Efficient Patrolling Research Articles

Patrolling AI Systems in Video Games

Artificial Intelligence is a common element in digital video games and it is one of the most essential component in modern games. Modern games are populated with Non-Player Characters (AI Characters) that performs different activities. Realism is dominating in games and AI behavio rs are expected to be more realistic in games. Games that has poor unrealistic AI elements are facing heavy criticism from the player bases. Further, modern games are highly dynamic. Classical games had static environment with less or no changes in it. Such environments made implementation of AI easy and simple. In modern games, Progressive terrain generation and other such content generation methods increases the complexities of building an efficient AI for games that has many changes in real time. One of the most common AI in games is Patrolling AI especially in Shooter and Adventure Games. Patroling AI involves path finding and obstacle attack or defense. RRT algorithm and its variants are highly successful Probabilistic Determination AI that produced effective results in real time robotic movement. In order to build efficient Patrolling AI for games, a real time RRT* variant called RT-RRT* algorithm was employed. The algorithm is flexible enough to add various behaviors in addition to path finding which makes it more suitable for games. The algorithm takes samples from the environment and construct the efficient path. Also the algorithm inspect the environment in run time to ensure that no moving obstacle blocks the path. In such case, it rewires and create a new path. In order to manage the dynamic obstacles, a Real Time Obstacle Handling Algorithm was designed and employed in a dynamic game environment. The algorithms inputs the obstacles types and parameters. On identifying the obstacle approaching the AI in terrain, it tells the agent to perform the needed actions. The simulations was carried out using Unity Game Engine. The model proposed helped to create efficient patrolling AI that handle two major aspects of patrolling which is Path finding and Obstacle handling. The model will be highly suitable for dynamic game environments with lots of uncertainty and emergence.

A Monte Carlo Tree Search approach to finding efficient patrolling schemes on graphs

In this paper, we propose an evader-defender type of game for modeling multi-step patrolling scenarios on a graph. The game utilizes a specifically designed graph-based setting which captures spatial arrangements of the protected area, for instance industrial premises or warehouses, wherein certain valuable assets are stored. The game is played by two sides: the evader who attempts to steal or destroy the assets and the defender whose aim is to intercept the evader and prevent him/her from accomplishing his/her goal.Real-life specificity of the proposed game assumes information asymmetry between the two sides as the evader can usually observe defender’s patrolling schedules prior to making decision of an attack. For this reason, we employ the Stackelberg Game principles to model our game and consequently focus on approximation of Stackelberg Equilibrium during the solution process. To this end we propose a novel approach, called Mixed-UCT, which relies on Upper Confidence Bound applied to Trees algorithm – a variant of Monte Carlo Tree Search.The efficacy of the proposed solution method is experimentally evaluated on randomly generated games played in warehouse-like, industrial environment. The results show that Mixed-UCT is efficient and scales very well for multi-step games with reasonable number of steps, leading to optimal or close-to-optimal strategies.

Designing game-theoretic security strategies for large public events

High-profile, large-scale public events may be attractive targets for terrorist attacks. The security challenge for such events is exacerbated by their dynamic nature: the impact of an attack on different `targets, such as studio entrances, changes over time. In addition, the defender can relocate security resources among potential attack targets at any time, while the attacker may act at any time during the event. This study focuses on developing efficient patrolling algorithms for such dynamic domains, with continuous strategy spaces for both the defender and attacker. We propose SCOUT-A, which makes assumptions regarding relocation costs, exploits payoff representation, and computes optimal solutions efficiently. We furthermore propose SCOUT-C, to compute the exact optimal defender strategy for general cases despite the continuous strategy spaces. The experimental results demonstrate that our algorithms significantly outperform existing strategies.

Path Construction and Visit Scheduling for Targets by Using Data Mules

In this paper, the target patrolling problem was considered, in which a set of mobile data collectors, known as data mules (DMs), must efficiently patrol a given set of targets. Because the time interval (or visiting interval) between consecutive visits to each target reflects the degree to which that target is monitored, the goal of this paper was to balance the visiting interval of each target. This paper first presents the basic target points patrolling algorithm, which enables an efficient patrolling route to be constructed for numerous DMs, such that the visiting intervals of all target points are stable. For scenarios containing weighted target points, a weighted target points patrolling (W-TPP) algorithm is presented, which ensures that targets with higher weights have higher data collection frequencies. The energy constraint of each DM was also considered, and this paper presents a W-TPP with recharge (RW-TPP) algorithm, which treats the energy recharge station as a weighted target and arranges for DMs to visit the recharge station before running out of energy. The performance results demonstrated that the proposed algorithms outperformed existing approaches in average visiting frequency, DM movement distance, average quality of monitoring satisfaction rate, and efficiency index.

Game-Theoretic Resource Allocation for Protecting Large Public Events

High profile large scale public events are attractive targets for terrorist attacks. The recent Boston Marathon bombings on April 15, 2013 have further emphasized the importance of protecting public events. The security challenge is exacerbated by the dynamic nature of such events: e.g., the impact of an attack at different locations changes over time as the Boston marathon participants and spectators move along the race track. In addition, the defender can relocate security resources among potential attack targets at any time and the attacker may act at any time during the event. This paper focuses on developing efficient patrolling algorithms for such dynamic domains with continuous strategy spaces for both the defender and the attacker. We aim at computing optimal pure defender strategies, since an attacker does not have an opportunity to learn and respond to mixed strategies due to the relative infrequency of such events. We propose SCOUT-A, which makes assumptions on relocation cost, exploits payoff representation and computes optimal solutions efficiently. We also propose SCOUT-C to compute the exact optimal defender strategy for general cases despite the continuous strategy spaces. SCOUT-C computes the optimal defender strategy by constructing an equivalent game with discrete defender strategy space, then solving the constructed game. Experimental results show that both SCOUT-A and SCOUT-C significantly outperform other existing strategies.

Assessment of Present Status and Future Needs of Four Coral Reef Sites Along the Gulf of Aqaba, Egypt

The present status and future needs of four coral reef sites (Taba, Nuweiba , Dahab and Sharm El-Sheikh) along the Gulf of Aqaba, Egypt were evaluated. A total of 60 quadrats, distributed at different depths or different patches were surveyed at each site during the year 2007. Three mooring buoys were reported only in Ras Umm Seid but nothing was found in other sites, however excessive boating and diving pressure were recorded only in Ras Umm Seid. Highest amount of garbage was recorded in Nuweiba, patrolling efficiency was best in Taba but no patrolling activities were re- corded in other sites. Ras Umm Seid (Sharm El-Sheikh) had the highest amount of dead corals (13%) due to increased boating and diving pressure compared to other sites, however Dahab had the lowest amount of dead corals (4%) due to the rough conditions (strong wind and waves) causing difficulties in accessing that site. Nuweiba and Taba had high percent cover of sands (10% and 11%, respectively) playing a key role in the considerable amount of dead corals in both sites. Lowest % new coral recruits in Taba (0.5%) was associated with the soft sandy bottom, the opposite was true in Sharm El Sheikh due to the rocky bottom. Future needs of the studied sites include decreasing the number of divers to the diver car- rying capacity (DCC), repair of existing buoys and incorporation of 5 more buoys in Ras Umm Seid. Other sites have no future needs in these regards as they are far beyond the DCC. Nuweiba needs first of all to be cleaned, then being pro- tected for giving the chance of recovery. Except for Taba which has efficient patrolling, the other 3 sites need efficient ter- restrial and marine patrolling as well as enforcement of EEAA regulations. However reef access points which were absent in all sites need to be established to minimize reef damage on accessing deeper water. Also, the environmental awareness field signs which were absent in all sites need to be established and managed. Taba is recommended as a protected area as it has the food for threatened species beside being useful as a nesting site. Ras Umm Seid is recommended to have a estab- lished artificial reef to draw the attention of divers and snorklers from the natural reefs and prepare artificial shelters for fishes thus promoting the fish resources.

Uracil DNA glycosylase uses DNA hopping and short-range sliding to trap extrahelical uracils

The astonishingly efficient location and excision of damaged DNA bases by DNA repair glycosylases is an especially intriguing problem in biology. One example is the enzyme uracil DNA glycosylase (UNG), which captures and excises rare extrahelical uracil bases that have emerged from the DNA base stack by spontaneous base pair breathing motions. Here, we explore the efficiency and mechanism by which UNG executes intramolecular transfer and excision of two uracil sites embedded on the same or opposite DNA strands at increasing site spacings. The efficiency of intramolecular site transfer decreased from 41 to 0% as the base pair spacing between uracil sites on the same DNA strand increased from 20 to 800 bp. The mechanism of transfer is dominated by DNA hopping between landing sites of approximately 10 bp size, over which rapid 1D scanning likely occurs. Consistent with DNA hopping, site transfer at 20- and 56-bp spacings was unaffected by whether the uracils were placed on the same or opposite strands. Thus, UNG uses hopping and 3D diffusion through bulk solution as the principal pathways for efficient patrolling of long genomic DNA sequences for damage. Short-range sliding over the range of a helical turn allows for redundant inspection of very local DNA sequences and trapping of spontaneously emerging extrahelical uracils.

Effects of sex and strain on exploratory locomotion and development of nonreinforced maze patrolling

Continuous recording of locomotion in an enclosed maze with no reinforcement other than that intrinsic to ambulation through the maze provided evidence for a dissociation between the efficiency of patrolling the entire maze and locomotor activity. Patrolling efficiency improved with repeated exposure to a single maze or to two similar maze configurations but not with daily presentation of dissimilar mazes. There were only small strain and sex differences in the development of efficient patrolling, whereas locomotor activity was considerably higher in female Roman high-avoidance (RHA) rats than in female Roman low-avoidance rats and higher in RHA female rats than in RHA male rats.