , Nugroho Taufik Fajar , Iswantoro Adhi , Ikhwani Hasan , Ditya Danang Jawara
Published: March 2021

During the long dry season hit most parts of East Java in 2019, there were 566 villages in 180 sub-districts that are categorized as dry areas with critical clean water supply, 236 villages in 93 sub-districts as rare dry areas, and 20 villages in 14 sub-districts experienced limited dryness. In big cities in Indonesia, clean water service coverage has only reached 64.3%, while in rural areas still at 69.4%. This proves that most of the regions in Indonesia still experiencing a clean water crisis. Therefore, alternative clean water processing technology is needed to help supply clean water in these areas. Desalination as one of the technologies is essential for coastal areas that are remote from freshwater resources. In this paper, authors propose a design of photovoltaic reverse osmosis (PVRO) desalination plant at remote coastal area to supply clean water. A 100 m3/day design of PVRO, which is compact and energy efficient including the ultrafiltration method is introduced.
Efficient Coordinated Dust Removal Technology and Economic Analysis of Desulfurization System Under Ultra-Low Emission Situation
Authors: You L Z , Zhu Y
Published: March 2021

Base on the ultra-low emission reconstruction project of the 2×600MW unit desulfurization system in the Northwest China. The desulfurization system synergistic dedusting technology route achieves ultra-low emission of soot under the premise of maximizing the use of existing equipment. Through the comparison of the three-stage roof demister, Tube type dedusting and demisting device and condensing type dedusting and demisting device technology, the three-stage roof demister is stable, mature and reliable, and widely used. Under the same transformation conditions, the cost of the three-level roof demister is lower than the other two dust removal and demisting devices.
Lithium-Ion Battery Thermal Runaway Electro-Thermal Triggering Method and Toxicity Analysis
Authors: Xie H J , Sun J , Li J G , Zhou T , Wei S P , Yi Z H
Published: March 2021

In high temperature condition, lithium-ion batteries have a greater risk of thermal runaway. Lithium-ion batteries may be exposed to smoke, combustion, or even explosion, which poses a greater threat to humans and the environment. In this paper, the electro-thermal triggering method is used to induce thermal runaway of the lithium-ion batteries. The most representative ternary polymer lithium-ion battery (NMC), lithium cobalt oxide battery (LCO), lithium iron phosphate battery (LFP) in the market were selected as experimental samples, all using 18650 batteries, and then the state of charge of battery samples were adjusted to 0%, 30%, 50%, 100%. The thermal runaway reaction phenomenon of lithium-ion batteries and the surface temperature of the batteries were recorded. The positive electrode samples of the batteries were characterized by X-ray diffraction and electron microscopy, and the thermal runaway reaction products were analyzed. The results show that with the increase of the state of charge, the thermal runaway reactions of the batteries are more severe. Thermal runaway reaction products contain a large amount of toxic substances, and prevention and protection are necessary.
A Short-Term Electricity Forecasting Scheme Based on Combined GRU Model with STL Decomposition
Authors: Tian Y J , Zhou S J , Wen M , Li J G
Published: March 2021

With development of smart grid, the stable operation of grid has put forward higher requirements for system dispatch. In particular, short-term load forecasting of power systems is a key factor of power grid management systems, which is related to the safety, economy, and stable operation of the smart grid. However, short-term electricity forecasting is affected by many external factors. It has complex characteristics, especially non-linear relationships, so it cannot be accurately predicted. Recently, Recurrent Neural Network based models have good performance in electricity forecasting because of their excellent ability to capture non-linear relationships. However, they cannot fully capture historical information, especially local historical information, which has an impact on prediction accuracy. In order to address these problems, we propose a scheme by combining STL decomposition and GRU model. Specifically, we first decompose the original time series into three different components by STL. The decomposition results are separately imported into the main prediction module, which uses two GRU networks with different structures to obtain the local and global dependencies of the data. We also add an autoregressive method to make the model more robust. The proposed scheme is validated based on real-world data, and the simulation results show that our proposed method can perfectly capture local and global information and achieve higher prediction accuracy than traditional models.
A Decision Support System for the Planning of Hybrid Renewable Energy Technologies
Authors: Kazak J K , Mrówczyńska M , Skiba M , Bazan-Krzywoszańska A , Świąder M , Tokarczyk-Dorociak K , Szewrański S
Published: March 2021

Implementation of renewable energy resources (RES) with the use of knowledge-based approach requires systems which enable to combine data from different databases in order to multidimensional character of analysed factors. Therefore, this study provides the decision support system for the planning of hybrid renewable energy technologies designed for regional authorities. The system in this research integrates two RES: solar and wind. Moreover, it combines energy potential data with administrative division and data on land cover. Presented functionality shows the ability of single-element filtering as well as multi-element filtering which gives the opportunity visual data discovery. The novel decision support system designed in this research can constitute an effective instrument, which can help regional decision-makers to locate single-source as well as hybrid RES installations to meet the requirements of renewable energy production. The systems were designed for the case of Lubuskie Voivodeship (Poland). However, besides the fact of customized system for one region, the use of universal databases allows to prepare similar tool for any other region in European Union.
Study on Difference Between Two-Terminal LCC-HVDC and Three-Terminal LCC-HVDC Control and Protection System
Authors: Feng L
Published: March 2021

The paper studies the difference between two-terminal Line Commutate Converter Based High Voltage Direct Current (LCC-HVDC) and three-terminal LCC-HVDC control and protection system relying on the Yun-gui Interconnection Project of China Southern Grid (CSG). Contraposing the difference of topology between two-terminal LCC-HVDC and three-terminal LCC-HVDC, the paper introduces several special topology structures of three-terminal LCC-HVDC. Then the paper conducts comparative analysis on control strategy, protection strategy and communication strategy between the two-terminal LCC-HVDC and the three-terminal LCC-HVDC. Finally, the paper illustrates the unique key problems of three-terminal LCC-HVDC and solving ideas, which has guiding significance on three-terminal LCC-HVDC engineering application.
Research about the Sensorless Vector Control of Permanent Magnet Synchronous Motor Based on Two-stage Filter Sliding Mode Observer
Authors: Yang C , Jian W , Chen Y F , Huang X C , Li Y R , Peng G S , Gao Y
Published: March 2021

In order to overcome the disadvantages of installing mechanical sensors and the problems of chattering and low observation accuracy in traditional sliding mode observer sensorless control, a two-stage filter Sliding Mode Observer (SMO) is proposed in this paper. By collecting the current and voltage of the Permanent Magnet Synchronous Motor (PMSM), the SMO algorithm is realized by using the state equation of the motor in the synchronous stationary coordinate system; the position of the rotor is estimated by the arc tangent function, the observation accuracy of the rotor position is improved by increasing phase compensation; the variable cut-off frequency filter is introduced to make the Low Pass Filter (LPF) cut-off frequency can be self-adjusted with the change of rotational speed, which improves the estimation accuracy of rotor position at different rotational speeds. Kalman filter is introduced to form a two-stage filter with variable cut-off frequency LPF, which greatly weakens the chattering of the motor and reduces the observation error. Finally, the simulation is carried out under MATLAB/Simulink. The simulation results show that the PMSM vector control system with two-stage filter sliding mode observer has high estimation accuracy, good dynamic and steady-state performance, strong anti-jamming ability and robustness.
Evaluation of Minimum Boundary Output Stability of Thermal Power Units
Authors: Han Y , Cai B , Wang Y K , Yü Y L , Gao Z P , Fu X C
Published: March 2021

In order to improve the load regulation capability of the power grid, verification of the minimum boundary output characteristics of deep peak regulation of coal-fired units was carried out. Considering the safety, stability, environmental protection, and energy saving indicators, the minimum output stability evaluation method was discussed in a 300MW coal-fired unit, and the ultra-low combustion stability target of 25% of rated load was completed. This has important guiding significance for approving the output characteristics of units, carrying out precise load regulation, and expanding new energy consumption.
Optimal Scheduling of MGT-IES Considering Heat Load Uncertainty and Heating Characteristics
Authors: Kong X F , Shen J , Li Y X , Zhang J L
Published: March 2021

Considering the thermal and electricity needs of users in the integrated energy system, in recent years, combined heat and power systems with micro gas turbines as the core have been widely used in integrated energy systems. How to coordinate and schedule heating and power supply in an integrated energy system is very important. In this paper, we take a micro gas turbine-integrated energy system (MGT-IES) as the research object, aiming at the uncertainty of heat load, we adopt a multi-scenario random planning method, while combining user heating comfort the degree of ambiguity and the thermal inertia of the heating system are considered. The indoor thermal comfort index is used to convert the heat load demand from the traditional curve to the interval, so that the heat load is elastic at each point in time, and finally it is established to be more in line with the actual optimal scheduling model. The case analysis shows that after comprehensively considering the uncertainty of the heat load side and the thermal characteristics of the heating system, MGT-IES can effectively reduce the operation cost of the optimized dispatching while meeting the user’s heat load demand.
Optimization of the Configuration of the CCHP System
Authors: Mohsin T , Shen J , Zhang J L
Published: March 2021

In this article, we have optimized the total operational cost of combined cooling heating and power system (CCHP). This cost is further divided into three major parts, which are the capital cost of the equipment, fuel cost, and the grid electricity cost. The heat storage tank has also been used to store the excessive heat that can be utilized when needed. A genetic algorithm has been used for the optimization of the whole system. The decision variables chosen were 74. The optimization resulted in significant reduction in the total cost. The final results show that the cooling demand was significantly supplied by the Grid through the electric chillers because of higher coefficient of performance, while the power demand was met through the power generation unit. Results shows that the natural gas cost consumption is much greater then the grid and equipment cost.
Influence of the Access of Distributed Generation on the Distribution Network System of Inner Mongolia Power Grid and Countermeasure Analysis
Authors: Tao K , Yuan H , Fan H L , Sarengaowa  , Sun Z B , Yi X L , Li Y Q
Published: March 2021

Solar energy resource is highly rich in Inner Mongolia regions, and the customers utilized electric are scattered in the vast grassland. Thus, the distributed generation with its unique performance and high quality, has been developed rapidly in recent years. However, the large-scale distributed power supply has brought many unpredictable impacts when they are accessed to the distribution network, even seriously affecting the safe and stable operation of the distribution network. In this work, the technical barriers caused by distributed power generation to the grid-connected have been explored. In addition, the constraints and key influencing factors of distributed generation on distribution network have also been analysed and a safe and stable operation strategy to access distributed photovoltaic power supply into the network has proposed. The results here could provide a theoretical guidance for the rapid formulation and optimization of the distributed power accessing into grid network in Inner Mongolia power grid.
Fabrication of A New Asphalt Binder for Road Applications
Authors: Liu Z
Published: March 2021

A new asphalt binder for road applications was prepared by mixing coal tar pitch and petroleum asphalt, and then modifying with compound modifier which was made by ourselves. Coal tar pitch and petroleum asphalt was 1:1 for weight. The modifier was made with epoxy resin, chopped carbon fiber which was modified by 3-Aminopropyltriethoxysilane (KH-550) and other auxiliaries. According to “Standard Test Methods of Bitument and Bituminous Mixture for Highway Engineering” JTG E20-2011, the properties of the modified asphalt (MA) were studied, and the best modification technology was mechanical shear of 3000r/min shear rate for 30mins at 110 °C, the amount of modifier was 5%. The properties of MA mixture were also researched, the performance of AC-20 mixture can meet the JTG F40-2004 “Specification for construction of highway asphalt pavement” in the relevant requirements. The oil-stone ratio was 4.7%. The requirement of dynamic stability was ≥ 800n/mm, the wheel tracking test showed the MA mixture exhibited a value of 1323n/mm, which meet the requirement. The MA mixture low-temperature property was studied by the beam bending test, the results indicated a higher value than the AH-70 mixture standard. The Freeze-thaw split test demonstrated the MA mixture water stability meet the requirement for asphalt. In all, a new asphalt binder for road applications was obtained by mixing coal tar pitch and petroleum asphalt, its properties meet the standard of AH-70 and its mixture. The modifier was added for 5% and the effect was best.