• Journal of Power Electronics
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• v.13 no.2
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• pp.296-303
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• 2013

This paper proposes a high efficiency three-phase cascaded phase shifted H-bridge multi-level inverter without DC/DC converters for grid-tied multi string photovoltaic (PV) applications. The cascaded H-bridge topology is suitable for PV applications since each PV module can act as a separate DC source for each cascaded H-bridge module. The proposed phase shifted H-bridge multi-level topology offers advantages such as operation at a lower switching frequency and a lower current ripple when compared to conventional two level topologies. It is also shown that low ripple sinusoidal current waveforms are generated with a unity power factor. The control algorithm permits the independent control of each DC link voltage with a maximum power point for each string of PV modules. The use of the controller area network (CAN) communication protocol for H-bridge multi-level inverters, along with localized PWM generation and PV voltage regulation are implemented. It is also shown that the expansion and modularization capabilities of the H-bridge modules are improved since the individual inverter modules operate more independently. The proposed topology is implemented for a three phase 240kW multi-level PV power conditioning system (PCS) which has 40kW H-bridge modules. The experimental results show that the proposed topology has good performance.

• Physical Therapy Korea
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• v.23 no.2
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• pp.93-99
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• 2016

Background: Parametric statistical procedures are typically conducted under the condition in which a sample distribution is statistically identical with its population. In reality, investigators use inferential statistics to estimate parameters based on the sample drawn because population distributions are unknown. The uncertainty of limited data from the sample such as lack of sample size may be a challenge in most rehabilitation studies. Objects: The purpose of this study is to review the bootstrapping method to overcome shortcomings of limited sample size in rehabilitation studies. Methods: Articles were reviewed. Results: Bootstrapping method is a statistical procedure that permits the iterative re-sampling with replacement from a sample when the population distribution is unknown. This statistical procedure is to enhance the representativeness of the population being studied and to determine estimates of the parameters when sample size are too limited to generalize the study outcome to target population. The bootstrapping method would overcome limitations such as type II error resulting from small sample sizes. An application on a typical data of a study represented how to deal with challenges of estimating a parameter from small sample size and enhance the uncertainty with optimal confidence intervals and levels. Conclusion: Bootstrapping method may be an effective statistical procedure reducing the standard error of population parameters under the condition requiring both acceptable confidence intervals and confidence level (i.e., p=.05).

• Environmental and Resource Economics Review
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• v.18 no.3
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• pp.393-430
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• 2009

This study uses a computable partial-equilibrium model of the U.S. energy industry to evaluate sulfur dioxide concentrations under two environmental policies. The policies, generator-level emission caps and tradable allowances, are selected to yield identical aggregate emissions. Regional concentrations are found to vary across the two policies significantly. These variations translate into different losses for individual states, and, nationwide, to differences of hundreds of millions of dollars in aggregate health damages. Emission caps outperform allowances by $452 million. Caps favor the southwestern, south-central and southeastern states, where they deliver $840 million lower damages than the other policies, while they deliver $390 million higher damages In northern and northeastern states.

• Economic and Environmental Geology
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• v.9 no.3
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• pp.135-141
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• 1976

The gamma-gamma logging method appplying in geophysical research are presented in this paper_ The logging probe assembly was designed which permits changing the source-to-detector spacing while conditions of proceeding ${\gamma}-{\gamma}$ logging, which a collimated gamma ray source ($^{60}Co$, 0.5mCi and/or 2 mCi) is separated from the scintillation detector as shown in Fig. 2 and 3, size is 6.0 cm in diameter and 120.0 cm in long and the exposed parts are made of stainless steel pipe. The results is confirmed by the experiment performed mainly in granite rock where a slightly constant shape was obtained but sometimes was shown sharpness shape for the measured scattered gamma-ray intensity. Consequently, the experimental results are obtained an adequate intensity of scattered gamma-rays and favourable response to density change, and also very closely correspond to between core samples of the test boring and to used this method of ${\gamma}-{\gamma}$ logging in the test bore-hole of the strata.

• International Journal of Concrete Structures and Materials
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• v.8 no.2
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• pp.99-116
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• 2014

The American Concrete Institute (ACI) 318-11 permits the use of the moment magnifier method for computing the design ultimate strength of slender reinforced concrete columns that are part of braced frames. This computed strength is influenced by the column effective length factor K, the equivalent uniform bending moment diagram factor $C_m$ and the effective flexural stiffness EI among other factors. For this study, 2,960 simple braced frames subjected to short-term loads were simulated to investigate the effect of using different methods of calculating the effective length factor K when computing the strength of columns in these frames. The theoretically computed column ultimate strengths were compared to the ultimate strengths of the same columns computed from the ACI moment magnifier method using different combinations of equations for K and EI. This study shows that for computing the column ultimate strength, the current practice of using the Jackson-Moreland Alignment Chart is the most accurate method for determining the effective length factor. The study also shows that for computing the column ultimate strength, the accuracy of the moment magnifier method can be further improved by replacing the current ACI equation for EI with a nonlinear equation for EI that includes variables affecting the column stiffness and proposed in an earlier investigation.

• International Commerce and Information Review
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• v.11 no.3
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• pp.287-309
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• 2009

There were many changes regarding Negotiation of document under UCP 600. First of all, the definition of Negotiation was changed. The UCP 500 stated "Negotiation means the giving of value for drafts and documents by the bank authorized to negotiation", but the UCP 600 defines "negotiation" as following "negotiation means the purchase by the nominated bank of drafts and/or documents under a complying presentation". Under the UCP 600 the meaning of negotiation was more clear than UCP 500. Second UCP 600 permits all deferred payment credits be discountable or negotiable. This amended rule equated the deferred payment credit with banker's acceptance credit which was contrary with the nature and the practice of former deferred payment credit transaction. Third, UCP 600 has also provided for reimbursement rights for nominated banks and a conceptual basis for protecting nominated banks against beneficiary fraud. In this paper, the problems regarding negotiation of document under UCP600 was studied and the solutions for the problems occurring in appling UCP 600 in practical field was provided.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.1
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• pp.1-6
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• 1993

The maxillary squamous cell carcinoma is major part of maxillary malignant tumor. The treatment of maxillary malignancy tumor is the maxillectomy in combination with radiation therapy and chemorherapy. When tumor invasion is occured to the orbit, orbital exenteration is required. But if the periosteum of the orbital floor is intact, the orbit can be preserved. There are many orbital floor reconstruction materials for the prevention of ptosis of the orbital content. The patients on this paper were diagnosised as squamous cell carcinoma on maxilla, we performed the partial maxillectomy including the orbital floor, and we used temporalis muscle-coronoid process flap for the reconstruction of the orbital floor after partial maxillectomy and obtained good esthetic and functional results, as followed. 1. We obtained sufficient flap width for defect of orbital floor. 2. It permits good blood supply and no necessary other donor site. 3. It gives a solid base for the support the globe and the orbital floor. 4. It gives minimal postoperative morphorogical defect and functional disturbance.

• Journal of Magnetics
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• v.21 no.3
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• pp.450-459
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• 2016

Experimental results and data of numerical simulations are presented, concerning generation of wideband radio frequency (RF) oscillations in a nonlinear transmission line (NLTL) which contains a pre-magnetized core of ferrite material. Emphasis is made on the means for extracting the RF signal from the line, in order to radiate it into free space. Antennas of two types that can be used for the purpose are considered, both featuring a coaxial design. This permits availing of the principal advantages of coaxial systems, such as operation in the mode of a traveling TEM wave; wide range of the transmitted frequencies, and a reasonably simple design. The antennas studied, specifically a disc-cone dipole (DCD) and an impulse reflector antenna ('Half-IRA', or HIRA type) differ significantly in effective width of the radiated spectrum and in spatial characteristics of the radiated field in far region.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.111-117
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• 2006

Song-do City is a newly constructed city built on land reclaimed from the seaside and the surrounding area. Its development involved a long process since the basic plans for reclamation of the publicly owned seaside area in Song-do were drawn up in September 1979. However, if we take a look at the overall status of the project as it is carried on at present, it is hard to deny that the project is trapped inside the same legal restrictions as are all other existing cities, which permits Song-do City to meet only very minimum standards. This study intends to analyze and assess the Song-do City's environmentally friendly construction and to rate its current development status, exposing any problems and offering alternative solutions. In this paper, the current state of constructions in Song-do City were reviewed. Then a quantitative analysis and assessment for the Song-do City constructions of apartments, complex buildings, office buildings, and school facilities were conducted by using green building certification criteria. Finally the synthetic results of environmental performance evaluation for Song-do city constructions and follow-up suggestions were described.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.454-461
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• 2010

The new SOLAS regulation permits the alternative design approach for the approval of designs which deviate from those where prescriptive rules apply. The new approach is being promoted by recent advances of noble designs such as those employing large public spaces in passenger ships. From the respect of fire safety, it is needed to show that the level of safety of new design is equivalent to what can be achieved from the prescriptive rules where the fire simulation is regarded to be the essential tool. This paper provides an overview of the process of performance-based design of the smoke extraction system in a cafeteria of a ROPAX. FDS, a CFD fire simulation software is used to show that the field-model software can improve the fire safety over what are expected from prescriptive rule sets or zone-model application.