bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of a preclinical PET insert in a 7 tesla MRI scanner: beyond NEMA testing
Authors: Gsell Willy , Molinos Cesar , Correcher Carlos , Belderbos Sarah , Wouters Jens , Junge Sven , Heidenreich Michael , Velde Greetje Vande , Rezaei Ahmadreza , Nuyts Johan , Cawthorne Christopher , Cleeren Frederik , Nannan Lise , Deroose Christophe M , Himmelreich Uwe , Gonzalez Antonio J 
Published: June 2020

Abstract
This study evaluates the performance of the Bruker positron emission tomograph (PET) insert combined with a BioSpec 70/30 USR magnetic resonance imaging (MRI) scanner using the manufacturer acceptance protocol and the NEMA NU 4–2008 for small animal PET. The PET insert is made of 3 rings of 8 monolithic LYSO crystals (50 × 50 × 10 mm3) coupled to silicon photomultipliers (SiPM) arrays, conferring an axial and transaxial FOV of 15 cm and 8 cm. The MRI performance was evaluated with and without the insert for the following radiofrequency noise, magnetic field homogeneity and image quality. For the PET performance, we extended the NEMA protocol featuring system sensitivity, count rates, spatial resolution and image quality to homogeneity and accuracy for quantification using several MRI sequences (RARE, FLASH, EPI and UTE). The PET insert does not show any adverse effect on the MRI performances. The MR field homogeneity is well preserved (Diameter Spherical Volume, for 20 mm of 1.98 ± 4.78 without and −0.96 ± 5.16 Hz with the PET insert). The PET insert has no major effect on the radiofrequency field. The signal-to-noise ratio measurements also do not show major differences. Image ghosting is well within the manufacturer specifications (<2.5%) and no RF noise is visible. Maximum sensitivity of the PET insert is 11.0% at the center of the FOV even with simultaneous acquisition of EPI and RARE. PET MLEM resolution is 0.87 mm (FWHM) at 5 mm off-center of the FOV and 0.97 mm at 25 mm radial offset. The peaks for true/noise equivalent count rates are 410/240 and 628/486 kcps for the rat and mouse phantoms, and are reached at 30.34/22.85 and 27.94/22.58 MBq. PET image quality is minimally altered by the different MRI sequences. The Bruker PET insert shows no adverse effect on the MRI performance and demonstrated a high sensitivity, sub-millimeter resolution and good image quality even during simultaneous MRI acquisition.
Lightning network: a second path towards centralisation of the Bitcoin economy*
Authors: Lin Jian-Hong , Primicerio Kevin , Squartini Tiziano , Decker Christian , Tessone Claudio J 
Published: June 2020

Abstract
The Bitcoin lightning network (BLN), a so-called ‘second layer’ payment protocol, was launched in 2018 to scale up the number of transactions between Bitcoin owners. In this paper, we analyse the structure of the BLN over a period of 18 months, ranging from 12th January 2018 to 17th July 2019, at the end of which the network has reached 8.216 users, 122.517 active channels and 2.732,5 transacted Bitcoins. Here, we consider three representations of the BLN: the daily snapshot one, the weekly snapshot one and the daily-block snapshot one. By studying the topological properties of the binary and weighted versions of the three representations above, we find that the total volume of transacted Bitcoins approximately grows as the square of the network size; however, despite the huge activity characterising the BLN, the Bitcoins distribution is very unequal: the average Gini coefficient of the node strengths (computed across the entire history of the Bitcoin lightning network) is, in fact, ≃0.88 causing the 10% (50%) of the nodes to hold the 80% (99%) of the Bitcoins at stake in the BLN (on average, across the entire period). This concentration brings up the question of which minimalist network model allows us to explain the network topological structure. Like for other economic systems, we hypothesise that local properties of nodes, like the degree, ultimately determine part of its characteristics. Therefore, we have tested the goodness of the undirected binary configuration model (UBCM) in reproducing the structural features of the BLN: the UBCM recovers the disassortative and the hierarchical character of the BLN but underestimates the centrality of nodes; this suggests that the BLN is becoming an increasingly centralised network, more and more compatible with a core-periphery structure. Further inspection of the resilience of the BLN shows that removing hubs leads to the collapse of the network into many components, an evidence suggesting that this network may be a target for the so-called split attacks.
Discovery of an unconventional charge modulation on the surface of charge-density-wave material TaTe4
Authors: Sun Haigen , Shao Zhibin , Luo Tianchuang , Gu Qiangqiang , Zhang Zongyuan , Li Shaojian , Liu Lijun , Gedeon Habakubaho , Zhang Xin , Bian Qi , Feng Ji , Wang Jian , Pan Minghu 
Published: June 2020

Abstract
Electronic systems with quasi-one-dimensional (Q1D) Fermi surface tend to form either a charge-density-wave (CDW) or a spin-density-wave ground state at low temperatures due to one-dimensional instabilities. Among various CDW states, surface CDWs are different from that within the bulk due to the reduced dimensionality. Here we report the systematic investigation of charge density modulation on the surface of in situ cleaved TaTe4 crystal by means of low temperature scanning tunneling microscopy/spectroscopy, corroborated with density functional theory calculation. Well-defined Q1D modulation (4a, 6c) accompanied with a periodic lattice distortion is clearly observed on the (010) cleaved surface, distinct from that of its bulk CDW (2a × 2a × 3c). Tunneling spectroscopic measurements reveal a partially-opened energy gap about 23 meV around Fermi level. Such gap shows similar spatial variation with the periodicity of surface modulation and diminishes subsequently as temperature rises, which indicates a novel surface-related CDW gap states. The surface modulation vectors fit well with the Fermi surface nesting vectors, derived from the calculated Fermi surfaces. Surprisingly, such surface modulation can be suppressed greatly by applying vertical magnetic field and a critical field about 9.05 T can be estimated from field-dependent data. Our results demonstrate that this unique CDW modulation is strongly related to Fermi surface nesting mediated electron–electron coupling due to the reduced dimensionality of the surface, and can be readily tuned by relatively small magnetic field.
Assessment of Malaysian E-Passport PKI based on ISO 27000 Series International Standards
Authors: Suhaimi Ahmad Iqbal Hakim bin , Noordin Nurulhuda , Ya’kub Mohd Faizul bin 
Published: June 2020

Abstract
Malaysia was the 1st country in the world to issue biometric passports (e-Passport) in 1998. Recent years, a number of vulnerabilities in e-Passport have been identified in the first and second generation of e-Passports. These vulnerabilities can lead to crucial security issues. Due to lack of case studies conducted to review the Malaysian e-Passport, the objectives of this study are to identify the security risk in Malaysian e-Passport PKI and to recommend the feasible solution for future enhancement. A qualitative method was used in this study where a set of interview questions prepared and interviews been conducted to four participants. The data been analyzed using Thematic Analysis and presented based on risk assessment methodology in ISO 27000 series International Standards. The risk assessment consists of two approaches; risk analysis and risk evaluation. The risk analysis identified resource identification and valuation, risk identification and risk measurement of Malaysian e-Passport PKI. While in risk evaluation, it focuses on risk mitigation and prioritizing protection activities for future enhancement. The results reveal that the Cloning, Man in the Middle, Spoofing and server related issues are the risk of Malaysian e-Passport. For recommendation, the result is to implement Password Authenticated Connection Establishment (PACE) and follow ICAO standards. The significance of this research will help policy-makers to make better decision on the future direction of Malaysian e-Passport in order to ensure Malaysian citizens having secured e-Passport.
Identification of Information Security Threats Using Data Mining Approach in Campus Network
Authors: Awang Norkhushaini , Samy Ganthan Narayana , Hassan Noor Hafizah , Maarop Nurazean , Magalingam Pritheega , Kamaruddin Norshaliza 
Published: June 2020

Abstract
Comprehensive risk assessment implementation in an organization is crucial in order to safeguard valuable organization assets and to minimize information security threats. Thus, inadequate information security risk assessment may result in compromised confidentiality, integrity, and availability of the information system due to unauthorized access particularly in the education domain. Therefore, the objective of this paper is to identify several information security threat risks related to the University Information System. Hence, data from intrusion prevention system (IPS) has been collected from the selected university campus network. Moreover, under Python language, Anaconda is used as a machine learning environment to do the data analysis of the collected data. Basically, the analysis of the university campus network data identified various types of information security threats such as database-related attacks. The contribution of this research is to guide the network administrator to develop an appropriate incident response plan based on the identified threats from the risk assessment activity.
Implementing Location-Based Cryptography on Mobile Application Design to Secure Data in Cloud Storage
Authors: Shamsuddin Nur Syafiqah Mohd , Pitchay Sakinah Ali 
Published: June 2020

Abstract
This paper aims to identify security issues and existing solutions for cloud storage protection and to propose a mobile application design for securing data in cloud storage using the location-based cryptographic technique. In the proposed mobile application design, the user is required to perform the encryption before sending the data into the cloud storage. This paper provides a novel technique using location-based cryptography, secret keyword and hash function in order to further enhance the security of data in cloud storage that is currently only using either asymmetric or symmetric encryption algorithm. Asymmetric encryption’s has high security but due to the complexity in its computing, the performance rate is low while symmetric encryption’s performance is much faster as its implementation is easy. However, the attacker can still hack the data in cloud storage when either one of this encryption methods being used alone without any additional security layer. In this paper, location-based cryptography technique used consists of Advanced Encryption Standard (AES) algorithm and location information which are longitude and latitude coordinates. Those coordinates will be employed in the encryption and decryption process as additional security mechanism on top of existing cryptography method by generating supplementary encryption key called geo-lock key. Dynamic Toleration Distance (DTD) protocol will also be implemented with those coordinates to improve its practicality before it will be converted into the geo-lock key. AES algorithm will handle encryption and decryption process using the geo-lock key while secret keyword which defined by the user before starting the process will be used to authenticate the upload and downloading process. Both geo-lock key and secret keyword will be hashed using Secure Hash Algorithm 2 (SHA 2) and stored together with encrypted file in the cloud storage. The purpose of using location information is to ensure the encrypted file can be decrypted at intended location only while hash function is employed to protect the keys when they are stored in cloud storage. As a result, any unauthorized access to the file in cloud storage will not be allowed since each stored file was encrypted by the high performance of AES algorithm together with the decryption’s location restriction and the non-reversable hashed keys. The proposed mobile application design will serve an improvement in protecting stored data at cloud storage by using AES algorithm with location information as data encryption method and SHA 2 function for hashing the keys.
The Progressive Multilevel Embedding Method for Audio Steganography
Authors: Alsabhany Ahmed A. , Ridzuan Farida , Azni A. H. 
Published: June 2020

Abstract
Audio steganography refers to hiding a secret message inside a cover audio file. The existing methods follow almost a sequential embedding which leads to poor utilization of the cover. The proposed method aims to achieve the maximum feasible capacity of the audio file without lowering the quality. The proposed method is based on seven levels of thresholds and six LSB layers, while the embedding is carried out progressively. The method allocates the message bits over the cover signal horizontally to ensure fair payload distribution over the signal. Hence, the selected samples might be visited multiple times till the message is totally embedded. The experimental results show that the method is able to reach a hiding capacity of 40% of the file size or 266.6 kbps while maintaining an SNR and PSNR values of 40 and 58 dB respectively. It is concluded that the proposed progressive method is highly adaptive to the message size and capable of providing high-quality stego even when big payloads are used. The comparative study shows that the progressive method provides the best message distribution based on the nature of the cover.
Fractional charged leptons in a 331 Model
Authors: Romero Abad D , Ramirez Barreto E 
Published: June 2020

Abstract
The extensions of the Standard Model based on

S
U

(
3
)

C

⊗
S
U

(
3
)

L

⊗
U

(
1
)

X

gauge group are known as 331 Models. Different properties, as the fermion assignment and the electric charges of the exotic spectrum, that defines a particular version of the model, are fixed by a parameter β. In this work, we explore a 331 version, set by the condition

β
=

1
/

(
3

3

)

, where new particles arise with peculiar signatures as heavy fractionally charged leptons and electrical neutral quarks, among others. We examine different sectors of the model with emphasis in the Yukawa lagrangian of the new leptons, in order to study their branching fraction for scalar particles.
OAUNI astronomical photometry: Stellar variability of FO Aqr on 2016 low state
Authors: Pereyra A 
Published: June 2020

Abstract
This work reports a photometric monitoring of the intermediate polar cataclysmic variable star FO Aqr. This is part of the ongoing OAUNI stellar variability program. Around 1200 individual measurements (or ∼ 9 hrs of observations) were gathered distributed in five nights. The observation epoch was coincident with the 2016 low state brightness of FO Aqr. Good quality light curves detect unambiguously the expected stellar variability of FO Aqr. The analysis using periodograms let to determine the main two known periods, P1 = 20.380 ± .003 min and P2 = 11.076 ± .001 min. Our full five-nights analysis shows that P1, the spin white dwarf period, is more prominent than P2, the one-half of the beat period between the spin and orbital periods. Nevertheless, individual light curves show than, at least in one case, a reverse pattern is found. It suggests a dependence of the beat period with the orbital phase of the system with important variations at the same phase interval.
Axially Symmetric Configuration in the Skyrme Gauge Model
Authors: Rybakov Y. P. , Benavente Ramirez E. , García Roca Sayri T. 
Published: June 2020

Abstract
The structure of axially symmetric fields in the skyrme model with a gauge field is studied. The Hamiltonian and topological charge are constructed in the corresponding invariant class. A discrete internal group of the model is indicated, which allows to simplify the energy functional significantly.
Chirality and neutrinos, a student first approach
Authors: da Motta Hélio 
Published: June 2020

Abstract
Does Nature care about left-handed and right-handed configurations? Are left and right just two versions of the same thing? Although at first we may think that a particular orientation is irrelevant the fact is that Nature may distinguish between left-handed and right-handed systems. This results in different behaviors and properties. In this short presentation we will approach this phenomenon and how it affects the neutrinos.
Automation of a seed on tray seeder machine
Authors: Arteaga Oscar , Amores Katherine , Terán Héctor , Cangui RicharS. , Ramírez André , Hurtado C Samanta , Inlago Dayana , Chuquimarca Bryan R 
Published: June 2020

Abstract
The machine aims to fully automate the process to sow seeds. Generally, these types of activities are semi-automatic, however, the proposed solution aims to improve the efficiency of the process and the reduction of human intervention. It mainly has a mechanical part whose technique is based on a four-bar system, as for the electronic and control part it is commanded by an Arduino card. The mechanical design was carried out using CAD software, and based on the results obtained by various flexural and deformation analysis software, it was possible to select the materials and the motor to be used. The process works from operational requirements such as: transmitting the linear movement of the components, placing and aligning the transport mechanism, transmitting enough power to drill and place the seeds and finally controlling the air flow. As a result, this automated method represents 25% more efficiency and a 50% reduction in personnel compared to the manual method. In the same way, a filling of 87% of cavities for seeds was obtained, this being its highest efficiency with a pressure in the range of 0.2 to 0.3 MPa in the pressure ejector.
Energy-distance & degree: multi-objective based optimized clustering and route discovery in wireless sensor network
Authors: Mahendran N , Mekala T 
Published: June 2020

Abstract
Network lifetime (NL) and energy preserving of sensor node is the most vital problem in the deployment of wireless sensor networks (WSNs
). An approach of cluster based path establishment shows the way in which cluster heads (CHs
) collect the information with each other and transfers into the sink (nS
) via multi-hop routing. In this paper, we present path establishment and CHs
selection through Energy-Distance and Degree (EDD) based clustering (EDDCH) and route discovery (EDDRD). The networks divided into multiple groups and each CHs
support to each other for data forwarding also the smaller sized clusters closest to the nS
and huge size clusters remote from the S increases the lifetime of the network. The simulation results compared with the existing route optimization named as Particle Swarm Optimization (PSO) in terms of residual energy (RE
) and network lifetime (NL
).
Analysis of gate engineered asymmetric junctionless double gate MOSFET for varying operating conditions
Authors: Mendiratta Namrata , Lata Tripathi Suman , Prakash Kolla Bhanu 
Published: June 2020

Abstract
In this paperan asymmetrical junctionless double-gate MOSFET(AJDG-MOSFET) has been analyzed using different gate oxide material like SiO2 and HfO2 and different gate contact material like aluminium, copper and polysilicon. To check the sensitivity of AJDG-MOSFET, a temperature analysis has been performed at a different temperature ranging 250-400K. The performance of AJDG-MOSFET is analyzed with transfer and output characteristics using 2D/3D simulation on Cogenda TCAD. The device performs better using HfO2 as gate oxide and polysilicon as gate contact. The ideal subthreshold performance (DIBL=65mV/V, SS=68 mV/decade) is observed with a high value of Ion/Ioff(∼1012) for 300K temperature. The analysis for temperature shows a very small variation in OFF current and found suitable for low power applications.
Recycling of lithium ion batteries using fungi based organic acids
Authors: Navaneethakrishnan V , Pavithra K , Vanitha V 
Published: June 2020

Abstract
There is a huge demand for the rechargeable Lithium ion batteries around the world as they act as the energy source for the electronic gadgets like smart phones, lap tops etc. There is also a revolution in the automotive sector in the form of electric vehicles(EVs)because of the depletion of fuels and environmental issues. The evolution of battery technology in the automotive sector has resulted in the usage of Lithium ion battery in electric vehicles because of the advantages such as eco-friendly, light weight, compactness and fast charging. Having a huge demand on one side, the trace of Lithium metals in the earth’s surface is getting reduced. For sustainable growth of electric vehicles, an effective and economical recycling technique for Lithium ion batteries is necessary. This paper focuses on the recycling of Lithium ion batteries using organic acids namely malic acid and citric acid obtained from fungi, namely ustilagotrichophora and Aspergillusniger. The batteries are leached with these organic acids and the precipitate of corresponding metals are obtained, which could be used for further manufacturing of batteries. A CAD model for the lithium ion battery recycling plant with safety measures to be followed is developed using AUTOCAD and its technical feasibility is discussed in this paper.
Energy efficiency sink based data collection protocol in WSN
Authors: Lalitha T , Nandhini K , Fairose Shebaa 
Published: June 2020

Abstract
A sensor node is that the significant part of a wireless sensor network. Sensor nodes have various roles in a network includes identifying data storage, data processing and routing method. Cluster is an organizational element for wireless sensor networks. The powerful environment of this network is very essential for them to be broken down into clusters to make easier responsibilities such as communication. Cluster heads are the group head of a cluster have greater data rate match the alternative cluster member. They frequently needed to associate activities within the cluster. These methods comprise but are not controlled to data aggregation and forming account of a cluster. Base station is at the upper level of organized wireless sensor network. It generates communication link among the sensor network and the end user. The data in a sensor network can be used for an enormous variety of applications. A detailed application is form use of network data over the internet retaining a personal digital assistant or desktop computer. This paper contributions mobility based reactive protocol named “Mobility of Sink based Data Collection Protocol (MSDCP)”. This protocol sensor with great energy and maximum quantity information are picked as cluster heads that gather data from the common nodes between the clusters. This data is placed unless mobile sink comes within the transmission area of cluster heads and request for the gathered data. One time the request is received from cluster head and it forward data to the mobile sink.
Metal contact RF MEMS switch design for high performance in Ka band
Authors: Narang Niharika , Singh Pushparaj 
Published: June 2020

Abstract
RF/microwave systems require switches to achieve tunability and reconfigurability. MEMS switches have always been a priority due to excellent RF performance (low insertion loss and high isolation). In this work, we present an RF Micro-Electro-Mechanical-System (RF MEMS) series switch that provides insertion loss less than 0.6 dB (on switch) and isolation better than 15 dB (off switch) at 40GHz. The designed switch consists of serpentine arms on the fixed end and two free-moving arms on another end. These free arms have individual contact points to overcome asperity problem during on state. To avoid self-actuation, bumps (0.6um) are used at the bottom side. This electrostatically actuated switch requires a pull-in voltage of 3.1V for 2.4 μm displacement in 67.14 μs time. The proposed switch is analysed in COMSOL software, and its RF characteristics are simulated in HFSS.