We present two new versions of the chromatic art gallery problem that can improve upper bound of the required colors pretty well. In our version, we employ restricted angle guards so that these modern guards can visit α-degree of their surroundings. If α is between 0 and 180 degree, we demonstrate that the strong chromatic guarding number is constant. Then we use orthogonal 90-degree guards for...

In polyandrous species, males seek to maximize their reproductive output by monopolizing their mate. Often the male transfers substances to the female that suppress her sexual receptivity or antagonize the behavior of competing males; both are usually transferred in seminal fluids and represent forms of chemical mate guarding. In moths, more long-range female sex pheromones have been identified...

We describe a polynomial time O(k log log OPTk(P ))approximation algorithm for the k-guarding problem of finding a minimum number, OPTk(P ), of vertex guards of an n-vertex simple polygon P so that for every point p ∈ P , the number of guards that see p is at least the minimum of k and the number of vertices that see p. Our approach finds O ( k ε log log 1 ε ) size (k, ε)-nets for instances of ...

Precopulatory guarding in Crustacea is usually analyzed as a male decision problem. We suggest an alternative possibility that precopula is established as a result of intersexual conflict over precopula duration. Such a conflict can be expected when the male optimum for precopula duration exceeds the female optimum. As a result, males should start precopulatory attempts earlier, while females s...

For every hierarchical system of equations S over some complete and distributive lattice we construct an equivalent system with the same set of variables which additionally is guarded. The price to be paid is that the resulting right-hand sides may grow exponentially. We therefore present methods how the exponential blow-up can be avoided. Especially, the loop structure of the variable dependen...

We study the Art Gallery Problem for face guards in polyhedral environments. The problem can be informally stated as: how many (not necessarily convex) windows should we place on the external walls of a dark building, in order to completely illuminate it? We consider both closed and open face guards (i.e., faces with or without their boundary), and we give some upper and lower bounds on the min...

In this paper we evaluate the effects of guarded (or conditional, or predicated) execution on the performance of an instruction level parallel processor employing dynamic branch prediction. First, we assess the utility of guarded execution, both qualitatively and quantitatively, using a variety of application programs. Our assessment shows that guarded execution significantly increases the oppo...

Abstract This paper traces the conception of “guarding One” ( shou yi 守一 ), an equivalent to “one-practice samādhi ” from East Mountain Teaching dong shan fa men 東山法門 ) in early Chan Buddhism, back Zhuangzi 《莊子》 . “Guarding and “nurturing shen yang 養神 appear frequently context Daoist spiritual training for longevity. In medieval Chinese with influence discourse karma theory India, concept 神 gen...

In species where females mate with multiple males, the sperm from these males must compete to fertilise available ova. Sexual selection from sperm competition is expected to favor opposing adaptations in males that function either in the avoidance of sperm competition (by guarding females from rival males) or in the engagement in sperm competition (by increased expenditure on the ejaculate). Th...

Securing a potential mate is one of the most important processes in sexual reproduction of animals. Intertidal copepods of the genus Tigriopus show mate-guarding behavior where a male captures a female and continues to clasp her for up to two weeks prior to copulation. Although these copepods form a mate-guarding pair between a male and a female with high accuracy, interactions between the sexe...