• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.10
• /
• pp.2039-2044
• /
• 2009

The PSK carrier signal recovery circuit using multi-layer coupled line was analyzed and designed. The fabricated carrier recovery 6 port element with multi-layer coupled line structure gets the simple architecture. It is possible to implement the carrier signal recovery circuit of the same structure with the multi-layer six port phase correlator of the direct receiver front-end. Based on the analysis of RML carrier recovery circuit using the multi-layer coupled line 6-port phase correlator, the multi-layer coupled line carrier signal recovery structure for multi-mode coherent demodulation was proposed. The fabricated multi-layer coupled line carrier signal recovery circuit for quadrature phase shift-keying shows a good carrier signal characteristic with a constant phase and phase error below ${\pm}3o$.

• Applied Chemistry for Engineering
• /
• v.16 no.2
• /
• pp.200-205
• /
• 2005

We have prepared the porous carrier that has high capacity for immobilization of microorganisms and adsorption capacity for cation using fly ash in the previous work. In this study, we investigated the characteristics of piggery wastewater treatment in comparison with commercial carrier and conventional activated sludge process by continuous-flow fixed biofilm process in laboratory scale at the same experimental conditions to develop the biofilm process using porous fly ash carrier for wastewater treatment. As a result, the prepared fly ash carrier showed that removal efficiency of COD, TN and $NH_4{^+}-N$ items were 80%, 77% and 65%, respectively, which were higher efficiency than the commercial carrier and conventional activated sludge process. And the result of measurement for immobilized microorganisms after treatment showed higher capacity than the commercial carrier, and it was confirmed by SEM observation on fly ash carrier that the colony of microorganisms was stably formed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.3
• /
• pp.49-56
• /
• 2022

ROK Navy intends to secure the Korean-type aircraft carrier in order to effectively prepare for various future security threats. In general, the Korean national competency is considered to be at the level of having an aircraft carrier, but it is unclear what scale aircraft carrier would be appropriate. In this study, the efficiency was evaluated through the relative comparison between national competency(national power, economic power) and the scale of aircraft carriers, and the optimal scale of the Korean-type aircraft carrier that could be acquired was presented. A DEA(Data Envelopment Analysis) model was applied to aircraft carriers(19 aircraft carriers in 11 countries) currently in operation and scheduled to be possessed in the world. As input variables, CINC(Composite Index of National Capability) and GDP(Gross Domestic Product), which are the most widely used as indicators of national and economic power, and as output variables, the full-load displacement, length, and width of aircraft carriers were selected. ARIMA(short-term within 5 years) and simple regression(long-term over 5 years) were used to estimate the future national competency of each country at the time of aircraft carriers acquisition. The relative efficiency score of the Korean-type aircraft carrier currently being evaluated is 1.062, and it was evaluated as small-scale aircraft carrier compared to the national competency. Based on Korean national competency, the optimal scale of the Korean-type aircraft carrier calculated by aggregating benchmark groups, is 58,308.1 tons of full-load displacement, 279.4m in length, and 68.3m in width.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.10
• /
• pp.1427-1435
• /
• 2002

The main aim of the present article is numerically to investigate the micro-scale heat transfer phenomena in a silicon microstructure irradiated by picosecond-to-femtosecond ultra-short laser pulses. Carrier-lattice non-equilibrium phenomena are simulated with a self-consistent numerical model based on Boltzmann transport theory to obtain the spatial and temporal evolutions of the lattice temperature, the carrier number density and its temperature. Especially, an equilibration time, after which carrier and lattice are in equilibrium, is newly introduced to quantify the time duration of non-equilibrium state. Significant increase in carrier temperature is observed for a few picosecond pulse laser, while the lattice temperature rise is relatively small with decreasing laser pulse width. It is also found that the laser fluence significantly affects the N 3 decaying rate of Auger recombination, the carrier temperature exhibits two peaks as a function of time due to Auger heating as well as direct laser heating of the carriers, and finally both laser fluence and pulse width play an important role in controlling the duration time of non-equilibrium between carrier and lattice.

• Journal of the Korean Society of Physical Medicine
• /
• v.5 no.3
• /
• pp.323-330
• /
• 2010

Purpose : The purpose of this study was to evaluate the effects of muscle activation of neck, lumbar and low limb by using baby carrier with arms during walking. Methods : Twenty healthy and young females who brought up infants and had no musculoskeletal disorders of neck, lumbar and low limb were recruited for this study. They were instructed to perform muscle activation of neck, lumbar and low limb using the baby carrier with and without arms during walking. ProComp $infiniti^{TM}$ (Thought Technology Ltd., Canada) was used to measure the muscle activity of neck, lumbar and lower extremity muscles. Results : Activation of neck paraspinalis muscle was significantly increased using baby carrier with arms and there was a significant increase on erector spinae muscle activation by using anterior baby carrier. Conclusion : These results indicate that the muscle activation was changed by arms assist and the position of using baby carrier. Therefore, it could be considered relationship of muscle activation and musculoskeletal demage as carrying baby.

• Journal of KIISE:Information Networking
• /
• v.37 no.4
• /
• pp.307-311
• /
• 2010

Most wireless ad hoc networks use sender-centric carrier sensing where a data sender determines the transmission timing through channel assessment. However, sender-centric carrier sensing suffers from both exposed and hidden terminal problems even with physical and virtual carrier sensing. In this paper, we propose a new receiver-centric carrier sense (RCS) technique where a data receiver triggers packet transmission based on local channel assessment. Through both numerical analysis and simulation studies, we show that the proposed RCS achieves up to 20.9% higher throughput than previous receiver-centric approaches.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1995.09a
• /
• pp.57-71
• /
• 1995

A simple mathematical model for gacilitated mass transport with a fixed site carrier membrane was derived by assuming an instantaneous, microscopic concentration (activity) fluctuation, The concentration fluctuation, developed due to reversible chemical reaction between carrier and solute, could acuse the higher chemical potential gradient and the facilitated transport. For mathematical formulation, an analogy was employed between the mass transfer for the facilitated transport with fixed site carrier membrane and the electron transfer in a parallel resistor-capacitor (RC) circuit. For the single RC model, it was assumed that a single capacitor represented the total carrier and a solute could not inter-diffuse between matrix and carrier, allowing only two diffusional pathways, This assumption was relaxed by adopting a serial combination of the parallel RC circuit. Here, a solute diffuses in two elements (matrix or carrier) can exchange its pathway, exhibiting four diffusional pathways. The current models were examined against experimental data and the agreement was exceptional.

• International Commerce and Information Review
• /
• v.8 no.4
• /
• pp.147-156
• /
• 2006

In all cargo cases one of the first things the person handling the claim must do is decide who is potentially liable as a carrier of the goods. This issue arises because bills of lading often do not identify the carrier. The "carrier" could be the shipowner or the charterer or both. The issue of the identity of the "carrier" is a question of fact. The question to ask in each case is who undertook or agreed to carry and deliver the goods. The answer to this question will largely depend on the facts. The shipowner is almost always liable as a carrier under Common law provided there is no demise charter of the ship. The more recent case law, however, suggests that in the usual situation both the charterer and shipowner will be liable. Accordingly, both the owner and charterer should be put on notice of any claim and, in the event an extension of suit time is required, the extension should be obtained from both. An alternative method by which the charterer can avoid liability is to insert and 'Identity of Carrier' clause in the bill of lading.

• Journal of Advanced Marine Engineering and Technology
• /
• v.36 no.6
• /
• pp.823-829
• /
• 2012

Data communications networks at sea in the future can be modelled by overlapped MANET networks with Broadband Wireless Access carriers. A novel routing scheme (CPLR) is proposed in this paper, which finds out an optimal route by selecting an optimal carrier for each hop in routes based on carrier preferences of each application, and locations of ships as well. As distances between each ships and destination ships are considered in this scheme, routing can be done much faster. Performance is compared with that of the CPR (only Carrier Preference-based Routing Scheme), and it shows some improvements.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.3
• /
• pp.131-140
• /
• 2015

The purpose of this study is to predict the fatigue life of a planet carrier of a slewing reducer for a tower crane. To predict the fatigue life of the carrier, the inertia endurance test was carried out, and then the input torque profile for the reducer was obtained. The load profile acting on the planet pins that assembled the carrier was calculated from the measured input torque profile using commercial gearbox analysis software. The stress profiles of the carrier weak points were analyzed from the calculated load profile and boundary conditions using commercial FE software, and the stress cycles were determined using the rainflow counting method. Finally, the fatigue life of the carrier was predicted using the equivalent stress range by considering the effect of mean stress, and an S-N curve was drawn up using the GL guideline and the cumulative damage law.