Theoretical network analysis of a network constructed of "Interconnectable Star Couplers" whose all diagonal elements of transmission matrix are zero is investigated. Under certain connection rules, Interconnectable Star Coupler can be connected each other without oscillation and ghost formation. The rules are: (1) Network should not contain any loop. (2)Only single port pair should be connected between neighbor star couplers. (3)Network shold not contain any usual star coulpler. "Coupled Star Network", which is constructed under the connection rules, is able to form Cascade Star topology, Stratified Star topology and their mixed topology. It is shown that the Coupled Star Network is equivalent to a large Interconnectable Star Coupler so that bidirectional communication, which can add confidentiality to the broadcasting bus and doubles communication capacity, is available. A new configuration of Coupled Star Network using passive Interconnectable Star Couplers and optical amplifiers is proposed. This network has two separated bidirectional communication channel which can be applied for so-called Multimedia LAN. As a result of comparison between Cascade Star topology and Stratifide Star topology, it is shown that the latter topology is superior to former topology, from the view point of signal degeneration and maximum round trip delay time. Cascade Star topology, however, is superior to Stratified Star topology from the angle of total fiber length. Accordingly, optimized network topology is thought to be mixed topology of these.

Physical optics (PO) have been extensively used in radiation pattern analysis of offset parabola. Physical Theory of Diffraction (PTD) proposed later has better accuracy. This paper presents an analytical/numerical comparative study of these methods to demonstrate the limitations of PO. PO envelope errors in co-polar patterns are expressed as functions of antenna parameters. Serious PO errors in cross polarization prediction are pointed out for antennas with cross-polar suppressing feeds polarized in the plane of asymmetry.

One performance limitation of the "Leaky Bucket algorithm" for usage parameter control and traffic management in Asynchronous Transfer Mode (ATM) networks is analyzed. Simulation results show that the conventional statistical bandwidth allocation method, which uses the most bursty pattern permitted by the Leaky Bucket algorithm, can not guarantee the QOS of established Virtual Channels/Paths (VC/VP). As a result, the VC/VP bandwidth allocation method based on the Leaky Bucket algorithm is proven to be unsatisfactory.

The behavior of TM-wave scattering from a dielectric-loaded semicircular trough in a conducting half-space is investigated. The dielectric loading is made of a circular cylinder which lies in a semi-circular trough in the perfectly conducting plane. The formulation is numerically evaluated to investigate the scattered field pattern for various dielectric loading conditions. It is found that the scattering patterns exhibit the resonant behavior due to both of the concave surface contour and the dielectric loading.