Bad Markings Research Articles

A Set Covering Approach to Design Maximally Permissive Supervisors for Flexible Manufacturing Systems

The supervisory control of Petri nets aims to enforce the undesired behavior as unreachable by designing a set of control places. This work presents a set cover approach to design maximally permissive supervisors. For each first-met bad marking, an integer linear programming problem is developed to obtain a control place to prohibit it. An objective function is formulated to make the maximal number of first-met bad markings forbidden. Then, we develop a set covering approach to minimize the number of selected control places. The proposed approach can guarantee the maximal permissiveness of the obtained supervisor and provide a trade-off between structural complexity and computational cost. Several examples are considered to validate the proposed method.

Kode Etik Profesi Notaris dalam Pelanggaran Pembuatan Akta Kepemilikan Saham

As long as a particular authentic deed cannot be made by another public official, the Notary is the public official who has the power to create it.. If a Notary ignores the honor and dignity of his position, violates general regulations, or makes other mistakes in carrying out his duties as a Notary, then supervision of the Notary is very important. So that this profession does not get bad marks from the public, as in the case that occurred on September 2 2022, a Notary named Oktaviana who acted carelessly in accepting the deed of shareholder decision statement whose contents could be detrimental to one of the parties. Apart from that, Notary Oktoviana is also suspected of siding with one of the parties so that he carried out the request to make deed number 6 dated 24 August and 13 September 2022 which resulted in huge losses for the other party.

A Huffman code LSB based image steganography technique using multi-level encryption and achromatic component of an image

In the recent couple of years, due to the accelerated popularity of the internet, various organizations such as government offices, military, private companies, etc. use different transferring methods for exchanging their information. The Internet has various benefits and some demerits, but the primary bad mark is security of information transmission over an unreliable network, and widely uses of images. So, Steganography is the state of the art of implanting a message in the cover objects, that nobody can suspect or identify it. Therefore, in the field of cover steganography, it is very critical to track down a mechanism for concealing data by utilizing different blends of compression strategies. Amplifying the payload limit, and robustness, and working on the visual quality are the vital factors of this research to make a reliable mechanism. Different cover steganography research strategies have been recommended, and each adores its benefits and impediments but there is a need to foster some better cover steganography implements to accomplish dependability between the essential model of cover steganography. To handle these issues, in this paper we proposed a method in view of Huffman code, Least Significant Bits (LSB) based cover steganography utilizing Multi-Level Encryption (MLE) and colorless part (HC-LSBIS-MLE-AC) of the picture. It also used different substitution and flicking concepts, MLE, Magic matrix, and achromatic concepts for proving the proficiency, and significance of the method. The algorithm was also statistically investigated based on some Statistical Assessment Metrics (SAM) such as Mean Square Error (MSE), Peak Signal Noise Ratio (PSNR), Normalized Cross Correlation (NCC), Structural Similarity Index Metric (SSIM), etc. and different perspectives. The observational outcomes show the likelihood of the proposed algorithm and the capacity to give unwavering quality between security, payload, perception, computation, and temper protection.

Robustness Analysis of Automated Manufacturing Systems With Unreliable Resources Using Petri Nets

This paper studies the maximally permissive robustness analysis of automated manufacturing systems (AMSs) with unreliable resources in the paradigm of Petri nets (PNs). Two types of robust markings, i.e., strongly robust markings and weakly robust markings, are defined in this paper. We propose robustness equivalence and non-robustness equivalence to characterize the markings that exhibit the same robustness and non-robustness, respectively. Reachability graph (or RG hereafter) is directly used to determine the robustness of markings; however, it is difficult to use in large-scale systems due to formidable computational difficulty. As an alternative, we present a reduced reachability graph (or R2G hereafter) based necessary and sufficient condition to check the robustness of markings, in terms of the liveness analysis of markings in R2G. We show that all safe markings of an R2G correspond to strongly robust markings of the corresponding RG, and deadlock markings as well as their bad markings and livelock markings as well as their bad markings of an R2G correspond to non-robust markings and weakly robust markings of the corresponding RG, respectively. Hence, the robustness of markings in an RG can be determined effectively and efficiently through the liveness analysis of markings in the corresponding R2G. Note to Practitioners—In practical manufacturing scenarios, it is urgent to analyze and control the automated manufacturing systems (AMSs) so as to ensure their continual production against any resource failure. If the failures of an AMS are not handled gracefully, the whole system may fall into a blocking. As a consequence, system production does not meet rapid manufacturing goals and objectives. In this paper, we focus on the maximally permissive robustness analysis of AMSs with unreliable resources in the paradigm of Petri nets. We define two types of robustness in terms of markings, i.e., strong robustness and weak robustness. From the viewpoint of reachability graph, we propose robustness equivalence and non-robustness equivalence among markings and present the procedures to check the robustness of markings. Furthermore, a set of necessary and sufficient conditions are established to provably ensure that the robustness of markings can be determined through liveness analysis in a reduced reachability graph. Therefore, the robustness of markings can be determined in a computationally efficient way.

Wellbeing, coping with homeschooling, and leisure behavior at different COVID-19-related lockdowns: A longitudinal study in 9- to 16-year-old German children.

BackgroundSchool closures are an effective measure against the spread of Covid‐19. However, they pose a major challenge to children, especially to those from socially disadvantaged families. The present study compared the wellbeing, coping with homeschooling, and leisure behavior of children and adolescents at two different periods of school closures in Germany. Wellbeing was also compared with wellbeing before the pandemic.MethodsWithin the framework of the cohort study LIFE Child, 152 9‐ to 16‐year‐old children completed online surveys on wellbeing (KIDSCREEN‐27 scales on physical wellbeing, psychological wellbeing, and peer and social support), coping with homeschooling (concentration, motivation, fun, mastering of schoolwork, fear of bad marks), and leisure behavior (TV time, computer gaming time, indoor physical activity) during two COVID‐19‐related lockdowns in March 2020 (t1) and in January 2021 (t2). Data from both time points were compared using mixed‐effect models. Wellbeing was additionally compared with the wellbeing in 2019, before COVID‐19 (t0). We also assessed the effects of the socio‐economic status (SES) on all outcomes and changes between time points.ResultsAll considered wellbeing scores declined significantly between t0 and t1. Physical wellbeing decreased further between t1 and t2, while social support increased. Coping with homeschooling degraded significantly between t1 and t2, while leisure behavior did not change significantly. Lower SES was associated with lower physical wellbeing, poorer coping with homeschooling, longer computer gaming times, and a stronger decrease of concentration on schoolwork from t1 to t2.ConclusionRepeated school closures have a negative effect on already compromised physical wellbeing and coping with homeschooling, especially in children from lower social strata.

Blockchain for Industry 4.0: A Far reaching Survey

Because of the multiplication of ICT during the most recent couple of many years, there is a dramatic expansion in the use of different brilliant applications, for example, shrewd cultivating, savvy medical care, production network and coordinated factors, business, the travel industry and friendliness, energy the executives and so forth Nonetheless, for all the previously mentioned applications, security and protection are main pressing issues keeping taking into account the use of the open channel, i.e., Web for information move. Albeit numerous security arrangements and guidelines have been proposed throughout the years to improve the security levels of previously mentioned brilliant applications, yet the current arrangements are either founded on the incorporated engineering (having weak link) or having high calculation and correspondence costs. Also, a large portion of the current security arrangements has focussed just on a couple of viewpoints and neglect to address adaptability, strength, information stockpiling, network dormancy, suitability, changelessness, and detectability. To deal with the previously mentioned issues, blockchain innovation can be one of the arrangements. Spurred from these realities, in this paper, we present an orderly audit of different blockchain-based arrangements and their pertinence in different Industry 4.0-based applications. Our commitments in this paper are in four creases. First and foremost, we investigated the present status of-the-craftsmanship arrangements in the blockchain innovation for shrewd applications. Then, at that point, we outlined the reference design utilized for the blockchain relevance in different Industry 4.0 applications. Then, at that point, benefits and bad marks of the customary security arrangements are additionally talked about in contrast with their countermeasures. At long last, we gave a correlation of existing blockchain-based security arrangements utilizing different boundaries to give profound bits of knowledge to the perusers about its appropriateness in different applications.

MUZIKA U SRPSKOM ANIMIRANOM FILMU U PERIODU 1949–1969.

Тhe aim of the paper is to understand the position of music in the Serbian animated film during the first two decades of organized production of this artistic type in socialist Yugo- slavia (1949-1969). It is about the period that begins with the creation of the first (post-war) Serbian animated film, Pupil and a Bad Mark, authored by Vera and Ljubiša Jocić (1949). In this regard, we used the historical method, the method of analysis and a case study. The paper first provides insights into the context of the emergence and stages of development of Ser- bian cinematographic animation, and looks at the problems of understanding the poetics and status of this art, position, and function of music in an animated film, and then turns to the selected titles. The works analyzed in this paper assume the anthological oeuvres of the most prominent names of Serbian animation of the said period (Vera and Ljubiša Jocić, Divna Jova- nović, Marijan Vajda, Slavko Marjanac, Nikola Majdak, Ivo Kušanić, Borislav Šajtinac); the selection, therefore, refers to the totality of the visual, cinematographic, and auditory qualities. The result of this research suggests a considerable range in terms of the relations between music and image, that is, the important position of music as a constituent of narration; reveal- ing the rapid rise of the then still young artistic domain on the Serbian cultural scene. It is important to point out that the research we have conducted is the first attempt to consider the position of music in the historical context of the art of animation in Serbia.

An Improved Synthesis Method Based on ILPP and Colored Petri Net for Liveness Enforcing Controller of Flexible Manufacturing Systems

Petri nets are used to design deadlock control strategies for flexible manufacturing systems (FMS), which typically involve the addition of monitors and the associated arcs to the FMS. The addition of several monitors and associated arcs to first constructed Petri net model significantly complicates the Petri net controller. This paper develops a two-step method for preventing deadlocks based on a colored Petri net and a structurally minimal approach that significantly reduces the number of monitors. In the first step, a vector covering technique is applied to generate a minimal covered sets of first-met bad markings (FBMs) and legal markings that are respectively smaller than the sets of FBMs and legal markings. At one iteration, place invariants (PIs) corresponding to monitors are constructed by solving an integer linear programming problem (ILPP) to prohibit the maximum number of FBMs, while allowing all legal markings in the minimal covering set. The purpose of the ILPP is to maximize the number of FBMs forbidden by the PIs. Then, based on a colored Petri net, all generated monitors are combined into a global control place. Therefore, a supervisor with minimal structural complexity can be constructed. The obtained net model is controlled after the addition of the designed supervisor. Two instances from the literature are considered to illustrate the proposed approach.

Paruman The Khemion Master: Learning Chemistry Periodic table with Trading Card game

The purpose of this research is to learn about how IP character can help students remembering their lesson. In this case we apply the research to a subject that majority students having difficulty to learn, it is chemistry. Some students say that chemistry is the hardest subject for them. Some say that the hardest part is to remember codes and elements on chemistry. Even they said it is the most boring subject, and usually they get a bad mark for it. Based on our survey, we find out that most of students having difficulties to study the subject using traditional method. They prefer to learn using graphics, because it is easier to remember the codes. For this case, we create a set of play card that can help students remembering the chemicals codes. Each card has a unique IP Character that resembles chemical element. Writers also add an element, which could make the chemistry lesson easier to understand, that is game. A game rule will be applied on the card game, and it will help student learned chemistry. And to make it more attractive and fun, we also try to put some technology to the game. Using a technology called Augment Reality, we try to engage students more.

Evaluation of transportation network in AL- Fallujah city

The city of Fallujah suffers from bad design in their network and it still dominated by the same pattern of the road and street network system that was produced by the previous stages of the development of the city, which is awaiting the necessary and appropriate solutions, which calls for planning to modernize the road network and streets in it that can accommodate the reality of the city’s condition and the proposed expansions for its subsequent urban growth. The transportation network in Fallujah city was chosen as a case study, the network was divided into roads and intersections, the evaluation included two main roads and eleven sectoral roads, eleven arterial roads, and twenty-five intersections. The network was evaluated in three stages, the first stage was traffic flow and service level, the second stage was evaluating the network in terms of road and intersections marking, while the third stage concerned with evaluating the network in terms of sustainability. The HCS 2010 program was applied to evaluate the first stage, while the second and third stages were evaluated based on the field survey. The results of the first stage showed that most parts of the network in the northern zone suffer from traffic problems and have a low level of service, while most parts of the network in the southern zone have a high service level and enjoy high traffic flow. Most parts of the network were suffered from bad marking, which causes many problems for the users of this network. Related to sustainability, we note a lack of interest on the part of designers or decision-makers. It was concluded that traffic solutions should be economically feasible for some parts of the network, which would lead to improving the network’s performance at the level of the three stages.

School-related stressors in adolescents from 21 countries: What is universal?

School stress is one of the most important stressors in adolescents around the world. This study tested the impact of region, age, gender, family structure, and school achievement on adolescents’ stress perception. In a cross-sectional design, 12.172 adolescents from 21 countries participated in the study. Adolescents from Central European and North American countries had generally quite low levels of school stress. Adolescents from Southern Europe exhibited the highest stress levels, but also adolescents from Latin America, the Middle East and Asian countries reported quite high levels of school-related stress. Rank 1 in many countries was the pressure to get the best marks. Additionally, the fear that differences in opinion with the teacher may result in bad marks and that the leaning material is too difficult or too boring were also important stressors, whereas rivalries among pupils seemed not to be a major problem. Adolescents from single-parent families experienced higher school-related stress than adolescents from two-parent families. The findings were discussed with respect to overall globalization and future insecurities, leading to universal stressors of adolescents in different parts of the world.

Deadlock-free Supervisor Design for Robotic Manufacturing Cells With Uncontrollable and Unobservable Events

In this paper, a deadlock prevention policy for robotic manufacturing cells with uncontrollable and unobservable events is proposed based on a Petri net formalism. First, a Petri net for the deadlock control of such systems is defined. Its admissible markings and first-met inadmissible markings (FIMs) are introduced. Next, place invariants are designed via an integer linear program (ILP) to survive all admissible markings and prohibit all FIMs, keeping the underlying system from reaching deadlocks, livelocks, bad markings, and the markings that may evolve into them by firing uncontrollable transitions. ILP also ensures that the obtained deadlock-free supervisor does not observe any unobservable transition. In addition, the supervisor is guaranteed to be admissible and structurally minimal in terms of both control places and added arcs. The condition under which the supervisor is maximally permissive in behavior is given. Finally, experimental results with the proposed method and existing ones are given to show its effectiveness.

Enhancement of Computational Efficiency in Seeking Liveness-Enforcing Supervisors for Advanced Flexible Manufacturing Systems with Deadlock States

In industry 4.0, all kinds of intelligent workstations are designed for use in manufacturing industries. Among them, flexible manufacturing systems (FMSs) use smart robots to achieve their production capacity under the condition of a high degree of resources sharing. As a result, deadlock states usually appear unexpectedly. For solving the damage deadlock problem, many pioneers have proposed new policies. However, it is very difficult to make systems maximally permissive even if their policies can solve the deadlock problem of FMSs. According to our survey, the Maximal number of Forbidding First Bad Marking (FBM) Problems (MFFP) seems to be the best technology to obtain systems’ maximally permissive states in the existing literature. More importantly, the number of added control places (CP) is the smallest among the existing research works. However, when the complexity of a flexible manufacturing system increases, the computational burden rises rapidly. To reduce computational cost, we define a new concept named Pre Idle Places (PIP) to enhance the computational efficiency in Seeking Liveness-Enforcing Supervisors. We can bypass all PIP once they can be identified from a deadlock system under the process of solving MFFP. According to the data showed in three classical examples, our proposed Improved MFFP is better than conventional MFFP in terms of computational efficiency with the same controllers.

A Deadlock Prevention Policy for a Class of Multithreaded Software

Deadlock is an undesired situation in multithreaded software since it can lead to the stoppage of software. This paper studies the problem of deadlock control of multithreaded software based on Gadara nets, which are well studied for modelling concurrent programs. In particular, an iterative deadlock prevention policy based on siphons is proposed for a class of ordinary Gadara nets where the initial marking of each idle place is one. At each iteration, we compute emptiable siphons containing the smallest number of resource places. Then, bad markings are computed based on these siphons. On the basis of the bad markings, a constraint is constructed that forbids not only bad markings that empty one of the siphons but also some other bad markings. The algorithm is carried out until no emptiable siphon exists in the net. Compared with the existing methods, the resultant net derived from the proposed method is live and maximally permissive with a simpler supervisor. Finally, two examples are provided to illustrate the proposed deadlock prevention policy.

Partial Reachability Graph Analysis of Petri Nets for Flexible Manufacturing Systems

Petri nets are an important and popular tool to model and analyze deadlocks in flexible manufacturing systems. The state space of a Petri net model can be divided into two disjoint parts: a live-zone and a dead-zone. Reachability graph analysis plays an important role in the modeling and control of Petri nets. Most existing studies have to fully enumerate the reachable markings of a Petri net to obtain the first-met bad markings (FBMs), which exacerbates the computational overheads. In this paper, a computationally efficient method to find dead markings in Petri nets is presented. We first introduce an algorithm to find dead markings by solving an integer linear programming problem. Then, the set of markings in the dead-zone is calculated, including the set of dead markings and the set of bad markings. Then we can find all the FBMs. By using a vector covering approach, the minimal covered set of FBMs is computed. The proposed approach can obtain the dead markings and FBMs by searching only a part of a reachability graph. Finally, examples are provided to demonstrate the proposed method.

Petri Net Model Based on Neural Network for Deadlock Control and Fault Detection and Treatment in Automated Manufacturing Systems

Previously, different deadlock control strategies for automated manufacturing systems (AMSs) based on Petri Nets with reliable resources have been proposed. However, in real-world applications, resources may be unreliable. Therefore, deadlock control strategies presented in previous research studies are not suitable for such applications. To address this issue, this paper proposes a novel three-step deadlock control strategy for fault detection and treatment of unreliable resource systems. In the first step, a controlled system (deadlock-free) is obtained using the “Maximum Number of Forbidding First met Bad Markings Problem 1” (MFFBMP1), which does not consider resource failures. Subsequently, all obtained monitors are merged into a single monitor based on a colored Petri net. The second step addresses deadlocks caused by resource failures in the Petri net model using a common recovery subnet based on colored Petri nets. The recovery subnet is applied to the system obtained in the first step to ensure that the system is reliable. The third step proposes a hybrid approach that combines neural networks with colored Petri nets obtained from the second step, for the detection and treatment of faults. The proposed approach possesses the advantages of modular integration of Petri nets and can also learn neurons and reduce knowledge, similar to neural networks. Therefore, this approach solves the deadlock problem in AMSs and also detects and treats failures. The proposed approach was tested using an example from literature.

Digital Image Processing Application on Shallots Quality Determination

Shallot is a horticultural vegetable commodity that has high economic value. North Sulawesi is one of the central production of shallots which has several onion varieties developed and marketed. Technology that can help determine the quality of shallots is needed to simplify the marketing process. This study aims to simulate a system for determining the quality of shallots based on their color and size. The shallot bulb image of several different varieties is input for this system to be able to provide good and bad shallot marks.

Supervisor Synthesis for FMS Based on Critical Activity Places

Solving states separation problems is an important technique to obtain liveness-enforcing and optimal or near-optimal supervisors for flexible manufacturing systems based on Petri nets. It first generates the model’s reachability graph and partitions it into a live zone (LZ) and a deadlock zone (DZ). Then, first-met bad markings (FBMs), which exist in DZ and are the very first entries from LZ to DZ, are forbidden by some designed place invariants (PIs) to prevent the system from entering DZ. This paper studies the reduction of the number of places to be considered in such PI designs. First, the concepts of critical transitions and critical activity places are defined, and a fast algorithm is provided to compute them. Then, the proofs of that only critical activity places need to be considered in such PI designs to forbid all FBMs and/or permit all legal markings in LZ are established.

Most permissive liveness-enforcing Petri net supervisors for discrete event systems via linear monitors

This paper proposes a deadlock prevention method to design a maximally permissive liveness-enforcing pure Petri net supervisor for a discrete event system, if such a supervisor exists; otherwise, it obtains the most permissive one in the sense that no other pure liveness-enforcing supervisors via linear monitors can be more permissive than it. This paper exploits an iterative method. At each iteration, a first-met bad marking (FBM) is singled out and an integer linear programming problem (ILPP) is configured. If a feasible solution can be found for the ILPP, then a place invariant (PI) is designed to prohibit the FBM from being reached while no legal marking is forbidden. If the ILPP has no solution, we collect all these FBMs that cannot be optimally controlled. For each of such FBMs, another ILPP is designed to find the least number of legal markings whose reachability conditions contradict the current considered FBM and enumerate all the optimal solutions of this ILPP. Based on it, we develop a 0–1 linear programming problem to find the maximal number of legal markings after removing all the contradictory legal markings. Then, the new sets of legal markings and FBMs are obtained, and we return to the iteration stage to redesign a PI to control each FBM if the ILPP has a feasible solution. Repeat the above process until no FBM can be reached. Finally, a most permissive pure liveness-enforcing supervisor via linear monitors is derived. Two Petri net models are used to illustrate the proposed method.

Time-Varying Automated Manufacturing Systems and Their Invariant-Based Control: A Petri Net Approach

As an important branch of production facilities, automated manufacturing systems are a promising perspective of modern factories which become increasingly complex and flexible. From the perspective of development, time variable is a significant concern. In this paper, we propose a class of time-varying systems, Tv-S4R. After involving a global time information loop, it can represent realistic system whose manufacturing process varies with time variables. Event-based control is introduced for serving two important purposes. First, it exerts time-varying specifications on the system, i.e., different processes are executed at different time stages. Second, it prevents the system from reaching any first-met bad marking which will eventually result in deadlocks. We will show that the event-based control can enhance our specifications' expressivity capability compared to their state-based counterparts in terms of generalized mutual exclusion constraints. At last, supervisors are simplified according to the identification of dependence and independence of inequalities. An experimental study illustrates the application of Tv-S4R and the effectiveness of event-based control method.