Academic literature on the topic 'Defensive game systems'

Communication-based train controls (CBTC) systems play a major role in urban rail transportation. As CBTC systems are no longer isolated from the outside world but use other networks to increase efficiency and improve productivity, they are exposed to huge cyber threats. This paper proposes a generalized stochastic Petri net (GSPN) model to capture dynamic interaction between the attacker and the defender to evaluate the security of CBTC systems. Depending on the characteristics of the system and attack–defense methods, we divided our model into two phases: penetration and disruption. In each phase, we provided effective means of attack and corresponding defensive measures, and the system state was determined correspondingly. Additionally, a semiphysical simulation platform and game model were proposed to assist the GSPN model parameterization. With the steady-state probability of the system output from the model, we propose several indicators for assessing system security. Finally, we compared the security of the system with single defensive measures and multiple defensive measures. Our evaluations indicated the significance of the defensive measures and the seriousness of the system security situation.

The aims of the current study were (a) to analyze the differences in game performances of sitting volleyball athletes representing the different types of disabilities and (b) to assess whether the seated position vertical reach is one of the crucial factors in the game performance level of sitting volleyball athletes. One hundred male athletes from various national teams participating in the European Championships in Sitting Volleyball (2009) took part in this study. The athletes were categorized according to type of disability and the results of the vertical reach in a seated position. Thirtysix games were analyzed using the Game Performance Sheet for Sitting Volleyball. Twenty-three game performance parameters were studied. In addition, the sum and effectiveness of attacks, blocks, block services, services, ball receiving, and defensive actions were calculated. The main results indicated significant differences between athletes with minimal disability and athletes with single amputations from above the knee in the level of defensive performances and the summation of defensive actions. There was also a significant difference between athletes in relation to their vertical reach during activity and attacking actions, blocks, and ball receiving. In addition, there were strong relationships between the players’ vertical reach scores and their activity and effectiveness in sitting volleyball. In conclusion, the accuracy of the World Organization Volleyball for Disabled classification systems for sitting volleyball players was confirmed. There is a strong relationship between players’ vertical reach and their effectiveness in sitting volleyball.

The use of machine learning to identify and classify offensive and defensive strategies in team sports through spatio-temporal tracking data has received significant interest recently in the literature and the global sport industry. This paper focuses on data-driven defensive strategy learning in basketball. Most research to date on basketball strategy learning has focused on offensive effectiveness and is based on the interaction between the on-ball player and principle on-ball defender, thereby ignoring the contribution of the remaining players. Furthermore, most sports analytical systems that provide play-by-play data is heavily biased towards offensive metrics such as passes, dribbles, and shots. The aim of the current study was to use machine learning to classify the different defensive strategies basketball players adopt when deviating from their initial defensive action. An analytical model was developed to recognise the one-on-one (matched) relationships of the players, which is utilised to automatically identify any change of defensive strategy. A classification model is developed based on a player and ball tracking dataset from National Basketball Association (NBA) game play to classify the adopted defensive strategy against pick-and-roll play. The methodology described is the first to analyse the defensive strategy of all in-game players (both on-ball players and off-ball players). The cross-validation results indicate that the proposed technique for automatic defensive strategy identification can achieve up to 69% accuracy of classification. Machine learning techniques, such as the one adopted here, have the potential to enable a deeper understanding of player decision making and defensive game strategies in basketball and other sports, by leveraging the player and ball tracking data.

Abstract In many sports, such as soccer, a coach has to decide whether to adopt an “offensive” or a “defensive” approach to a match. This strategic decision depends on the strengths and weaknesses of his team with respect to the opponent, but also on the strategy chosen by the opponent’s coach. The fact that a draw also results in a point, which may be important for the ranking, further complicates this decision, as the coach must assess whether it is better to adopt a defensive team formation in order to obtain a draw, or to aim for victory despite the increased risk of defeat. We study this topic by means of a game-theoretical approach, and we develop an algorithm which allows to compute the optimal strategy. The algorithm tests the stability of the outcome with respect to uncertainty in the estimated win probabilities. Furthermore, our approach can handle in-game events, which may provoke changes in optimal strategy. Finally, our model also allows us to assess the effect of various point systems on the willingness of teams to opt for attacking play. Our method is applied to a case study, based on the match Italy – Costa Rica (World Cup 2014).

Access blocks throughout the entire healthcare system and overcrowding issues are pervasive in many emergency departments where the coordination and strategic management of resources could be supported by serious games and simulations approaches. However, existing studies have not addressed the reciprocal relation between patient inflow and working systems in serious games design in order to reflect the logistical features of an emergency department and to facilitate the players improve the work performance of the system. To address the issue, this paper presents a serious game based on a multi-method simulation approach of complex healthcare processes as well as the game mechanics selected to promote understanding the logistical features of an ED, which points to the next level of conducting simulations or gaming aimed for training decision making skills in operative environments. Results of the experiment confirmed that the serious game encouraged participants to proactively manage the human resources of the emergency department. Certain managerial recommendations can be made: a patient flow multiplier of 120% could lead to a significant erosion of the system’s defensive ability; however, proactive anticipation from management is the key for making an emergency organization more resilient.

In this study, we explored how manipulating floaters’ positions in small-sided futsal games (SSGs) promote changes in the informational constraints that support decision-making (DM) for passing, dribbling and shooting tactics. We made changes in four experimental 3 vs 3 small-sided game conditions with 30 male futsal players (U19 age category): (a) Floaters Off (FO), (b) Final Line Floaters (FLF), (c) Lateral Floaters own field sideline (LFofsl) and (d) Lateral Floaters full field sideline (LFffsl). We assessed players’ activity with WIMU PRO™ software during the SSGs, using the Game Performance Evaluation Tool (GPET) to analyze a total of 1,635 decisions. DM for dribbling was generally based on the interpersonal distance between the ball carrier and direct opponent, considering the defensive team length and the offensive team area. Shooting decisions were constrained, by certain attacking-defending teams’ spatial-temporal relations with regard to playing space and team balance as affected by manipulating floaters’ positions. The coaches’ decisions to change the floaters’ positions during SSGs may change informational variables sustaining the dribbling decision, but no changes in SSG variables affected passing DM.

Sistemas tácticos y resultados de competición del Mundial de Fútbol Asociación de Rusia 2018Tactical systems and match results from FIFA Worldcup Rusia 2018Julio Cesar Guedea Delgado, Raúl Josué Nájera Longoria, Oscar Núñez Enríquez, Ramón Candía Luján, Gabriel Gastélum CuadrasUniversidad Autónoma de Chihuahua (México) Resumen. Los sistemas tácticos dentro del fútbol soccer son elementales tanto a la ofensiva como a la defensiva. El presente estudio consiste en el analizar los sistemas tácticos y resultados de juego de Mundial de Rusia 2018. Se analizaron los 64 partidos, cuyos datos se extrajeron de la Web oficial de la Federación Internacional de Fútbol Asociación (FIFA, www.fifa.com) y registros que se obtuvieron del programa de Sky SPORTS® del canal 1535, los datos se confirmaron mediante el Sky SPORTS® que ofrece una toma táctica aérea en el canal 1536. Los resultados más sobresalientes son el sistema más utilizado el 1-4-2-3-1, donde los dos equipos del 1ro Francia y 2do lugar Croacia lo utilizaron con mayor frecuencia, así mismo el 1-3-5-2 y 1-3-4-3 que son más ofensivos, en los equipos del 3ro lugar Bélgica y 4to lugar Inglaterra. Estos sistemas en ocasiones a la defensiva cambian, dependiendo del rival y las circunstancias, así como la táctica del entrenador. Hoy en día, los sistemas de juego y las metodologías de entrenamiento marcan una pauta específica para los entrenadores, buscando futbolistas que dominen los aspectos técnico-tácticos, que entiendan el sistema y la filosofía de juego que plantea el entrenador y que defiendan y ataquen con la misma intensidad independientemente de la posición que asuman.Abstract. Tactical systems within football (soccer) are either used in offense and defense. This study aims at analyzing match results and tactical systems during the Russia 2018 World Cup. All 64 matches were analyzed, data being extracted from the official website of the International Federation (FIFA, www.fifa.com), whereas records from the Sky SPORTS® channel 1535. Data was confirmed with Sky SPORTS® since it offers a sky view in their channel 1536. The most used lineup system was 1-4-2-3-1, with teams such as France (1st) and Croatia (2nd) using it more frequently, as well the lineup 1-3-5-2 and 1-3-4-3, which are more offensive, used by teams such as Belguim (3rd) and England (4th). These lineup systems, together with the coaching tactics, occasionally changed defensive wise, upon rival and circumstances. Currently, game systems and training methodologies set the pace for coaches, who look for football players who dominate technical-tactics aspects, understand the systems, their game philosophy, and being tough offensive and defensive players regardless of their field position.

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n1p62 The aim of this study was to compare the collective tactical behavior between numerically balanced and unbalanced small-sided soccer games. Eighteen male soccer players (mean age 16.4 years) participated in the study. Polar coordinate analysis was performed using positional data obtained with a 15-Hz GPS device. Collective variables including length, width, centroid distance (average point between teammates), and length per width ratio (LPWratio) were collected. Data were analyzed using Friedman’s test. The results showed greater length and width values in 4vs.3 games, while a higher LPWratiowas observed in 3vs.3+2 games compared to the other configurations. In games with an additional player (4vs.3), ball circulation and the increase in effective game space were alternatives to overcome the more concentrated defensive systems near the goal. On the other hand, 3vs.3+2 games allowed more actions in the length axis and a fast reach of the opponent’s goal.

Purpose:To characterize the physical and physiological responses during different basketball practice drills and games.Methods:Male basketball players (n = 11; 19.1 ± 2.1 y, 1.91 ± 0.09 m, 87.9 ± 15.1 kg; mean ± SD) completed offensive and defensive practice drills, half court 5on5 scrimmage play, and competitive games. Heart rate, VO2 and triaxial accelerometer data (physical demand) were normalized for individual participation time. Data were log-transformed and differences between drills and games standardized for interpretation of magnitudes and reported with the effect size (ES) statistic.Results:There was no substantial difference in the physical or physiological variables between offensive and defensive drills; physical load (9.5%; 90% confidence limits ±45); mean heart rate (-2.4%; ±4.2); peak heart rate (-0.9%; ±3.4); and VO2 (–5.7%; ±9.1). Physical load was moderately greater in game play compared with a 5on5 scrimmage (85.2%; ±40.5); with a higher mean heart rate (12.4%; ±5.4). The oxygen demand for live play was substantially larger than 5on5 (30.6%; ±15.6).Conclusions:Defensive and offensive drills during basketball practice have similar physiological responses and physical demand. Live play is substantially more demanding than a 5on5 scrimmage in both physical and physiological attributes. Accelerometers and predicted oxygen cost from heart rate monitoring systems are useful for differentiating the practice and competition demands of basketball.

PurposeThe purpose of this paper is to focus on resource allocation and information disclosure policy for defending multiple targets against intentional attacks. The intentional attacks, like terrorism events, probably cause great losses and fatalities. Attackers and defenders usually make decisions based on incomplete information. Adaptive attacking and defending strategies are considered, to study how both sides make more effective decisions according to previous fights.Design/methodology/approachA stochastic game‐theoretic approach is proposed for modeling attacker‐defender conflicts. Attackers and defenders are supposed both to be strategic decision makers and partially aware of adversary's information. Adaptive strategies are compared with different inflexible strategies in a fortification‐patrol problem, where the fortification affects the security vulnerability of targets and the patrol indicates the defensive signal.FindingsThe result shows that the intentional risk would be elevated by adaptive attack strategies. An inflexible defending strategy probably fails when facing uncertainties of adversary. It is shown that the optimal response of defenders is to adjust defending strategies by learning from previous games and assessing behaviors of adversaries to minimize the expected loss.Originality/valueThis paper explores how adaptive strategies affect attacker‐defender conflicts. The key issue is defense allocation and information disclosure policy for mitigation of intentional threats. Attackers and defenders can adjust their strategies by learning from previous fights, and the strategic adjustment of both sides may be asynchronous.