Unpredictable Environmental Changes Research Articles

Security Enhancements over AODV Using Multi-hop Acknowledgment

In most applications of Mobile Ad-hoc Networking and Wireless Sensor networks (WSNs), security and power consumption is a recurring problem which is very difficult to solve due to unpredictable behaviour, environmental changes and mobility of nodes. TERP is a Trust based Energy Routing Protocol that considers the energy conservation and security aspects of WSNs. It is an improved version of AODV and ensures low power consumption while adding a trust based system to the reactive nature of AODV. It also provides the solutions for the most basic attacks like node selfishness, spoofing, misbehaviour and packet sniffing. But black-hole attack, gray-hole attack, Sybil and wormhole attacks are yet to be addressed in the TERP. This paper provides a solution to detect and prevent the node misbehaviour and gray-hole attack. TERP identifies the node misbehaviour using direct and indirect trust recommendations received from neighbour nodes. The detection rate of misbehaving nodes is less during the initial life of the network. Therefore we propose a method that detects the node misbehaviour during the initial life by using a multi-hop acknowledgement system. The simulation results show that the proposed method performs well in detecting the gray-hole and node misbehaviour.

Assessment for INS/GNSS/Odometer/Barometer Integration in Loosely-Coupled and Tightly-Coupled Scheme in a GNSS-Degraded Environment

With the increasing demands for seamless landvehicle navigation, systems with robust performance are required in highly urbanized areas. The traditional INS/GNSS integration is widely applied to solve this issue. However, the system still suffers from bad GNSS signal reception and INS time accumulated errors that seamlessness and stability are difficult to maintain. In this study, the performance of the low cost INS/GNSS with aiding sensors, such as an odometer and barometer, was evaluated for both the loosely-coupled (LC) scheme and tightly-coupled (TC) scheme. Moreover, considering barometric error accumulation, a vehicle-behavior based drift control method has been proposed. An experiment was conducted under harsh GNSS-degraded scenarios to assess the characteristics and performance for different sensor combinations, using single constellation (GPS) with single-frequency (L1 band) measurement. Overall, the TC scheme without additional strategies in detecting abnormal measurement encounters more challenges to achieve stable performance. In an INS/GNSS/barometer system with the proposed drift control method, error accumulation under unpredictable environmental changes was successfully mitigated in both schemes. The proposed method can maintain a height accuracy of 2-meter level root mean square even after a long term operation. In an INS/GNSS/odometer combination, improvements were observed in the horizontal and vertical direction for both schemes. According to statistical analysis, an INS/GNSS/odometer/barometercombination shows 16.57% and 6.11% in the horizontal, and 30.71% and 71.28% in the vertical for the LC scheme and TC scheme, compared with an INS/GNSS combination.

Paradigm Shift in Business Education: A Competence-Based Approach

The fast and unpredictable changes in the business environment lead to significant changes in the future job market. For current business students, the future will offer many new opportunities for their employment but, at the same time, it will also create many threats disguised in the disappearing jobs. Business education centered mainly on knowledge transmission is challenged to switch towards a competence-based approach which includes knowledge, skills, and attitudes. The present research focuses on the need to change the paradigm of business education by creating a new learning environment centered on business competencies, and on a new knowledge ecosystem dynamics. The approach uses both qualitative and quantitative methods. In the first phase the research is focused on a critical literature review, and extraction of ideas for the next phase based on quantitative methods. In order to evaluate the students’ perception on the need of competence-based business education, a questionnaire has been designed and applied to undergraduate and graduate students enrolled in business and management programs. Data is processed by using SPSS and deriving six logistic regressions based on the conceptual model designed similar to a hierarchy Findings coming from students show a significant awareness for the need of paradigm shift in business education, from knowledge transfer to business competence development.

Ethnobotany of suweg (Amorphophallus paeoniifolius): Folk classification, habitat, and traditional conservation in Cisoka Village, Majalengka District, Cimanuk Watershed Region, Indonesia

Abstract. Mutaqin AZ, Kurniadie D, Iskandar J, Nurzaman M, Partasasmita R. 2020. Ethnobotany of suweg (Amorphophallus paeoniifolius): Folk classification, habitat, and traditional conservation in Cisoka Village, Majalengka District, Cimanuk Watershed Region, Indonesia. Biodiversitas 21: 546-555. Amorphophallus paeoniifolius (Dennst.) Nicolson or suweg is commonly called in Sunadese of West Java as suweg that is a species of tuber growing in many regions of the world, including in the Cimanuk Watershed, West Java Province, Indonesia. A. paeoniifolius usually grows in rural areas of West Java in some agroecosystem types, including the homegarden, garden, and mixed garden system. This plant species, in contrast to other tuber species, such as taro, has not been intensively cultivated by rural community in West Java. Even though A. paeoniifolius has not been intensively cultivated, this plant species in the future have the potential to be used for various purposes for human being. Because A. paeoniifolius, one of plant tubers, has a high resistance to unpredictable environmental changes, such as climate change, pest disruption, and easy to maintain. This study aimed to elucidate the traditional ecological knowledge (TEK) of rural people of Cisoka Village, Cikijing Sub-district, Majalengka District of Cimanuk Watershed, West Java on folk classification, habitat, and traditional conservation of A. paeoniifolius. The method used in this study was qualitative. Field data collection was undertaken by observation and semi-structured interviews or deep interviews with competent informants. The results of study showed that the rural population of Cisoka Village, Majalengka District, has recognized two kinds of Amorphophallus. Firstly, Amorphophallus is a commonly consumed that is called suweg which has scientific name as Amorphophallus paeoniifolius (Dennst.) Nicolson. Secondly, Amorphophallus is recognized as not commonly consumed which is called 'iles-iles' (Amorphophallus variabilis Blume). Both species can be traditionally classified based on morphology (tubers, leaf blade and petioles, and flowers), habitat, utilization, cultivation, and suitability of growing places. Specifically, A. paeoniifolius, grows in various conditions, growing at non-cultivated lands, such as forests and cultivated land, such as homegarden, garden, mixed-garden, and rice fields, or pond edges, but predominantly grows in homegardens and gardens. Some of these lands are hieum or shaded areas and negrak or open areas. A. paeoniifolius starts to grow and develop at the beginning of the rainy season until approaching the dry season, which is characterized by yellowing and falling of petiole. Conservation of A. paeoniifolius has been based on tradition is carried out by the rural community through storage/ preparation of seeds, which does not destroy A. paeoniifolius that grows in several types of agroecosystems, and is managed semi-intensively in several types of agroecosystems such as homegardens and gardens.

К ВОПРОСУ О НЕОБХОДИМОСТИ ВНЕДРЕНИЯ СИСТЕМНОГО ПОДХОДА К РАССМОТРЕНИЮ ДЕЛ ОБ ИЗМЕНЕНИИ ЛИБО РАСТОРЖЕНИИ ГРАЖДАНСКО-ПРАВОВЫХ ДОГОВОРОВ

For the Russian reality, the stability and stability of the execution of transactions and obligations in the context of frequent and unpredictable changes in the external environment is becoming an increasingly important component of economic and legal relations. Modern civil legislation, on the one hand, guarantees the stability of existing legal relations, on the other, allows for the modification and termination of contracts both at the mutual desire of the parties, and in connection with the will of the other party, if it is granted such a right. The third option is a way to change or terminate the contract in court. However, at present, there are many subjective and objective circumstances that are not provided for by the parties when concluding the contract, which make it difficult or even impossible to continue performing obligations under it while maintaining the conditions that were originally laid down in it. Not always resolving of such situations envisaged by the legislator, but because there are situations when the parties relations are further complicated by the inability to quickly and effectively solve the current conflict, especially if parties are business entities and any delay can lead to significant financial costs not only of the parties of legal relations, but also third parties whose rights are directly or indirectly affected.

A Quantitative Analysis of Risk Premia in the Corporate Bond Market

Measures of corporate credit risk incorporate compensation for unpredictable future changes in the credit environment and compensation for expected default losses. Since the launch of purchases of government securities and corporate securities by the European Central Bank, it has been discussed whether the observed reduction in corporate credit risk was due to the decrease in risk aversion favored by the monetary easing or by expectations of lower losses due to corporate defaults. This work introduces a new methodology to break down the factors that drive corporate credit risk, namely the premium linked to cyclical and monetary conditions and that linked to the restructuring of the companies. Untangling these two components makes it possible to quantify the drivers of excess returns in the corporate bond market.

Model framework for emergence of synchronized oscillations

Autonomy is an important concept when investigating the mechanism whereby biological systems exhibit flexibility against unpredictable environmental changes. Herein we propose a parameter-tuning algorithm, based on a selection principle, that allows the emergence of synchronization between populations of oscillators through autonomous changes of the intrinsic parameters. With the algorithm, the populations exhibit self-recovery of the synchronized state after the existing synchronized state is broken suddenly; that is, the system chooses appropriate values of the intrinsic parameters to recover the synchronized state. We also propose a continuous model in which the selection is described by the replicator model and the parameter values are determined by the density profile of the oscillators in parameter space.

Graphene-Grid Deployment in Energy Harvesting Cooperative Wireless Sensor Networks for Green IoT

Energy harvesting (EH) technology is an effective way to resolve the energy supply problem for green Internet of Things application. However, it is extremely vulnerable to the unpredictable environmental changes, and as a result, sensor nodes are charged in an uncontrollable way. In this paper, we focus on EH cooperative wireless sensor networks (EHC-WSNs), a new type of WSNs that integrates EH and wireless energy transfer technologies to provide the continuous and controllable energy supply. We propose the graphene-grid deployment strategy to guarantee energy coverage and network connectivity, whereby a Graphene-based Energy Cooperation Management (GECM) mechanism is designed under the energy-neutral operation. Furthermore, we divide GECM into two different phases, i.e., graphene-based energy cooperative charging strategy and graphene-based opportunistic cooperative routing algorithm, which are optimized according to the graphene-grid structure. Extensive simulations show that the proposed GECM can maximize the harvested energy utilization and prolong the network lifetime.

Specific quorum sensing molecules of ammonia oxidizers and their role during ammonium metabolism in Zhalong wetland, China

The primary challenge of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) surviving in wetlands are the rapid and unpredictable environmental changes. To adapt to a fluctuant environment, ammonia oxidizers have to communicate with each other via acyl-homoserine lactones (AHLs). In this study, AOA and AOB in the soil samples taken from Zhalong wetland were incubated. Dynamics of AHLs during the incubation of ammonia oxidizers were measured. Then, the specific AHLs of AOA and AOB were identified, respectively. The results showed that AOA secreted N-butyryl-dl-homoserine lactone (C4-HSL) and N-octanoyl-l-homoserine lactone (C8-HSL) to cope with nitrite accumulation, while they secreted N-(3-oxododecanoyl)-dl-homoserine lactone (OXOC12-HSL) to regulate their ammonium metabolism activity. AOB secreted N-hexanoyl-dl-homoserine lactone (C6-HSL), N-dodecanoyl-l-homoserine lactone (C12-HSL), N-tetradecanoyl-dl-homoserine lactone (C14-HSL) and N-(3-oxododecanoyl)-tetradecanoyl-dl-homoserine lactone (OXOC14-HSL) only to enhance the metabolism activity. The dominant AOA belonged to the Nitrososphaera lineage, while the dominant AOB grouped into the Nitrosomonas lineage. The AHLs receptor homologs were identified in both AOA and AOB, which confirmed that AOA and AOB had the QS system. The present work was the first study that elucidated the QS system of AOA and AOB in multidimensional, and confirmed the role of QS system in ammonia oxidizers' metabolism.

Shortsighted Evolution Constrains the Efficacy of Long-Term Bet Hedging.

To survive unpredictable environmental change, many organisms adopt bet-hedging strategies that are initially costly but provide a long-term fitness benefit. The temporal extent of these deferred fitness benefits determines whether bet-hedging organisms can survive long enough to realize them. In this article, we examine a model of microbial bet hedging in which there are two paths to extinction: unpredictable environmental change and demographic stochasticity. In temporally correlated environments, these drivers of extinction select for different switching strategies. Rapid phenotype switching ensures survival in the face of unpredictable environmental change, while slower-switching organisms become extinct. However, when both switching strategies are present in the same population, then demographic stochasticity-enforced by a limited population size-leads to extinction of the faster-switching organism. As a result, we find a novel form of evolutionary suicide whereby selection in a fluctuating environment can favor bet-hedging strategies that ultimately increase the risk of extinction. Population structures with multiple subpopulations and dispersal can reduce the risk of extinction from unpredictable environmental change and shift the balance so as to facilitate the evolution of slower-switching organisms.

Multi-robot coordination for connectivity recovery after unpredictable environment changes

Abstract In the present paper we develop a distributed method to reconnect a multi-robot team after connectivity failures, caused by unpredictable environment changes, i.e. appearance of new obstacles. After the changes, the team is divided into different groups of robots. The groups have a limited communication range and only a partial information in their field of view about the current scenario. Their objective is to form a chain from a static base station to a goal location. In the proposed distributed replanning approach, the robots predict new plans for the other groups from the new observed information by each robot in the changed scenario, to restore the connectivity with a base station and reach the initial joint objective. If a solution exists, the method achieves the reconnection of all the groups in a unique chain. The proposed method is compared with other two cases: 1) when all the agents have full information of the environment, and 2) when some robots must move to reach other waiting robots for reconnection. Numerical simulations are provided to evaluate the proposed approach in the presence of unpredictable scenario changes.

Modeling ‘ilities’ in early Product-Service Systems design

Product-Service Systems, like all complex systems, are vulnerable to unpredictable environmental changes that can seriously undermine their ability to continuously deliver value to customers. The long-term consequences of volatile markets, unanticipated technologies, and unpredictable changes in society must be captured, modeled and communicated to decision makers since the earliest stages of the design, so to identify sustainable PSS solutions able to deliver value for years or decades to come. The paper analyses the problem of PSS changeability from the perspective of established medium-large product manufacturers facing the transition toward result-oriented PSS offers. Building on established literature in the systems engineering field, the paper proposes the definition of the changeability criteria, also named ‘ilities’, that are relevant to consider for PSS engineers in the early stages of design. Furthermore, the paper describes a systematic framework for assessing ilities in early PSS design, elaborating on technological enablers for ilities modeling.

Antithetic proportional-integral feedback for reduced variance and improved control performance of stochastic reaction networks.

The ability of a cell to regulate and adapt its internal state in response to unpredictable environmental changes is called homeostasis and this ability is crucial for the cell's survival and proper functioning. Understanding how cells can achieve homeostasis, despite the intrinsic noise or randomness in their dynamics, is fundamentally important for both systems and synthetic biology. In this context, a significant development is the proposed antithetic integral feedback (AIF) motif, which is found in natural systems, and is known to ensure robust perfect adaptation for the mean dynamics of a given molecular species involved in a complex stochastic biomolecular reaction network. From the standpoint of applications, one drawback of this motif is that it often leads to an increased cell-to-cell heterogeneity or variance when compared to a constitutive (i.e. open-loop) control strategy. Our goal in this paper is to show that this performance deterioration can be countered by combining the AIF motif and a negative feedback strategy. Using a tailored moment closure method, we derive approximate expressions for the stationary variance for the controlled network that demonstrate that increasing the strength of the negative feedback can indeed decrease the variance, sometimes even below its constitutive level. Numerical results verify the accuracy of these results and we illustrate them by considering three biomolecular networks with two types of negative feedback strategies. Our computational analysis indicates that there is a trade-off between the speed of the settling-time of the mean trajectories and the stationary variance of the controlled species; i.e. smaller variance is associated with larger settling-time.

Effects of Tank Gun Structural Components on the First Shot Hit Probability

Fire power for a main battle tank is one of the most important performance parameters like survivability and mobility. Fire power effectiveness is directly related to the first shot hit probability, performance of main gun, second armament, gun and turret drive system, fire control system, automatic target tracker, commander and gunner sight etc. First shot hit probability (a measure of cumulative effects of errors) is affected by the variations of the projectile parameters, the main gun structure uncertainties, fire control system errors, interaction between the projectile and the gun barrel and the unpredictable environmental changes. These errors and variations can be eliminated or minimised by understanding and simulating the firing event properly, manufacturing the related parts in high precision, using advanced fire control algorithms, and accurate sensors. In this review study, the effects of main gun structural components on the first shot hit probability are investigated taking into account all of the associated error sources. In order for a main battle tank to have both high and repetitive first shot hit probability under all battlefield conditions the gun structure should respond in a similar manner in successive firings without causing any abrupt change in performance. In this study, first the dynamic behaviour of gun/projectile system is discussed and then the design recommendations for the main gun components such as bearings, gun barrel, recoil system etc. to achieve higher first shot hit probability are reviewed.

Designing Efficient Reconfigurable Control Systems Using IEC61499 and Symbolic Model Checking

IEC 61499 provides a standardized approach for the development of distributed control systems. The standard introduces a component architecture, based on function blocks that are event-triggered components processing data and signals. However, it gives only limited support for the design of reconfigurable architectures. In particular, handling of several reconfiguration scenarios is quite heavy on this level since a scenario changes the execution model of the system due to requirements. To this end, a new IEC 61499-based model named reconfigurable function blocks (RFBs) is proposed. An RFB processes the reconfiguration events and switches directly to the suitable configuration using a hierarchical state machine model. The latter represents the reconfiguration model which reacts on changes in the environment in order to find an adequate reconfiguration scenario to be executed. Each scenario presents a particular sequence of algorithms, encapsulated in another execution control chart slave which represents the control model of an RFB. This hierarchy simplifies the design and separates the reconfiguration logic from control models. To verify its correctness and alleviate its state space explosion problem in model checking, this paper translates an RFB system automatically into a generalized model of reconfigurable timed net condition/event systems (GR-TNCES), a Petri net class that preserves the semantics of an RFB system. In this paper, along with verification of deterministic properties, we also propose to quantify and analyze some probabilistic properties. As a case study, we consider a smart-grid system, interpreting permanent faults in it as reconfiguration events, and we characterize them with the expected occurrence probability and the corresponding repair time. A tool chain ZiZo is developed to support the proposed approach. Note to Practitioners —For reconfigurable distributed control systems, two models are indispensable: a control model that defines the hardware and software behaviors and a reconfiguration model that manages unpredictable changes in the related environment for configuring accordingly the system behavior. The proposed RFB approach is based on hierarchical state chart specification within function blocks, its automatic conversion to a reconfigurable Petri net GR-TNCES, which models all possible reconfiguration scenarios and a probabilistic model checking for qualitative and quantitative analysis. The system flexibility is ensured by a decision algorithm and a reconfiguration matrix which selects dynamically the right scenario to execute. The approach is supported by ZiZo tool chain which creates and edits reconfigurable function blocks model and converts it automatically to GR-TNCES, and then to specific PRISM models. The detection of the worst cases before deployment is a major virtue of the approach that practitioners need to estimate and enhance the design process. Several properties are easily checked and estimated such as system feasibility before and after reconfiguration, deadlock detection, confluence, estimation of the reconfiguration failure, system availability, and best repair time. The developed software package can be applied in any domain requiring flexibility and failure estimation, such as new medical technologies, transportation systems, smart and microgirds, and manufacturing systems.

Applications of temperature and humidity monitoring system at aerophonic plants based on IoT

Indonesian agricultural system has improved significantly along with technological developments. However, as a result of technological developments, agricultural land becomes narrow. To overcome the increasingly narrow farming land, start developing systems suitable for planting with aeroponic system. Unpredictable environmental climate changes can disrupt productivity growth and create low quality crops. To solve this problem, monitoring system based on Android needed. This system is used to monitor in parameters change, the parameters include temperature and humidity. Android-based monitoring system uses java programming and is open source, besides the user can monitor the development of spinach plants, by looking at data that has been stored into the database so that users can know the development of the plant. This application can be accessed via smartphone with android operating system as a client server.

Temperature-Resilient Time Synchronization for the Internet of Things

Networks deployed in real-world conditions have to cope with dynamic, unpredictable environmental temperature changes. These changes affect the clock rate on network nodes, and can cause faster clock de-synchronization compared to situations where devices are operating under stable temperature conditions. Wireless network protocols, such as time-slotted channel hopping (TSCH) from the IEEE 802.15.4-2015 standard, are affected by this problem, since they require tight clock synchronization among all nodes for the network to remain operational. This paper proposes a method for autonomously compensating temperature-dependent clock rate changes. After a calibration stage, nodes continuously perform temperature measurements to compensate for clock drifts at runtime. The method is implemented on low-power Internet of Things (IoT) nodes and evaluated through experiments in a temperature chamber, indoor and outdoor environments, as well as with numerical simulations. The results show that applying the method reduces the maximum synchronization error more than ten times. In this way, the method allows reduction in the total energy spent for time synchronization, which is practically relevant concern for low data rate, low energy budget TSCH networks, especially those exposed to environments with changing temperature.

A Quantitative Analysis of Risk Premia in the Corporate Bond Market

We propose an econometric model to decompose corporate bond spreads into compensation required by investors for unpredictable future changes in the credit environment and for expected default losses. We use the model to understand whether the significant reduction in corporate bond spreads observed since the launch of the CSPP (Corporate Sector Purchase Programme) is attributable more to the fact that expansionary monetary policy measures tend to increase the risk appetite of investors and compress risk premia, or to the ability of unconventional measures to reduce expected default losses by improving investors’ expectations about the economic and financial conditions of issuers.

Early transcriptional response pathways in Daphnia magna are coordinated in networks of crustacean-specific genes.

Natural habitats are exposed to an increasing number of environmental stressors that cause important ecological consequences. However, the multifarious nature of environmental change, the strength and the relative timing of each stressor largely limit our understanding of biological responses to environmental change. In particular, early response to unpredictable environmental change, critical to survival and fitness in later life stages, is largely uncharacterized. Here, we characterize the early transcriptional response of the keystone species Daphnia magna to twelve environmental perturbations, including biotic and abiotic stressors. We first perform a differential expression analysis aimed at identifying differential regulation of individual genes in response to stress. This preliminary analysis revealed that a few individual genes were responsive to environmental perturbations and they were modulated in a stressor and genotype-specific manner. Given the limited number of differentially regulated genes, we were unable to identify pathways involved in stress response. Hence, to gain a better understanding of the genetic and functional foundation of tolerance to multiple environmental stressors, we leveraged the correlative nature of networks and performed a weighted gene co-expression network analysis. We discovered that approximately one-third of the Daphnia genes, enriched for metabolism, cell signalling and general stress response, drives transcriptional early response to environmental stress and it is shared among genetic backgrounds. This initial response is followed by a genotype- and/or condition-specific transcriptional response with a strong genotype-by-environment interaction. Intriguingly, genotype- and condition-specific transcriptional response is found in genes not conserved beyond crustaceans, suggesting niche-specific adaptation.

The Effect of Discontinuous and Unpredictable Environmental Change on the Use of Management Accounting during Organizational Decline: A Field Study

This paper investigates whether and how organizations use management accounting during decline. Based on interviews and observation in five private sector organizations and one in the public sector, I employ a theoretical lens distinguishing the continuity and predictability of environmental change. I find that members in organizations facing decline due to a discontinuous and unpredictable environmental change leverage management accounting during decline. In contrast, members in organizations facing decline due to a continuous and predictable environmental change question the truth and value of their management accounting practices and, as a result, do not change their use of management accounting to manage decline. For those organizations that do leverage management accounting to manage decline, I employ a theoretical lens based on theory and research relating to the process of organizational learning. I find that organizational members first engage in a comprehensive review of their management accounting systems and reports to convince themselves that they can be relied upon. Following this process, they use accounting to understand the past, develop metrics intended to reach all employees, and institute various forms of accountability to support the management of decline. These uses of management accounting align with the information processing, interpretation, and dissemination activities of organizational learning, which enables organizations to find a new language for understanding and managing decline. My findings contribute to research and practice.