Unlocking Process Research Articles

Study on pyroshock response of micro-satellite pyrotechnic cutter

When the micro-satellite panel is deployed in orbit, it needs to be unlocked by the pyrotechnic device. The high-amplitude pyroshock environment generated in the unlocking process is fatal to the sensitive components on the satellite. Therefore, accurate and quantitative analysis of the structural response caused by the explosion can better understood the transmission characteristics of pyroshock, so that effective isolation methods can be carried out. In this paper, the finite element model of the pyrotechnic cutter is established in LS-Dyna, and the explosive unlocking process of the pyrotechnic cutter is simulated by the Particle Blast Method (PBM). The whole motion process of the cutter from unlocking to cutting off the pretightening rod is obtained, the distribution of stress and the propagation law of pyroshock wave are extracted. The results show that before unlocking, the explosion shock is the main part of the pyroshock, while after unlocking, it is mainly caused by the prestress release of the pretightening rod and the impact of the cutter hitting the cutting board. Explosive shock is the main factor affecting the near-field pyroshock, while the far-field pyroshock is mainly affected by the impact. To verify the accuracy of the simulation, a unlock test of pyrotechnic cutter are performed, the acceleration response values of the main reference points are obtained, and the results show that the two results are in good agreement in time domain and frequency domain. Based on the study of the separation characteristics, some suggestions on the optimization of damping buffer are proposed here.

A cysteine/lipid droplets sequentially activated dual-locked fluorescent probe for accurate bioimaging of tumor tissues

The previous activatable probe toward one analyte can still produce imprecise signal as a result of the challenge cased by accurate identification in complex biological environment. As smarter molecules, dual-locked probes are able to respond to two different analyte with one or more output signals, which display significantly reduced background interference and increased spatial resolution. In this study, a smart cysteine/lipid droplets sequence-activated dual-locked fluorescent probe CN–NO2 has been designed and synthesized for the detection of tumor tissues. The recognition group of CN–NO2 removed after reacting with cysteine (Cys) and undergoing intramolecular rearrangement to generate complete fluorophores. This structure had a strong solvent effect; it could recognize lipid droplets (LDs) in cells, thus exhibiting fluorescence without secondary molecular adjustment. The fluorescence of CN–NO2 was enhanced 1752-fold after double unlocking. Importantly, the unlocking process only takes 10 min. Furthermore, the fluorescence of CN–NO2 was amplified remarkable and anchored at LDs after reacting with Cys in A549 cells. Therefore, CN–NO2 clearly indicated the site of mouse xenograft tumor in vivo. Such sequence-activated dual-locked fluorescent probes are envisioned to execute more analysis and diagnostic tasks giving these unique characteristics.

The Unlocking Process Leading to the 2016 Central Italy Seismic Sequence

AbstractApproximately 23,000 well‐located earthquakes from 2009 to 2016 are used as templates to recover seismic activity preceding the 2016 Central Italy seismic sequence. The resulting spatiotemporal pattern is analyzed by additional ∼91,000 newly detected events. In the 8 years before the sequence onset, seismicity (ML ≤ 3.7) develops at the hangingwall of the 2016 normal faults and along a sub‐horizontal shear zone, bounding the active extensional system at depth. This activity, mainly organized in foreshock‐mainshock and swarm‐like clusters, migrates toward the nucleation area of the first Mw 6.0 mainshock of the sequence (24th of August in Amatrice). We propose an unlocking process based on variable temporal clustering of the seismicity, including repeaters, identifying fault portions with different degrees of coupling. Such a progressive localization of the seismic activity at the fault edges induces a weakening of the locked patch of the Amatrice mainshock.

PresSafe: Barometer-Based On-Screen Pressure-Assisted Implicit Authentication for Smartphones

Graphic-pattern-based implicit authentication has been successfully exploited to elevate the security of smartphones. On-screen pressure is one of the key features in such an approach since it can reveal users’ touch pattern. However, state-of-the-art approaches rely on a system API to obtain on-screen pressure, which is not adequately accurate and cannot meet the demands of robust implicit authentication. To bridge this gap, we propose PresSafe, a novel implicit authentication system that utilizes the smartphone’s built-in barometer sensor to measure pressure during the unlocking process, and to utilize the pressure data in authentication. A key technical challenge in utilizing barometer sensing, however, is to understand the user activity through measured pressure. To overcome this challenge, PresSafe leverages barometer data along with data from other conventional but heterogeneous ambient sensors to produce accurate and robust user activity descriptions. PresSafe utilizes a transfer-learning-based hybrid workflow to integrate user activity representation learning with a lightweight classical authentication algorithm to obtain a unified model. This approach offloads the computational cost from the terminal and addresses privacy concerns. To ensure applicability of our approach despite data heterogeneity and insufficient training data, we utilize a channel-adaptive data processing mechanism. Extensive experiments utilizing more than 70000 records from 23 volunteers in six different locations show that PresSafe achieves an FAR of 0.45%, an FRR of 0.49%, and an EER of 0.47%, which clearly demonstrate its superiority over several existing solutions.

Assessment of the effect of COVID-19 Lockdown on Water Quality of Baldi River Sahastradhara Sulphur Spring, Dehradun, Uttarakhand, India

Due to imposed restrictions during COVID-19 lockdown on air- rail - road traffic and industrial activities,early signs of improvement in water quality of several Indian rivers were noticed in terms of higher dissolvedoxygen and lower biochemical oxygen demand and total Coliforms, on account of least discharge of industrialeffluents and restricted human outdoor movement. In the backdrop of above, this study was aimed toassess the water quality index (WQI) of Baldi River -Sahastradhara Sulphur Spring, Dehradun, India, byfollowing the U.S. National Sanitation Foundation, NSF-WQI model, during lockdown (April to June 2020)and after unlocking process (July – September, 2020). The spatial and seasonal variations in ten waterquality parameters of Baldi River -Sahastradhara Sulphur Spring were investigated by monitoring thewater quality at three locations; Baldi river upstream, Sahastradhara proper and Baldi river downstream. Duringthe entire study period, improved water quality was observed, in terms of high DO ranging from 9.17±0.035to 8.38±0.028 mg/L and comparatively low BOD ranging from 1.68±0.032 to 2.31± 0.031 and low totalcoliform counts ranging from 06±1.09 to 31±2.75 MPN/100 mL. The NSF-WQI water quality status ofBaldi River -Sahastradhara Sulphur Spring was found to be Good all the time and the computed WQI atBaldi river upstream, Sahastradhara proper and downstream were 85.53, 83.48 and 82.30 during lockdownperiod (summer). However, during unlocking process (monsoon), due to continued weekend restrictions,on account of minimum tourists activities the water quality was still computed Good that NSF-WQI werefound to be 83.20, 80.58 and 79.27, at the studied locations respectively.

SwipePass

Pattern lock-based authentication has been widely adopted in modern smartphones. However, this scheme relies essentially on passwords, making it vulnerable to various side-channel attacks such as the smudge attack and the shoulder-surfing attack. In this paper, we propose a second-factor authentication system named SwipePass, which authenticates a smartphone user by examining the distinct physiological and behavioral characteristics embedded in the user's pattern lock process. By emitting and receiving modulated audio using the built-in modules of the smartphone, SwipePass can sense the entire unlocking process and extract discriminative features to authenticate the user from the signal variations associated with hand dynamics. Moreover, to alleviate the burden of data collection in the user enrollment phase, we conduct an in-depth analysis of users' behaviors under different conditions and propose two augmentation techniques to significantly improve identification accuracy even when only a few training samples are available. Finally, we design a robust authentication model based on CNN-LSTM and One-Class SVM for user identification and spoofer detection. We implement SwipePass on three off-the-shelf smartphones and conduct extensive evaluations in different real-world scenarios. Experiments involving 36 participants show that SwipePass achieves an average identification accuracy of 96.8% while maintaining a false accept rate below 0.45% against various attacks.

COVID-19 Crisis and Indian Kirana Shopkeeper’s Business Continuity and Sustainability Initiatives: Study During the First Unlock Stage

This research study ascertained how street corner small shops (called kirana shops in India) in Indian urban landscape adopted resource-based view (RBV) and dynamic capabilities view (DCV) perspectives to strategize regarding unlocking initiatives, process, operational change, and business continuance post COVID-19 pandemic and economic lockdown. The authors used qualitative research method with a semi-structured open-ended questionnaire to collect the data. Thematic content analysis was applied for data analysis. The data was collected in June 2020 in India when the initial unlock process was going on. The application of Situation Actor Process–Learning Action Performance (SAP-LAP) framework in conjunction with strategic management theories such as RBV and DCV provided a holistic understanding of the phenomenon. This study was also a demonstration of how a critical crisis situation like COVID-19 could relate to the SAP-LAP framework. The author found that shopkeepers developed new sets of valuable and rare and inimitable resources and capabilities. While all the aspects of sensing, seizing, and reconfiguration were attained to while devising the shops reopening strategies, new sets of resources and capabilities to attend to customers were also developed.

Motion Reliability Analysis of Unlocking Trigger Device Based on CPSO-BR-BP Neural Network with Uncertain Parameters

Aiming at overcoming the problem that the mechanism function of the unlocking trigger device is difficult to obtain and the corresponding reliability analysis cannot be performed, a motion reliability analysis method based on the CPSO-BR-BP neural network proxy model is proposed. Firstly, the particle swarm algorithm is optimized through the chaotic sequence, and the back-propagation (BP) neural network is optimized using Chaos Particle Swarm Optimization (CPSO) and Bayesian Regularization (BR) algorithm. The CPSO-BR-BP neural network proxy model is established, and the reliability of shape memory alloys (SMA) wire unlocking based on the structural function is calculated. Moreover, according to the structural function of the separation process, the motion reliability based on the proxy model and the improved membership function is calculated. Finally, a series reliability model is established based on the unlocking process and the separation process to calculate the reliability of the whole machine. The reliability of the unlocking trigger device is analyzed by the proposed method. Results show that the proposed method is computationally efficient with the calculated reliability of 0.9987.

Mobility change in Delhi due to COVID and its’ immediate and long term impact on demand with intervened non motorized transport friendly infrastructural policies

The COVID pandemic severely impacted mobility during lockdown as well as the period after that observing different phases of unlocking process. Lockdown has resulted in drastic mobility reduction and subsequent unlocking process brought back mobility gradually to a certain level, substantially lower than the Pre-COVID periods. However, this is expected to be back gradually to same level of Pre-COVID after certain period of time. While this change is planned to be gradual, it creates an opportunity to improve mobility towards non-motorized transport (NMT) which can influence travel behavior for present as well for the future covering Pre and Post-COVID periods. Apart from studying the influencing travel behavior during Pre and Post-COVID conditions, change in quantum of commuting population is required to be studied for various estimations related to transport planning. This quantum of commuting population is largely affected by the adopted locking/unlocking strategies by Government of India. Commuting population and travel behavior got influenced by the large migration from metro cities to smaller towns, adopted work from home (WFH) styles, reduced commute of elderly and children and other restrictions on gatherings, etc. Considering the range of allowed activities, influenced by the phases of locking/unlocking strategies, twelve different scenarios have been developed for various estimations. The developed scenarios have been named with alpha numeric style ranging from A0 to E5. A0 presenting the Pre-COVID scenario. Alphabet “A” represent Pre-COVID scenario, “B”, “C”, “D” and “E” Scenarios represent the unlocking phases, while number 1, 2, 3, 4 and 5 represents the different policy aspects related to the change on capacity of transport services (i.e. public transport capacity and change due to infrastructural improvement for NMT). Scenario A0 represents the Pre-COVID situation, while other ranges (viz., B1, B2, B3, C2, C3, C4, D2, D3, D5) represents various locking/unlocking levels. The Scenario E5 represents the situation without any movement restrictions, where public transport systems are assumed to be functioning with full capacity and infrastructure has been improved for NMT trips. Estimations for all the 12 scenarios include commuting population, their modal split, vehicle kilometers travelled by these vehicles and corresponding vehicular emission. Estimated modal split also includes the influence of improved NMT friendly infrastructure and reduced capacity of public transport systems. The results of developed scenarios provide a handy information for the policy makers to choose right policy to promote sustainable transportation with adequate emphasis on NMT. It is evident that as compared to the Pre-COVID scenario (A0), Post-COVID scenario with improved NMT infrastructure (E5) has VKT reduction of 19% in MTWs, 5% in Cars and 49% in Buses. Increase in bicycle trips have been estimated to be 5.88 million for Post-COVID scenario as compared to 1.1 million trips estimated for the Pre-COVID Scenario. Similar trend has also been observed for fuel consumption (reduction of 4.7%–11.8%) and corresponding vehicular emission (reduction of 14%). This study estimated the potential benefits of providing NMT friendly infrastructure considering the gradual shift influenced by locking/unlocking phases of COVID pandemic.

A Review on Smart Pendent

The world is facing a dangerous pandemic and it is a transmissible virus that infects people who came in contact with the infected person and with the things used by them. Many industries see huge economic losses, and businesses are going ruined. Although, unlock process is started still many industries facing problems due to the increasing rate of Covid positive patients, it is not possible to close working after the detection of individual positive employees. Also, it is difficult to find contacted employees with Covid positive employees. .It became a challenging task to find out how many people came in contact with the infected people. So, to make this process somehow easy we have designed a small device. In this paper, we have described the smart pendent a small device that helps to detect how many people come in contact with the coronavirus infected person. It is a wearable RF device in the form factor of a Pendant, suitable for powering a smart Rf device. An experimental comparison between multistage Cockcroft-Walton and Dickson RF-DC converters shows that the Dickson topology offers higher efficiency at high input power, whereas the Cockcroft- Walton converter performs better for low input power. The pendant can produce up to 23.2 µW at 10.4 m from a commercial isotropic 3 W RF power transmitter.

Fine-Grained and Context-Aware Behavioral Biometrics for Pattern Lock on Smartphones

Pattern lock has been widely used in smartphones as a simple and effective authentication mechanism, which however is shown to be vulnerable to various attacks. In this paper, we design a novel authentication system for more secure pattern unlocking on smartphones. The basic idea is to utilize various behavior information of the user during pattern unlocking as additional authentication fingerprints, so that even if the pattern password is leaked to an attacker, the system remains safe and protected. To accommodate a variety of user contexts by our system, a context-aware module is proposed to distinguish any of such contexts (e.g., body postures when drawing the pattern) and use it to guide the authentication. Moreover, we design a polyline weighted strategy with overlapping based on the consistency of pattern lock, which analyzes the behavior information of the user during the unlock process in a fine-grained manner and takes an overall consideration the results of different polylines. Based on 14,850 samples collected from 77 participants, we have extensively evaluated the proposed system. The results demonstrate that it outperforms state-of-the-art implicit authentication based pattern lock approaches, and that each key module in our system is effective.

Scalable Logic Circuits with Multiple Outputs and an Automatic Reset Function Based on DNAzyme-Mediated Branch Migration.

A scalable logic platform made up of multilayer DNA circuits was constructed using Pb2+, Cu2+, and Zn2+ as the three inputs and three different fluorescent signals as the outputs. DNAzyme-guided cyclic cleavage reactions and DNA toehold-mediated strand branch migration were utilized to organize and connect nucleic acid probes for building the high-level logic architecture. The sequence communications between each circuit enable the logic network to work as a keypad lock, which is an information protection model at the molecular level. The multi-output mode was used to monitor the gradual unlocking process of the security system, from which one can determine which password is correct or not immediately. The autocatalytic cleavage of DNAzyme makes the biocomputing circuit feasible to realize the reset function automatically without external stimuli. Importantly, the logic platform is robust and can work effectively even in complex environmental samples.

Covid-19 Transmission Dynamics During the Unlock Phase and Significance of Testing

The pandemic disease Covid-19 caused by SARS-COV-2 has established itself as the most devastating disease in the history of infectious disease, affecting 216 countries/territories across the globe. Policies like social distancing and lockdown were adopted to tackle the spreading of the disease. The disease is still not under control, but many countries have withdrawn the lockdown and going through phase-wise unlock-ing process. The removal of movement restriction causes free circulation of the disease mostly through the undetected class. The present study is an attempt to understand and estimate the possible epidemic burden during the unlock phase in the presence of the undetected class. Through a modified SEIR model, we focus our study on India and the USA, where the epidemic curve is still growing and the unlock process has started. We estimated the parameter values for both the countries using available data and used them to calculate the basic reproduction number. We also performed a global sensitivity analysis to search for the most sensitive parameters which can significantly change the dynamics of the disease. We observed that the use of repurposing drugs may further decrease the infected cases and help the disease controlling process. Our results emphasize on the implementation of 3T principles, trace, test, and treat, to contain the epidemic. The significance of large-scale testing in restricting the spread of infection during the unlock phase is evident for both India and the USA though they have different socio-economic conditions.

COVID-19 Pandemic as a Set of Economic Shocks in India:A Short Note

Socio-economic events that fall largely outside the purview of the direct control of a given economic agent allow much more rigorous quantitative modelling of effects that such events may have on that economic agent’s decision-making and the consequent economic outcomes. The on-going Corona pandemic across the Globe presents a unique case study to extract operationally exogenous shocks that can be subjected to further rigorous research as well as to help students learn about applied economics using real-time events rather than abstract theoretical generalizations. This pandemic has thrown a huge challenge for the largest democracy in the World, namely India. The subsequent series of lockdowns in India and the consequent unlocking process have given rise to several economic shocks that require urgent attention from both the academic and policy-making circles. An overview of the microeconomic and macroeconomic events that have been sparked by the current pandemic and, the several rounds of lockdowns and social unlocking, can help the policy makers to better understand how future policy interventions can improve economic outcomes in the post-COVID era. A brief overview of various such economic shocks and their implications are highlighted in this note. The aim is to highlight the most important economic concerns so as to motivate teaching and research that is driven by real-time concerns and that can shed more light on the ways in which people and institutions react to such a crisis with some indications on the possible road ahead.

Design and Development of an IoT & Raspberry Pi Based Smart Mirror

There is never an end to the devices that can be made smarter and smarter with the help of the adequate technology. There are a lot of smart display devices but mirrors provide an interactive environment while displaying these information’s. This paper presents the design and the development of a Smart mirror using raspberry pi with some additional features which provides face recognition for security and smart unlocking process. The contents are displayed on an LED monitor who is enclosed in a wooden frame and covered with a sheet of reflective one way mirror. The mirror provides basic detail like time, news details, weather of a city and display current message. All the computing is done with the help of a raspberry pi.

Fracture Failure Analysis of C110 Oil Tube in a Western Oil Field

There was an oil pipeline fracture found in the unlock process of Z well in western oilfield.The reason that made the oil tube fracturewassystematically studied usingmacroscopic analysis,physical and chemical property test,scanning electron microscope with an energy dispersive X-ray spectrometer and X-ray diffraction analysis.The results suggested that the requirement of relevant standard for C110 steel grade was satisfied with the chemical component and mechanical property of oil tube.The perforation of oil tube made H2S in the fluid medium enter the oil set of connected rings. In addition, the high-pressure gas left by gas contained certain H2S and O2 so that the tubewould fracture and be invalid under the combined action of sulfide stress corrosion and oxygen corrosion.

Self-locking mechanism for variable stiffness rigid–soft gripper

Pneumatic soft grippers made of silicone have been successfully applied in the industrial field of grabbing fragile objects. But their inherent low stiffness often limits the practical application in scenarios required high stiffness or large load capacity. To expand the application of soft grippers, a self-locking mechanism realized by an exoskeleton structure is proposed in this work. The stiffness, load carrying capacity, and grabbing stability of this soft–rigid grippers can be enhanced in the premise of maintaining sufficient compliance. The resulted rigid–soft gripper has the ability of tuning its stiffness, simply by locking and unlocking the ratchet-and-pawl of the exoskeleton structure. The locking process is automatically implemented with the bending deformation of soft gripper, and the unlocking process is realized quickly by a simple pneumatic unlocking actuator. The stiffness, grasping motion and output force of the gripper are experimentally characterized theoretically and experimentally. And the capability of unlocking actuators is also verified and tested. Experimental results demonstrate that the rigid–soft gripper has a load capacity up to 9 kg. The gripper can achieve quick, flexible and reliable grasping for objects of various dimensions and shapes, with no compressed gas needed for holding. The proposed self-locking mechanism provides a simple but effective method to enhance the performance of soft grippers and simplify the operation for variable-stiffness grasping.

Expand the Shares Together: Envy-Free Mechanisms with a Small Number of Cuts

We study the problem of fair division of a heterogeneous resource among strategic players. Given a divisible heterogeneous cake, we wish to divide the cake among n players to meet these conditions: (I) every player (weakly) prefers his allocated cake to any other player’s share (such notion is known as envy-freeness), (II) the allocation is dominant strategy-proof (truthful) (III) the number of cuts made on the cake is small. We provide methods for dividing the cake under different assumptions on the valuation functions of the players. First, we suppose that the valuation function of every player is a single interval with a special property, namely ordering property. For this case, we propose a process called expansion process and show that it results in an envy-free and truthful allocation that cuts the cake into exactly n pieces. Next, we remove the ordering restriction and show that for this case, an extended form of the expansion process, called expansion process with unlocking yields an envy-free allocation of the cake with at most $$2(n-1)$$ cuts. Furthermore, we show that in the expansion process with unlocking, the players may misrepresent their valuations to earn more share. In addition, we use a more complex form of the expansion process with unlocking to obtain an envy-free and truthful allocation that cuts the cake in at most $$2(n-1)$$ locations. We also, evaluate our expansion method in practice. In the empirical results, we compare the number of cuts made by our method to the number of cuts in the optimal solution ( $$n-1$$ ). The experiments reveal that the number of cuts made by the expansion and unlocking process for envy-free division of the cake is very close to the optimal solution. Finally, we study piecewise constant and piecewise uniform valuation functions with m pieces and present the conditions, under which a generalized form of expansion process can allocate the cake via O(nm) cuts.

Numerical study on separation shock characteristics of pyrotechnic separation nuts

This paper establishes a finite element model of pyrotechnic separation nuts and simulates the whole separation process based on the explicit dynamic codes LS-dyna with Arbitrary Lagrange-Euler (ALE) algorithm. The separation shock generated in the unlocking process is analyzed in detail and the results reveal that the pyrotechnic explosion shock and strain energy shock are two sources for the whole separation shock. Besides that, the influence of prestress on the separation shock and its two shock sources is also researched. The results show that the prestress could strengthen all three shocks, especially the strain energy release shock. This paper also compares the shock response spectrum (SRS) of the three shocks and finds that the SRS of separation shock is equal to the envelope of the SRS of pyrotechnic explosion shock and strain energy release shock. In the model of this paper, the pyrotechnic explosion shock plays a dominant role in the frequency range of 100 Hz to 10 KHz. The conclusions got in this work are helpful to insight the mechanism of separation shock and can provide a reference for the design of separation nuts.

Slow Unlocking Processes Preceding the 2015 Mw 8.4 Illapel, Chile, Earthquake

AbstractOn 16 September 2015, the Mw 8.4 Illapel earthquake occurred in central Chile with no intense foreshock sequences documented in the regional earthquake catalog. Here we employ the matched‐filter technique based on an enhanced template data set of previously catalogued events. We perform a continuous search over an ~4‐year period before the Illapel mainshock to recover the uncatalogued small events and repeating earthquakes. Repeating earthquakes are found both to the north and south of the mainshock rupture zone. To the south of the rupture zone, the seismicity and repeater‐inferred aseismic slip progressively accelerate around the Illapel epicenter starting from ~140 days before the mainshock. This may indicate an unlocking process involving the interplay of seismic and aseismic slip. The acceleration culminates in a M 5.3 event of low‐angle thrust mechanism, which occurred ~36 days before the Mw 8.4 mainshock. It is then followed by a relative quiescence in seismicity until the mainshock occurred. This quiescence might correspond to an intermediate period of stable slip before rupture initiation. In addition, to the north of the mainshock rupture area, the last aseismic‐slip episode occurs within ~175–95 days before the mainshock and accumulates the largest amount of slip in the observation period. The simultaneous occurrence of aseismic‐slip transients over a large area is consistent with large‐scale slow unlocking processes preceding the Illapel mainshock.