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Purpose The purpose of this paper is to adopt the uses and gratifications theory to tourism.

Given the high density of urban spaces, residents and tourists share resources and infrastructure in limited spaces. The purpose of the study is to investigate the influence of residents’ perceived tourism impacts on their attitudes towards tourism growth, the effect of proximity to tourism center on residents’ attitudes, and how this effect is moderated by residents’ demographic features (age, gender, length of residence) in urban settings. A total of 251 responses were collected in downtown Greenville, a tourist zone located in the heart of Greenville, SC, USA. Using multiple regression models and ANOVA, the study suggested that (1) economic impact was the most important predictor of residents’ attitudes towards tourism growth, (2) downtown residents were more favorable of tourism growth than county residents, and (3) Age and gender moderated the effect of proximity to a tourism center on residents’ attitudes towards tourism growth.

In Multi-FA based OFDM system that processes multiple FAs in parallel, IQ imbalance components can be generated in several points, where we can largely classify IQ imbalance component occurring within single FA and IQ imbalance component occurring between multiple FAs. In order to compensate for performance degradation owing to IQ imbalance components in the Multi-FA OFDM system, we propose two stages method considering two IQ imbalance components in this paper. The first IQ imbalance component occurring within single FA is compensated by the IQ matching algorithm in time domain and the second IQ imbalance component occurring between multiple FAs is compensated by the IQ mismatching canceller in frequency domain. We propose frame structure in which the proposed algorithm is adopted and show the EVM performance on AWGN environment through link level simulation in which the IQ matcher only, the IQ canceller only and the IQ matcher and canceller are applied respectively.

In order to provide backhaul link wirelessly for emerging convergence services, we develop an OFDM-based backhaul system operating in the E-band channel. Firstly, we make our own backhaul specification considering the E band channel in which the proposed backhaul system operates, where LDPC, 1024-QAM and 2-stream transmission using dual polarizations are adopted. Based on the specification, we simulate the PER performance on AWGN and modified 3GPP channel environment respectively and implement the backhaul system on FPGA (Xilinx Virtex UltraScale xcvu440). To compensate the RF impairments, several baseband signal processing techniques such as phase tracking, IQ balancing and XPIC are used. The backhaul system we develop can support up to 25Gbps throughput in a 2GHz channel bandwidth.

Acquiring initial synchronization with auto-correlation is simple and reliable method in wireless OFDM systems. However, recent trend of making use of wide-band frequency resources and accompanying high-frequency feature makes their implementation problematic. In order to solve this difficulty in developing our wireless backhaul system, we partitioned input signal into a few slower operation paths. This paper suggests how to acquire initial synchronization in this environment with minimum hardware and achieving performance goal in desired channel environment.

The Hargreaves method provides reference evapotranspiration (ETo) estimates when only air temperature data are available, although it requires previous local calibration for an acceptable performance. This method was evaluated using the data from 71 meteorological stations in the Seolma-cheon basin (8.48 km2), South Korea, comparing daily estimates against those from the Penman‐Monteith (PM) method, which was used as the standard. To estimate reference ETo more exactly, considering the climatological characteristics in South Korea, parameter regionalization of the Hargreaves equation is carried out. First, the modified Hargreaves equation is presented after an analysis of the relationship between solar radiation and temperature. Second, parameter (KET) optimization of the regional calibration of the Hargreaves equation (RCH) is performed using the PM method and the modified equation at 71 meteorological stations. Next, an application was carried out to evaluate the evapotranspiration methods (PM, ...

Changes in climate have largely increased concentrated heavy rainfall, which in turn is causing enormous damages to humans and properties. Floods are one of the most deadly and damaging natural disasters known to mankind. The flood forecasting and warning system concentrates on reducing injuries, deaths, and property damage caused by floods. Therefore, the exact relationship and the spatial variability analysis of hydrometeorological elements and characteristic factors is critical elements to reduce the uncertainty in rainfall-runoff model. In this study, grid resolution depending on the topographic factor in rainfall-runoff models presents how to respond. semi-distribution of rainfall-runoff model using the model GRM simulated and calibrated rainfall-runoff in the Gamcheon and Naeseongcheon watershed. To run the GRM model, input grid data used rainfall (two event), DEM, landuse and soil. This study selected cell size of 500 m(basic), 1 km, 2 km, 5 km, 10 km and 12 km. According to the resolution of each grid, in order to compare simulation results, the runoff hydrograph has been made and the runoff has also been simulated. As a result, runoff volume and peak discharge which simulated cell size of DEM 500 m~12 km were continuously reduced. that results showed decrease tendency. However, input grid data except for DEM have not contributed increase or decrease runoff tendency. These results showed that the more increased cell size of DEM make the more decreased slope value because of the increased horizontal distance.

A water supply reliability is mainly influenced by water demand, reservoir storage, and inflow change caused from drought. The water supply reliability can vary depending on the method of dam operation. In Korea, the deficit-supply method which complements water deficit as water shortage occurs in downstream areas has been used for the national water resources master plan using K-WEAP, but the prime flow method, an alternative approach, would show different results of water supply reliability in comparison to the deficit-supply method. The objective of this research is to compare and analyze differences in water supply reliability according to dam operation methods. These results can be used to re-evaluate water supply reliability of dam in a circumstance considering steady dam release for instreamflow in downstream and hydroelectric power generation.

The purpose of this research is to develop an Integrated Water Resources Evaluation Index (IWREI) which can used to assess the performance of water resources projects in a regional perspective focusing on three major sectors including water use, flood, and river environment in water resources policies. The IWREI is estimated by integrating the Water Use Vulnerability Index (WUVI), the Flood Vulnerability Index (FVI), and the River Environment Vulnerability Index (REVI) which represent the vulnerability in each sector. These indices consist of total 26 indicators selected from the pressure indicators representing the causes of damages in water use, flood, and river environment, the state indicators and the response indicators. The estimated index describes the vulnerability and effectiveness of policies with five levels: Low, Medium Low, Medium, Medium High, and High. The results of evaluating total 115 hydrological units in Korea using the WUVI, FVI, REVI, and IWREI indicate that the project effectiveness in water resources policies is clearly verified by the improved index results compared to the past (early 1990s). Regional vulnerability and evaluation indices developed in this research could be used to establish goals of water resources policy and to select priority regions for project implementation.

The objective of this study is to assess the impact of potential climate change on the hydrological components, especially on the streamflow, evapotranspiration and snowmelt, by using the Soil Water Assessment Tool (SWAT) for 17 Hanriver middle watersheds of South Korea. For future assessment, the SWAT model was calibrated in multiple sites using 4 years (2006-2009) and validated by using 2 years (2010-2011) daily observed data. For the model validation, the Nash-Sutcliffe model efficiency (NSE) for streamflow were 0.30-0.75. By applying the future scenarios predicted five future time periods Baseline (1992-2011), 2040s (2021-2040), 2060s (2041-2060), 2080s (2061-2080) and 2100s (2081-2100) to SWAT model, the 17 middle watersheds hydrological components of evapotranspiration, streamflow and snowmelt were evaluated. For the future precipitation and temperature of RCP 4.5 scenario increased 41.7 mm (2100s), ＋3 ℃ conditions, the future streamflow showed ＋32.5 % (2040s), ＋24.8 % (2060s), ＋50.5 % (2080s) and ＋55.0 % (2100s). For the precipitation and temperature of RCP 8.5 scenario increased 63.9 mm (2100s), ＋5.8 ℃ conditions, the future streamflow showed ＋35.5 % (2040s), ＋68.9 % (2060s), ＋58.0 % (2080s) and ＋63.6 % (2100s). To determine the impact on snowmelt for Hanriver middle watersheds, snowmelt parameters of SWAT model were determined through evaluating observed streamflow data during snowmelt periods (November-April). The results showed that average SMR (snowmelt / runoff) of 17 Hanriver middle watersheds was 62.0 % (Baseline). The annual average SMR were 42.0 % (2040s), 39.8 % (2060s), 29.4 % (2080s) and 27.9 % (2100s) by applying RCP 4.5 scenario. Also, the annual average SMR by applying RCP 8.5 scenario were 40.1 % (2040s), 29.4 % (2060s), 18.3 % (2080s) and 12.7 % (2100s).

The quantitative analysis of evapotranspiration (ET) is a key component in hydrological studies and the establishment of water resources planning. Generally, the quantitative analysis of ET is performed by the estimation method of potential or reference ET based on meteorological factors such as air temperature, wind speed, etc. Hargreaves equation is one of empirical methods for reference ET using air temperature data. In this study, in order to estimate more exact reference ET considering climatological characteristics in Korea, parameter regionalization of Hargreaves equation is carried out. Firstly, modified Hargreaves equation is presented after the analysis of the relationship between solar radiation and temperature. Secondly, parameter () optimization of Hargreaves equation is performed using Penman-Monteith method and modified equation at 71 weather stations. Lastly, the equation for calculating using temperature data is proposed and verified. As a result, reference ET from original Hargreaves equation is overestimated or underestimated compared with Penman-Monteith method. But modified equation in this study is more accurate in the climatic conditions of Korea. In addition, the applicability of the equation between and temperature is confirmed.

The orthogonal frequency division multiplexing (OFDM) system requires precise channel estimation for better system performance. Among various channel estimation methods, the discrete Fourier transform (DFT)-based channel estimation is favored because it has simple architecture and shows as good performance as the linear minimum mean square error (LMMSE) estimation method. However, the DFT itself has its own complexity which should be overcome to achieve high speed operation as well as simple implementation. This paper suggests a practical method of DFT-based channel estimator which uses power-of 2 fast Fourier transform (FFT) instead of complicated non-power-of 2 DFT. The validity of our proposed channel estimator is proved through simulation and error vector magnitude comparison.

Drought is a hydrologic phenomenon due to the abnormal water deficiency and a natural disaster lasting for a long time through a large area. Continuous drought monitoring is very important in minimizing damage caused by severe drought. Generally, drought index is used for drought monitoring and PDSI is one of popular indices in the world. In this study, the effect of data duration is analyzed on 3 parameters (water-balance coefficient, climatic characteristic factor, and duration factor) in PDSI. The analysis shows that the effect of data duration on the climatic characteristic factor among 3 parameters is relatively clear and similar patterns are found in the other parameters at some weather stations. Therefore, PDSI parameters need to be recalculated using the observation data in Korea for the correct application of PDSI. In addition, the parameter stabilization of PDSI requires observation data with period longer than 40 years.

AWS data can be used effectively to understand the rainfall characteristics in Korea. In spite of this advantage, AWS data have been used restrictively in flood control analysis and the study on water use analysis such as water balance assessment is very insufficient. In this study, AWS data are used to analyze spatial rainfall characteristics quantitatively and water balance assessment is performed based on AWS data. Water balance assessment is carried out from year 2002 to year 2010 considering water supply networks in Korea. The analysis shows that year 2009 is the driest year during 9 years (2002~2010) and the regions with low level water supply reliability are concentrated in the west coast of Jeonnam and the upper region of the Nakdong River. As a result, the regions that have a lack of available water resources such as the coastal and insular areas are vulnerable to droughts. Therefore, regional water supply and management plans are urgently needed. Additionally, AWS data, which consider rainfall characteristics of the coastal and insular areas, can be useful in water balance assessment.

Automobile-oriented urban transport system, continued from the past in Korea, is giving rise to inefficiency and social costs in transport sector. With revitalizing usage of bicycle, human-powered transport mode, it is possible to enhance sustainable green growth, improvement of the city-competitiveness, and the quality of life. In this study, the possibility of bicycle usage promotion in Korean cities is examined at 7 points of views. As a result, though the bicycle usage is low now, we figured that there are many positive signs to increase bicycle usage in Korea. Also, we draw a diverse key policies for building green urban transport system that bicycle have a most important role on transport system. So policies to promote bicycle usage are reviewed to analyze on bicycle-oriented 5 cities, in which have high bicycle mode share. By this review, this study could draw 41 key effective policies to 3 aspects (bicycle infrastructure, safety and promotion, and policy sustainability). In addition to, importance of 21 key effective policies about bicycle infrastructure is suggested as considering city's characteristics.

An integrated water resources management is highly required to use efficient water and preserve water quality due to the limits of water resources development and water pollution. K-WEAP was developed, which supports the water resources planning and evaluation within a fully integrated interactive system. In this study, we present three applications of K-WEAP. First, we examined the usefulness of K-WEAP as a water resources planning tool through its application to the National Water Resources Plan. Second, the conjunctive use of surface water and groundwater in the Geum river basin with K-WEAP was evaluated, and its results show how to support to set up a sustainable groundwater management plan. Finally, we confirmed the function of the integrated water quantity and quality management in K-WEAP, which conducted by comparing the simulated results of water quality in both QUAL2E and K-WEAP.

This study presents the alteration of flow regime by effects of dams and water use in the Geum River Basin. The surface water use rate and the Impounded Runoff (IR) index were examined to assess the pressure indicators of the flow alteration. We applied the flow duration curve, flow regime coefficient, flood and low-flow frequency analysis as well as Range of Variability Approach (RVA) to investigate the quantitative changes in natural flow regimes. The results indicate that the high flow decreased and low flow increased respectively compared to the natural flow regimes at eight gauging stations. The Geum river is regulated by 139 dams and reservoirs storing 24% of the annual mean discharge and has high surface water use rate of 36%. These indicators are main pressure factors to alter flow regimes.

The 3-dimensional beamforming is a highly attractive issue in 5G telecommunication. Equipped with 2-dimensional antenna arrays, it allows vertical sectorization within a cell as well as horizontal one, by making a beamforming zone for the corresponding sector. However, there is considerable inequality among the areas of beamforming zone. Since the farther from the base station, the bigger the beamforming zone area is, the farther beamforming zone area is likely support more users than nearer beamforming zone. In this paper, we propose to utilize carrier aggregation (CA) from additional base stations for relieving the uneven beamforming zone area problem and prove this method is more efficient in improving cell throughput especially in mmWave environment. Even if the additional base station is more simple type which offers only a few beamformings, it can effectively improve the equality of UE's radio resource occupation.

3D beamforming is a highly attractive issue in 5G telecommunication. Equipped with 2D antenna arrays, it allows vertical sectorization within a cell as well as horizontal one, by making a beamforming zone for the corresponding sector. However, there is considerable inequality among the areas of beamforming zone. The farther from the base station, the bigger the beamforming zone area is. In this paper, we propose to utilize carrier aggregation (CA) for relieving the uneven beamforming zone area problem and prove this method is more efficient in improving cell throughput especially in mmWave environment.

The efficient management strategies of reservoirs in periods of drought event are an essential element for drought planning. A Water Supply Capacity Index (WSCI) has been developed for the evaluation and effective monitoring of the supply capacity of a re