We study a recently introduced \textit{unconscious} mobile robot model, where each robot is associated with a \textit{color}, which is visible to other robots but not to itself. The robots are autonomous, anonymous, oblivious and silent, operating in the Euclidean plane under the conventional \textit{Look-Compute-Move} cycle. A primary task in this model is the \textit{separation problem}, where unconscious robots sharing the same color must separate from others, forming recognizable geometric shapes such as circles, points, or lines. All prior works model the robots as \textit{transparent}, enabling each to know the positions and colors of all other robots. In contrast, we model the robots as \textit{opaque}, where a robot can obstruct the visibility of two other robots, if it lies on the line segment between them. Under this obstructed visibility, we consider a variant of the separation problem in which robots, starting from any arbitrary initial configuration, are required to separate into concentric semicircles. We present a collision-free algorithm that solves the separation problem under a semi-synchronous scheduler in $O(n)$ epochs, where $n$ is the number of robots. The robots agree on one coordinate axis but have no knowledge of $n$.

翻译：我们研究一种近期提出的\textit{无意识}移动机器人模型，其中每个机器人与一种\textit{颜色}相关联，该颜色对其他机器人可见但对自身不可见。机器人具有自主性、匿名性、无记忆性且无通信能力，在欧几里得平面中按照经典的\textit{观察-计算-移动}周期运行。该模型中的一个核心任务是\textit{分离问题}，即具有相同颜色的无意识机器人必须与其他机器人分离，形成可识别的几何形状（如圆形、点或直线）。现有研究均将机器人建模为\textit{透明}个体，使得每个机器人能获知所有其他机器人的位置和颜色。与此不同，我们将机器人建模为\textit{不透明}个体，当某个机器人位于另外两个机器人的连线线段上时，它会阻碍这两个机器人之间的相互可见性。在这种视线受阻模型下，我们研究分离问题的一个变体：要求机器人从任意初始配置出发，最终分离成同心半圆形排列。我们提出了一种无碰撞算法，该算法在半同步调度器下以$O(n)$个周期解决分离问题，其中$n$为机器人数量。所有机器人能就一个坐标轴方向达成共识，但对$n$的值并无先验知识。