• Journal of the Society of Naval Architects of Korea
• /
• v.43 no.5 s.149
• /
• pp.597-603
• /
• 2006

The estimations of distributed and joint-excited input power for Power Flow Analysis are accomplished in this paper. Using Fourier transform, the displacements of infinite structures are derived, and the input power of distributed excitation can be estimated. The obtained results compare the real input power with the estimation of input power. When the exciting force acts on the joint of coupled structures, it is estimating the power that is transferred to each structure. Appling this input power, the results of energy density and intensity of Power Flow Analysis can be compared with the classical solutions.

• Transactions of Materials Processing
• /
• v.18 no.5
• /
• pp.385-391
• /
• 2009

An adhesively bonded power steering cylinder with a steel tube and an aluminum bracket was developed to reduce the weight of steering systems. To achieve the joint strength between the steel tube and of the aluminum bracket, the shape aluminum bracket re-designed by using the FE-analysis. Fracture behavior of the adhesive layer was considered by a cohesive zone model(CZM), which is based on the two-parameter fracture phenomenon with critical stress and fracture toughness. From the result of FE-analysis with CZM, re-designed power steering cylinder satisfied the desired joint strength for axial and torsion modes. And its joint strength was verified by the fracture test in each mode.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.2
• /
• pp.167-172
• /
• 2014

The purpose of this study was to investigate walking standard time and joint powers of the lower extremities on the changes of illuminations in the elderly women. Ten older women ($70.90{\pm}3.28$ years, $154.70{\pm}3.47$ cm, $53.80{\pm}5.39$ kg) with normal vision and no gait disabilities participated in this study. All the experiments were performed on a level walkway from low to high lighting (six conditions). A 3-dimensional motion capturing system, force-plate, and EMG were used to acquire and analyze walking motion, force, and muscle activity data; the sampling frequency was 100 Hz, 1000 Hz and 1000 Hz respectively. To test the differences on walking standard time and joint powers of the lower extremities between the six lighting conditions, one-way repeated ANOVAs were evaluated. The following results were drawn: First, mean standard time was about 1.3 sec/stride, and velocities were smaller with lighting increasing except 100 Lx. Second, the joint power patterns of ankle and knee were not consistent, but only hip joint power was a greatest in 6 Lx and a smallest in 400 Lx. Third, standard times(100 Lx<300 Lx, 400 Lx) were statistically significant, and hip joint max powers (100 Lx>others) were also statistically significant. But ankle and knee joint max power were not statistically significant. These results showed that standard times from low to high lighting were not consistent, and hip joint of 100 Lx has a greatest rotational torque. We suggested that gait strategies of them as to changing illuminations were not consistent and findings may represent a lack of adaptability in the elderly women.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.5 no.4
• /
• pp.265-277
• /
• 1993

Recently, underground transmission system is growing continuously according to the electric power demand increase in the downtown area. Even if domestic cable makers are manufacturing 154kV oil filled cable and joint, the design technology of cable-joint has not been fully self-reliance. This study is aimed at the detail heat transfer analysis of 154kV cable-joint. So, that is cut into the five sections in order to analyze a conjugate natural convection in two dimensional $r-{\theta}$ coordinate. The streamline and temperature distributions are obtained for each sections. Also the changes of those are analyzed with respect to the variation of transmission currents and cable-joint surface heat transfer coefficients. The same analyses are also shown in view point of the maximum temperature of conductor and local equivalent conductivity.

• Strategy21
• /
• s.37
• /
• pp.193-241
• /
• 2015

China, Japan and Korea are the world's top 10 energy consumers, and so very interested in the development of seabed hydrocarbon resources in order to meet their energy demands. The East China Sea is the tri-junction area where three countries' entitlements on the maritime boundaries are overlapped. There are abundant oil reserves in the East China Sea, and therefore competitions among countries are growing to get control of them. Although these countries have concluded the bilateral agreements to jointly develop resources in the East China Sea, they do not function as well. Because joint development and management of seabed petroleum resources can lead to stable development system, and to lower possibility of legal and political disputes, the needs for joint development agreement among three countries are urgent. Meanwhile, Northeast Asian seas are semi-closed seas, which are geographically closed and vulnerable to marine pollution. Moreover there are a lot of nuclear power plants in coastal area, and seabed petroleum resources are being developed. So it is likely to occur nuclear and oil spill accidents. Fukushima nuclear disaster and Bohai Bay oil spill accident in 2011 are the cases to exhibit the potential of major marine pollution accidents in this area. It is anticipated that the risks become higher because power plants and offshore oil platforms are extending gradually. Therefore, the ways to seek the joint marine environmental protection agreement focused on regulation of nuclear power plant and offshore oil platform have to be considered. In this paper, we try to find the way to make joint development and joint environmental protection agreement in Northeast Asian seas. We concentrate on the measure to drive joint development of seabed petroleum deposits in East China Sea's overlap area, despite of maritime delimitation and territorial disputes, and we try to drive joint marine environmental protection system to respond to marine pollution and accidents due to offshore oil platform and nuclear power plants. Through these consideration, we seek solutions to deal with lack of energy, disputes of maritime territorial and boundary delimitation, and marine pollution in Northeast Asia.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.285-286
• /
• 2008

In practical applications of HTS tapes for electric devices such as coils and power cables, the jointing of HTS tapes is needed. In magnet applications superconducting joints are needed to achieve very low resistance at the joint, but for power device applications, a slightly higher joint resistance may be acceptable. In this study, an economical joint with good mechanical and electrical integrity could be achieved for Bi-2223 tapes which can be applicable to electric power applications. A lap joint method has been used. The joint resistance and strength of the jointed Bi2223 tapes have been evaluated. Electro-mechanical properties of the joint sample under tension have been examined and compared with the case of the single tapes.

• Plant Journal
• /
• v.7 no.3
• /
• pp.42-47
• /
• 2011

One of domestic power generation companies, Korea East-West Power Corporation(EWP) had no performance in overseas business just two short years ago. However, EWP has accomplished breakthrough results with the profit of KRW 17.8 billion in 2010, only overseas business part. With overseas power plant growing fast, there is a possibility that EWP may face the limitation of sustainable growth with the current low income structure, which is mainly focused on commissioning and power plant management. Accordingly, this study was made on overseas biomass plant business participation plan through the establishment of joint venture. The characteristics of a joint venture establishment was searched, choosing business partner; the ideas of how to organize a joint venture was drawn, what the role of each partner in joint venture is, and what proper capital share is; and chose business field, considering changing global energy mix, renewable energy market scale, and growth prospects. Considering government policy for renewable energy vitalization and renewable energy market share, We chose the European union as a market to which our business entered.

• Journal of Communications and Networks
• /
• v.18 no.3
• /
• pp.375-386
• /
• 2016

Most existing studies on broadcast services in orthogonal frequency division multiplexing (OFDM) systems have focused on how to allocate the transmission power to the subcarriers. However, because a broadcasting system must guarantee quality of service to all users, the performance of the broadcast service dominantly depends on the channel state of the user who has the lowest received signal-to-noise ratio among users. To reduce the effect of the worst user on the system performance, we propose a joint delivery scheme of unicast and broadcast transmissions in OFDM systems with broadcast and unicast best-effort users. In the proposed joint delivery scheme, the BS delivers the broadcast information using both the broadcast and unicast subcarriers at the same time in order to improve the performance of the broadcast service. The object of the proposed scheme is to minimize the outage probability of the broadcast service while maximizing the sum-rate of best-effort users. For the proposed joint delivery scheme, we develop an adaptive power and subcarrier allocation algorithm under the constraint of total transmission power. This paper shows that the optimal power allocation over each subcarrier in the proposed scheme has a multi-level water filling form. Because the power allocation and the subcarrier assignment problems should be jointly solved, we develop an iterative algorithm to find the optimal solution. Numerical results show that the proposed joint delivery scheme with adaptive power and subcarrier allocation outperforms the conventional scheme in terms of the outage probability of the broadcast service and the sum-rate of best-effort users.

• Journal of Communications and Networks
• /
• v.14 no.3
• /
• pp.257-266
• /
• 2012

A decode-and-forward two-way relay system benefits from orthogonal frequency division multiplexing (OFDM) and relay transmission. In this paper, we consider a decode-and-forward two-way relay system over OFDMwith two strategies: A joint subcarrier matching algorithm and a power allocation algorithm operating with a total power constraint for all subcarriers. The two strategies are studied based on average capacity using numerical analysis by uniformly allocating power constraints for each subcarrier matching group. An optimal subcarrier matching algorithm is proposed to match subcarriers in order of channel power gain for both transmission sides. Power allocation is defined based on equally distributing the capacity of each hop in each matching group. Afterward, a modified water-filling algorithm is also considered to allocate the power among all matching groups in order to increase the overall capacity of the network. Finally, Monte Carlo simulations are completed to confirm the numerical results and show the advantages of the joint subcarrier matching, power allocation and water filling algorithms, respectively.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1907-1909
• /
• 1996

In this paper, ultrsonic detection properties at a premolde joint utilized in a 23kV cables are studied. In a experiment a artificial defect within a joint and a measuring system are builded for generating discharges, gathering data about a detection properties, respectively. The experiment results show that one point detection is not allowed for monitoring a global status of a joint discharges and a detection sensitivity is less than 100pC. And also the attenuation and wave speed at the material of joint insulator are obtained.