김용완 Kim Yong Wan , 홍석영 Hong Suk Young , 장민원 Jang Min Won

DOI: JKWST Vol.53(No.5) 1-7, 2011

---

The objective of this study is to decide a spatial interpolation method on temperature data for the suitability analysis of garlic cultivation. In Korea, garlic is the second most cultivated condiment vegetable after red pepper. Nowadays warm-temperate garlic faces potential shift of its arable area according to warmer temperature in the Korean Peninsula, and the change can be drawn with the precise temperature map derived from interpolation on point-measured data. To find the preferable interpolation method in cases of germination and vegetative period of the garlic, different approaches were tested as follows: Inverse Distance Weighted (IDW), Spline, Ordinary Kriging (OK), and Universal Kriging (UK). As a result, IDW and UK show the lowest root mean square errors as for the germination and vegetative seasons, respectively. However, statistically significant difference was not revealed among the applied methods regarding the germinating period. Eventually this will contribute to mapping the suitable lands for the cultivation of warm-temperate garlic reasonably.

전지홍 Jeon Ji-hong , 김태동 Kim Taedong , 최동혁 Choi Donghyuk

DOI: JKWST Vol.53(No.5) 9-16, 2011

---

Curve Numbers (CN) for the combination of land use and hydrologic soil group were regionalized at Imha Watershed using Long-term Hydrologic Impact Assessment (L-THIA) coupled with SCE-UA. The L-THIA was calibrated during 1991-2000 and validated during 2001-2007 using monthly observed direct runoff data. The Nash-Sutcliffe (NS) coefficients for calibration and validation were 0.91 and 0.93, respectively, and showed high model efficiency. Based on the criteria of model calibration, both calibration and validation represented ‘very good’ fit with observe data. The spatial distribution of direct surface runoff by L-THIA represented runoff from Thiessen pologen at Subi and Sukbo rain gage station much higher than other area due to the combination of poor hydrologic condition (hydrologic soil C and D group) and locality heavy rainfall. As a results of hydrologic condition and treatment for land use type based on calibrated CNs, forest is recommended to be hydrologically modelled dived into deciduous, coniferous, and mixed forest due to the hydrological difference. The CNs for forest and upland showed the poor hydrologic condition. The steep slope of forest and alpine agricultural field make high runoff rate which is the poor hydrologic condition because CN method can not consider field slope. L-THIA linded with SCE-UA could generated a regionalized CNs for land use type with minimized time and effort, and maximized model's accuracy.

이정우 Lee Jeong Woo , 박찬기 Park Chan Gi , 김종옥 Kim Jong Ok , 이승기 Lee Seung Kee , 김필식 Kim Pil Sik

DOI: JKWST Vol.53(No.5) 17-23, 2011

---

Steel clapping plate is used to connecting rubber body in rubber dam. However, once the steel clapping plate corrodes, it may cause faults, such as the same problems experienced by typical reinforcing steel. This study evaluated the applicability of glass fiber reinforced polymer composite(GFRP) clapping plate as a substitute for steel clapping plate. Absorption and load test were conducted to evaluate the decrease in durability of GFRP clapping plate exposed to deterioration environments. In the durability test results, the absorption rate of GFRP clapping plate was appeared as 0.6∼1.0% in 50 day of immersion time. Also, the fracture load decreased with accelerated degradation environment exposure. Moreover, the absorption rate in GFRP clapping plate increased as degradation progressed, reducing the fracture load.

연규석 Yeon Kyu Seok , 김용성 Kim Yong Seong , 차진윤 Cha Jin Yun , 손승완 Son Seung Wan

DOI: JKWST Vol.53(No.5) 25-33, 2011

---

In this paper, the effects of aggregate and curing temperature on strength development characteristics of UP (Unsaturated Polyester)-MMA (Methyl Methacrylate) based polymer mortar under sub-zero temperature are experimentally investigated to provide a criterion for repair and production of precast products. The result showed that the setting time of the binder was 4 minutes at 20 °C whereas 35 minutes at －20 °C. The result also revealed that the compressive, flexural, and splitting tensile strengths of UP-MMA based polymer mortar significantly decreased as the aggregate and curing temperatures decreased. However, sufficient strengths which can be implemented in actual practices - 36.6 MPa of compressive strength, 6.11 MPa of flexural strength, and 5.81 MPa of splitting tensile strength - were obtained even though both aggregate and curing temperatures were －20°C. Strength development of polymer mortar is largely affected by curing temperature rather than aggregate temperature. It was found that the effects of aggregate temperature on strength development become smaller as the curing temperature becomes lower. Also, toughness, a ratio of compressive strength to flexural strength, increased from 3.5 to 5.9 as both aggregate and curing temperatures decreased from 20 °C to －20 °C.

정충길 Jung Chung Gil , 박종윤 Park Jong Yoon , 이지완 Lee Ji Wan , 정혁 Jung Hyuk , 김성준 Kim Seong Joon

DOI: JKWST Vol.53(No.5) 35-42, 2011

---

This study is to check the applicability of SWAT-APEX (Soil and Water Assessment Tool-Agricultural Policy / Environmental eXtender) model as combined watershed and field models by applying the APEX to paddies in a watershed (465.1 ㎢) including Yedang reservoir. Firstly, the SWAT were calibrated with 3 years (2000～2002) daily streamflow and monthly water quality (T-N and T-P) data, and validated for another 3 years (2003～2005) data. The average Nash-Sutcliffe model efficiency (ME) of streamflow during validation was 0.73, and the coefficient of determination (R²) of T-N and T-P were 0.77 and 0.73 respectively. Next, running the SWAT-APEX model with the SWAT calibrated parameters for paddies, the R² of T-N and T-P were 0.80 and 0.76 respectively. The results showed that SWAT-APEX model was more correctly predicted for T-N and T-P loads than SWAT model. The difference results between watershed and field models was predicted to have substantial impact on NPS loads, especially on T-N and T-P loads. Therefore, to improve negative NPS load simulations should be considered the model characteristics as simulating mechanism to properly select the NPS model for agricultural watershed.

남원호 Nam Won-ho , 김태곤 Kim Taegon , 최진용 Choi Jin-yong , 김진택 Kim Jin-taek , 나민철 La Min-chul

DOI: JKWST Vol.53(No.5) 43-51, 2011

---

Irrigation facilities are spread over demand area in a low density and exposed in the field requiring efficient operation and maintenance. Thus, it could be more efficient to manage an irrigation system when it is with wireless sensor network (WSN) using RFID (Radio Frequency Identification) application. A WSN, a kind of ubiquitous sensor network composed of wireless network, RFID and database management system was developed for agricultural water management in terms of operational status and maintenance requirements. Identification code for RFID tag was designed and an application for RFID reader was developed for field data collection, and a database management system was constructed for managing irrigation facility attributes. The system was installed in I-dong irrigation districts in Gyounggi-province, Korea and the operated results showed the applicability of the WSN for agricultural water management.