Disclosed is a thermoelectric module, including: a first substrate; a plurality of thermoelectric elements arranged on a first surface of the first substrate; and a temperature detector disposed on the first surface or a second surface of the first substrate via a thermal transfer member. At least two cores of the plurality of cores have different associated mean propagation constants at a reference wavelength. A first virtual server in the virtual network is chosen randomly, and a path generated from the first virtual server to a root virtual server. Each service request obtained from an application program may be translated into multiple actions performed using various specific protocols andor interfaces provided by either the management plane, the control plane, or both the management and control planes. The memory device has a plurality of power modes, including a first mode in which the clock receiver circuit, first interface, and data interface are turned off; a second mode in which the clock receiver is turned on and the first interface and data interface are turned off; and a third mode in which the clock receiver and first interface are turned on. Each class definition may also include an optimum setting for each parameter.