Abstract: In an embodiment an apparatus includes a processor configured to generate a feature extraction module using a dataset in which an attribute for each object is defined, receive an image obtained by a camera, extract an attribute of an object of interest from the image using the learned feature extraction module, identify an object re-identification candidate group based on the extracted attribute of the object of interest and re-identify the object of interest based on the identified object re-identification candidate group.

Abstract: Novel calix[4]arene dibenzo crown ethers useful to selectively extract cesium are represented by the formula: wherein R is a C.sub.1 -C.sub.10 normal alkyl, a phenyl or a methoxyphenyl, R' is hydrogen, p-tert-butyl or a C.sub.1 -C.sub.10 normal alkyl, R" is a C.sub.1 -C.sub.10 normal alkyl, and n is an integer of 0-2. The novel compound is prepared at high yields by introduction of benzene rings into the crown ether ring of calix[4]arene crown-6-ether. The calix[4]arene dibenzo crown ethers are superior in selective absorptivity for cesium ions by virtue of their 1,3-alternate conformational structure and thus, can be used as selective extractants able to separate cesium ions at a high efficiency.