A high power and low distortion 1.31 μm AlGaInAs/InP multiquantum well distributed feedback laser diode (MQW DFB LD) with RWG structure has been developed by MOCVD technique. The fiber output power of butterfly packa...A high power and low distortion 1.31 μm AlGaInAs/InP multiquantum well distributed feedback laser diode (MQW DFB LD) with RWG structure has been developed by MOCVD technique. The fiber output power of butterfly packaged module with optic isolator P f is more than 10 mW, threshold current is in the range of (13～20) mA, slope efficiency, E s>0.30 W/A and side mode suppression ratio, R S,M,S >35 dB. The composite second order, O C,S <-61 dBc and composite triple beat, B C,T <-65 dBc are obtained by test frequencies of (45～550) MHz with 60 PAL channels. In the test conditions the carrier to noise ratio, R C,N >51 dB.展开更多
The problem of geometric non-linearity simulation for spacial cable system was solved by introducing the truss element based on corotational coordinate (CR) system, cable structure materials and node coordinates and a...The problem of geometric non-linearity simulation for spacial cable system was solved by introducing the truss element based on corotational coordinate (CR) system, cable structure materials and node coordinates and automatic refreshing algorithms for element internal force. And the shape-finding problem for maneuvering profile was solved with the Newton-Raphson based on energy convergence criteria with search function. This has avoided the regular truss element assumption extensively used in traditional methods and catenary elements which have difficulties in practical application because of the complicated formulas. The use of CR formulation has taken into account the stiffness outside the cable plane via a geometric stiffness matrix, realizing the 3D space analysis of a cable bridge and improving the efficiency and precision for the space geometric non-linearity analysis and cable structure, and enabling more precised simulation of geometric form finding and internal force of the large span suspension bridge main cable under construction.展开更多
This paper aims to analyze a case of a telecom operator, Korea Telecom （KT）＇s hybrid business model---Olleh TV Skylife （OTS）. This case is KT＇s new hybrid network and set-top-box （STB） which combines Internet ...This paper aims to analyze a case of a telecom operator, Korea Telecom （KT）＇s hybrid business model---Olleh TV Skylife （OTS）. This case is KT＇s new hybrid network and set-top-box （STB） which combines Internet Protocol TV （IPTV） with Direct-To-Home （DTH） satellite reception and business. It serves now as a guideline to better understanding hybrid consumer behavior and their needs. This paper shows how KT＇s OTS has been formulated as a new business model, how it has changed the market structure, and how it has experienced a successful market performance with new business idea and innovative technology. Before analyzing this case, it firstly discusses about the technological situation and the industrial organization （IO） theory. After this, it shows the previous service offerings of cable TV, satellite TV, and IPTV, before launching OTS and shows that the mixed service portfolio of satellite TV and IPTV is the perfect service combination to beat the cable TV in terms of hybrid consumer needs. After explanation about OTS, this paper verifies whether this hybrid business model really changes market and generates a good market performance and operating synergy with KT＇s other businesses of content, network, and marketing. In conclusion, this paper expects future growth potential of OTS and KT Skylife in terms of subscription fee, home shopping, and advertising sales based on the total subscriber base.展开更多
A numerical method is developed to investigate the dynamic response of cable-seabed interaction in this paper. The motion of cable is described by the Lumped Parameter Method, while the seabed, unlike the prevailing s...A numerical method is developed to investigate the dynamic response of cable-seabed interaction in this paper. The motion of cable is described by the Lumped Parameter Method, while the seabed, unlike the prevailing simplified model of elastic foundation, is modeled as an irregular continuous rigid surface with rebound and friction existing, and the forces exerted by the seabed consist of normal counterforce and isotropic tangential Coulomb friction resistance. To describe the detailed dynamic response, two coefficients are introduced by analogy with the theory of rigid body collision with friction. The cable-seabed kinematic and dynamic contact conditions are formulated subsequently, and are used to incorporate the seabed effect into the cable dynamics to produce a set of ordinary differential governing equations. In this paper, we employ 4th order Runge-Kutta method to solve these equations. Several simulation cases are presented to illustrate the seabed effect. The results show that friction and impact have a prominent influence on the statics and dynamics of the cable.展开更多
文摘A high power and low distortion 1.31 μm AlGaInAs/InP multiquantum well distributed feedback laser diode (MQW DFB LD) with RWG structure has been developed by MOCVD technique. The fiber output power of butterfly packaged module with optic isolator P f is more than 10 mW, threshold current is in the range of (13～20) mA, slope efficiency, E s>0.30 W/A and side mode suppression ratio, R S,M,S >35 dB. The composite second order, O C,S <-61 dBc and composite triple beat, B C,T <-65 dBc are obtained by test frequencies of (45～550) MHz with 60 PAL channels. In the test conditions the carrier to noise ratio, R C,N >51 dB.
基金National Science and Technology Support Program of China(No.2009BAG15B01)Key Programs for Science and Technology Development of Chinese Transportation Industry(No.2008-353-332-190)
文摘The problem of geometric non-linearity simulation for spacial cable system was solved by introducing the truss element based on corotational coordinate (CR) system, cable structure materials and node coordinates and automatic refreshing algorithms for element internal force. And the shape-finding problem for maneuvering profile was solved with the Newton-Raphson based on energy convergence criteria with search function. This has avoided the regular truss element assumption extensively used in traditional methods and catenary elements which have difficulties in practical application because of the complicated formulas. The use of CR formulation has taken into account the stiffness outside the cable plane via a geometric stiffness matrix, realizing the 3D space analysis of a cable bridge and improving the efficiency and precision for the space geometric non-linearity analysis and cable structure, and enabling more precised simulation of geometric form finding and internal force of the large span suspension bridge main cable under construction.
文摘This paper aims to analyze a case of a telecom operator, Korea Telecom （KT）＇s hybrid business model---Olleh TV Skylife （OTS）. This case is KT＇s new hybrid network and set-top-box （STB） which combines Internet Protocol TV （IPTV） with Direct-To-Home （DTH） satellite reception and business. It serves now as a guideline to better understanding hybrid consumer behavior and their needs. This paper shows how KT＇s OTS has been formulated as a new business model, how it has changed the market structure, and how it has experienced a successful market performance with new business idea and innovative technology. Before analyzing this case, it firstly discusses about the technological situation and the industrial organization （IO） theory. After this, it shows the previous service offerings of cable TV, satellite TV, and IPTV, before launching OTS and shows that the mixed service portfolio of satellite TV and IPTV is the perfect service combination to beat the cable TV in terms of hybrid consumer needs. After explanation about OTS, this paper verifies whether this hybrid business model really changes market and generates a good market performance and operating synergy with KT＇s other businesses of content, network, and marketing. In conclusion, this paper expects future growth potential of OTS and KT Skylife in terms of subscription fee, home shopping, and advertising sales based on the total subscriber base.
基金the Shanghai Excellent Young Teachers Program and the Shanghai Leading Academic Discipline Project (No. S30602)
文摘A numerical method is developed to investigate the dynamic response of cable-seabed interaction in this paper. The motion of cable is described by the Lumped Parameter Method, while the seabed, unlike the prevailing simplified model of elastic foundation, is modeled as an irregular continuous rigid surface with rebound and friction existing, and the forces exerted by the seabed consist of normal counterforce and isotropic tangential Coulomb friction resistance. To describe the detailed dynamic response, two coefficients are introduced by analogy with the theory of rigid body collision with friction. The cable-seabed kinematic and dynamic contact conditions are formulated subsequently, and are used to incorporate the seabed effect into the cable dynamics to produce a set of ordinary differential governing equations. In this paper, we employ 4th order Runge-Kutta method to solve these equations. Several simulation cases are presented to illustrate the seabed effect. The results show that friction and impact have a prominent influence on the statics and dynamics of the cable.
