Papers - OKAZAWA Hiromu
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Educational Material Research on the Color of Crayfish for Conversion to Edible Resources "jointly worked" Reviewed International journal
Saki Higuchi, Honami Ono, Hiroaki Honda, Sarvesh Maskey, Akira Kurosawa, Toshihiro Suzuki, Nobuyuki Takahashi, Hiromu Okazawa and Kouji Takeda
International Journal of Environmental and Rural Development 14 ( 1 ) 98 - 105 2023.06
Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation
The crayfish (Procambarus clarkii) is an invasive alien species consumed as a food source worldwide. However, there is an extremely low demand for it as a food resource in Japan, and it is typically targeted for extermination. One reason for the lack of progress in considering crayfish a sustainable food resource is limited education on the issue during secondary education programs. It is well known that astaxanthin is the pigment responsible for the body color of common red crayfish and crustaceans such as shrimp and crabs. At the same time, while there are ample study materials on plant pigments in the science education curriculum in junior high and high schools in Japan, there are no such materials to our knowledge that focus on animal pigments. Therefore, this research sought to develop teaching materials to deepen understanding of color as a food component of crayfish through an experiment involving extracting and separating their pigments. Using pigments extracted from red crayfish exoskeletons, we developed experimental teaching materials to observe astaxanthin by employing thin-layer chromatography and high-performance liquid chromatography. In addition, an experiment was conducted to observe the effect of different foods on crayfish body color. For the experiment, food was developed to make crayfish bodies white (decolorized) and orange. When the decolorized crayfish were fed norbixin or bixin, which are components of the orange annatto pigment, norbixin tended to accumulate as orange in the exoskeleton more than bixin based on the apparent body color change, color extraction from images, and thin-layer chromatography. These findings are expected to be useful for science and nutrition education, supporting the development of the students’ awareness and understanding of crayfish as a food resource.
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National versus Local Climatic Variability and Implications for Communities in Protected Areas: The Case of Lake Malawi National Park "jointly worked" Reviewed International coauthorship International journal
Dickson M. Mazibuko, Lameck Fiwa, Maskey Sarvesh and Hiromu Okazawa
International Journal of Environmental and Rural Development 14 ( 1 ) 170 - 176 2023.06
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation
Understanding the rainfall dynamics of a nation/region is key to decision-making, especially regarding agriculture within protected areas. This study focused on the area of Cape Maclear and the adjacent villages located within the Lake Malawi National Park (LMNP). By gaining insight into how communities whose agricultural activities interact with protected areas operate, we can gain insight into the long-term sustainability of the LMNP. This study aimed to assess the historical rainfall dynamics for Cape Maclear using 35-year annual rainfall and temperature data. Rainfall trends were established and compared with recorded events. The results indicated that Cape Maclear rainfall trends resonate with reported national drought events, though with variations. This provides a proxy possibility of making localized predictions of such events. Analysis of the return period shows annual rainfall of between 500900 mm occurs every 2-3 years, indicating no significant shifts from what has been observed in the past. Due to the sensitivity and fragility of the LMNP ecosystem, there is a need to design local solutions for the communities living within the park to enable them to better prepare for future climatic shocks, especially rainfall inadequacies.
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Verifying Optimum Flying Conditions for UAV Photogrammetry in Assessing Hydro-structural Facilities "jointly worked" Reviewed International journal
Sarvesh Maskey, Hiyori Iseki, Kiseki Kurashina, Ke Zhang and Hiromu Okazawa
International Journal of Environmental and Rural Development 14 ( 1 ) 119 - 125 2023.06
Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation
Monitoring hydro-structural infrastructure is becoming an important and challenging issue. In Japan, there are an increasing number of aging hydro-structural facilities, which need to be inspected to guarantee their strength and durability function. Unmanned Aerial Vehicle (UAV) photogrammetric images have been used in the detection of structural deterioration of various infrastructure. However, there is a challenge in determining the optimum flying conditions (altitude, angle of camera, and flying patterns) of UAVs for obtaining images. The designs, shapes, and sizes of hydro-structural facilities also pose a challenge for obtaining ideal images. In this study, verification of various flying conditions for producing images and 3D models was proposed for water gates and open surface water channels. Additionally, an evaluation method for the images and 3D models was suggested. In this study, UAV was used for visual inspection and obtaining the image of the water gate and open surface water channel at the Tone diversion gate in Saitama, Japan. Various geometric patterns were pasted on the surface and walls of the structures to evaluate the detection of the patterns with the images taken from UAVs at different flying conditions. The obtained ortho-mosaic images were processed by a PIX4D mapper to obtain a point cloud-based 3D model and were compared with the actual measurements of the patterns. The results of the study suggested that altitude and camera angles affected the quality of images significantly. Cameras at lower angles provided better images, although cameras at high altitudes with wider angles also demonstrated a high degree of efficiency. The circular flying pattern generated satisfactory results, where flyovers were conducted multiple times while changing altitudes and angles of the camera. Additionally, this study proposes a method named “leveling” for the evaluation of images and 3D models.
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National versus Local Climatic Variability and Implications for Communities in Protected Areas: The Case of Lake Malawi National Park "jointly worked" Reviewed International coauthorship
Dickson M. Mazibuko, Lameck Fiwa, Maskey Sarvesh and Hiromu Okazawa
International Journal of Environmental and Rural Development 14 ( 1 ) 170 - 176 2023.06
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation (ERECON)
Understanding the rainfall dynamics of a nation/region is key to decision-making, especially regarding agriculture within protected areas. This study centers around Cape Maclear and the adjacent villages located within the Lake Malawi National Park (LMNP). By gaining insight into how communities whose agricultural activities interact with protected areas operate, we can determine the long-term viability of the LMNP's sustainability. This study aimed to assess the historical rainfall dynamics for Cape Maclear using 35-year annual rainfall and temperature data. Rainfall trends were established and compared with recorded events. It has been found that Cape Maclear rainfall trends resonate with reported national drought events, though with variations. This provides a proxy possibility of making localized predictions of such events. Analysis of the return period shows annual rainfall of between 500900 mm occurs every 2-3 years, indicating no significant shifts from what has been observed in the past. Due to the sensitivity and fragility of the LMNP ecosystem, there is a need to design local solutions for the communities living within the park to enable them to better prepare for future climatic shocks, especially rainfall inadequacies.
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Verifying Optimum Flying Conditions for UAV Photogrammetry in Assessing Hydro-structural Facilities
MASKEY SARVESH, ISEKI HIYORI, KURASHINA KISEKI, ZHANG KE, OKAZAWA HIROMU
International Journal of Environmental and Rural Development 14 ( 1 ) 119 - 125 2023
Language：English Publisher：Institute of Environmental Rehabilitation and Conservation, Research Center
<p>Monitoring hydro-structural infrastructure is becoming an important and challenging issue. In Japan, there are an increasing number of aging hydro-structural facilities, which need to be inspected to guarantee their strength and durability function. Unmanned Aerial Vehicle (UAV) photogrammetric images have been used in the detection of structural deterioration of various infrastructure. However, there is a challenge in determining the optimum flying conditions (altitude, angle of camera, and flying patterns) of UAVs for obtaining images. The designs, shapes, and sizes of hydro-structural facilities also pose a challenge for obtaining ideal images. In this study, verification of various flying conditions for producing images and 3D models was proposed for water gates and open surface water channels. Additionally, an evaluation method for the images and 3D models was suggested. In this study, UAV was used for visual inspection and obtaining the image of the water gate and open surface water channel at the Tone diversion gate in Saitama, Japan. Various geometric patterns were pasted on the surface and walls of the structures to evaluate the detection of the patterns with the images taken from UAVs at different flying conditions. The obtained ortho-mosaic images were processed by a PIX4D mapper to obtain a point cloud-based 3D model and were compared with the actual measurements of the patterns. The results of the study suggested that altitude and camera angles affected the quality of images significantly. Cameras at lower angles provided better images, although cameras at high altitudes with wider angles also demonstrated a high degree of efficiency. The circular flying pattern generated satisfactory results, where flyovers were conducted multiple times while changing altitudes and angles of the camera. Additionally, this study proposes a method named "leveling" for the evaluation of images and 3D models.</p>
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Impact Evaluation of Climate Change on Disaster Risk of Forested Watershed Rivers in Snowy Regions using SWAT+
KIKUCHI SHOTARO, MASKEY SARVESH, OKAZAWA HIROMU, AZAEL MAY CUEVAS SERGIO, OBA MAKOTO, NAKAMURA SHOGO, HAYASHI SEIJI
International Journal of Environmental and Rural Development 14 ( 2 ) 100 - 106 2023
Language：English Publisher：Institute of Environmental Rehabilitation and Conservation, Research Center
<p>In this study, we analyzed the reduction in snowfall and snowmelt under climate change scenarios in a cold snowy region. Also, we clarified the causal relationship between deforestation and disaster risk in watershed management in Mishima Town, Fukushima Prefecture. We used SWAT+ to conduct simulations; the SWAT+ model of Mishima town was built in a previous study, and its reproducibility was verified by NSE and RMSE by correcting parameters and using auto-calibration. The latest set of models from the CMIP6, also used in the 6th Impact Assessment Report of the IPCC and statistically downscaled scenarios in Japan developed by the Center for Climate Change Adaptation, National Institute for Environmental Studies, was adapted to simulate climate change scenarios. The Emission Scenarios are based on RCP8.5, which has been used in future climate change discussions (i.e., the assumption that greenhouse gases will continue to increase without any global warming countermeasures). We simulated the end of the 21<sup>st</sup> century situation. As the result of the simulation, the RCP8.5 scenario showed a significant decrease in snowfall and snowmelt, with only one day of snowfall of RCP8.5 from January to March. The potential for early spring snowmelt water availability of RCP8.5 at the end of the 21st century could have been much higher. Additionally, we conducted a simulation of deforestation. We assumed that 5 % of the forested area became agricultural land due to deforestation. Simulation results indicated that the surface flow under deforestation conditions was 145.1 mm, a 7 % increase over the surface flow of the original forest prior to deforestation (135.1 mm). Heavy and long-lasting rainfall showed no difference in water storage function between the two cases, but 5 % deforestation was shown to increase river discharge at the beginning of a rainfall event.</p>
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Evaluation of the Effect of Alternate Wetting and Drying Irrigation on the Growth of Paddy Rice Plant Height Using a Logistic Model
KURASHINA KISEKI, MASKEY SARVESH, M. MAZIBUKO DICKSON, OKAZAWA HIROMU
International Journal of Environmental and Rural Development 14 ( 2 ) 20 - 26 2023
Language：English Publisher：Institute of Environmental Rehabilitation and Conservation, Research Center
<p>Climate change poses a challenge to irrigation water supply, especially in the case of the continuous flood irrigation method (CF). Alternate wetting and drying irrigation (AWD) is a method of rice cultivation widely used as a mitigation measure for water consumption, without reducing yields. To better promote AWD in areas where water scarcity occurs in the future, it is necessary to quantify the impact of AWD on growth. The objective of this study was to evaluate the impact of AWD on rice growth under AWD irrigation using logistic curves. Subsequent analysis demonstrated that by using AWD, irrigation capacity was reduced by approximately 19 %. Additionally, multiple regression analysis indicated that temperature, sunshine hours, and relative humidity had significant effects on plant growth. A growth model (RMSE = 2.98 cm to 3.82 cm) was generated by applying a logistic curve where the daily mean integrated values of meteorological data as explanatory variables and plant growth as the objective variable. Using the model, it was found that AWD increased the growth rate of the rice plant; however, rice plant growth in the initial period was lower compared to CF.</p>
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Educational Material Research on the Color of Crayfish for Conversion to Edible Resources
HIGUCHI SAKI, ONO HONAMI, HONDA HIROAKI, MASKEY SARVESH, KUROSAWA AKIRA, SUZUKI TOSHIHIRO, TAKAHASHI NOBUYUKI, OKAZAWA HIROMU, TAKEDA KOUJI
International Journal of Environmental and Rural Development 14 ( 1 ) 98 - 105 2023
Language：English Publisher：Institute of Environmental Rehabilitation and Conservation, Research Center
<p>The crayfish (<i>Procambarus clarkii</i>) is an invasive alien species consumed as a food source worldwide. However, there is an extremely low demand for it as a food resource in Japan, and it is typically targeted for extermination. One reason for the lack of progress in considering crayfish a sustainable food resource is limited education on the issue during secondary education programs. It is well known that astaxanthin is the pigment responsible for the body color of common red crayfish and crustaceans such as shrimp and crabs. At the same time, while there are ample study materials on plant pigments in the science education curriculum in junior high and high schools in Japan, there are no such materials to our knowledge that focus on animal pigments. Therefore, this research sought to develop teaching materials to deepen understanding of color as a food component of crayfish through an experiment involving extracting and separating their pigments. Using pigments extracted from red crayfish exoskeletons, we developed experimental teaching materials to observe astaxanthin by employing thin-layer chromatography and high-performance liquid chromatography. In addition, an experiment was conducted to observe the effect of different foods on crayfish body color. For the experiment, food was developed to make crayfish bodies white (decolorized) and orange. When the decolorized crayfish were fed norbixin or bixin, which are components of the orange annatto pigment, norbixin tended to accumulate as orange in the exoskeleton more than bixin based on the apparent body color change, color extraction from images, and thin-layer chromatography. These findings are expected to be useful for science and nutrition education, supporting the development of the students’ awareness and understanding of crayfish as a food resource.</p>
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Comparison of Crop Surface Models and 3D Point Clouds by UAV Imagery on Estimating Plant Height and Biomass Volume of Pasture Grass Reviewed International journal
ZHANG KE, SEKIYAMA AYAKO, OKAZAWA HIROMU, YAMAZAKI YURI, HAYASHI KIICHIRO, TSUJI OSAMU, AKIMOTO MASAHIRO
International Journal of Environmental and Rural Development 13 ( 2 ) 137 - 143 2022.12
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation, Research Center
<p>Plant biomass is considered an important parameter for crop management and yield estimation, especially for grassland. Aerial photogrammetric techniques have been used for vegetation data gathering of the areas of dense vegetation fields with high research interest. Recent advances in computer vision include structure from motion and multi-view stereopsis (SfM-MVS) techniques, which can derive 3D data such as digital surface models (DSMs) and orthomosaic from overlapping photography taken from multiple angles. The difference between the DSMs of a planted field and the digital terrain model (DTM) has been referred to crop surface model (CSM). Ever since SfM-MVS has been adopted to derive plant height (PH) and above-ground biomass using CSMs at 2013, this method has become the most explored and verified approach to simulate the structure of crops all over the world. However, the complexity of crop structure is thought to be not well represented in DSMs because the DSMs have only one Z value at each 2D pixel. Besides, lacking a DTM representing the bare ground is another problem when adopting the CSM method. On the other hand, the 3D point cloud where DSMs are derived from UAV may provide the structure information in a faster and more detailed way. This research tested the capability of 3D point cloud in estimating plant height and biomass volume of pasture grass, and compared the results with CSMs. UAV photography were conducted at the experimental field of Obihiro University of Agriculture and veterinary Medicine, Hokkaido, Japan, 2019. The biomass volume estimated by DSM and point cloud have no significant difference, showing that DSM and point cloud have the same performance at estimating biomass volume of grass. In the case that only the simple value data is required, the point cloud data is recommended.</p>
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Estimation of Long-term River Discharge in Forested Watershed in Snowy Region by SWAT "jointly worked" Reviewed International journal
Shotaro Kikuchi, Hiromu Okazawa, Sarvesh Maskey, Sergio Azael May Cuevas, Makoto Oba, Shogo Nakamura and Seiji Hayashi
International Journal of Environmental and Rural Development 13 ( 2 ) 105 - 112 2022.12
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation (ERECON)
Utilizing a hydrological model for analyzing the hydrological cycle throughout a river basin is an effective method to assess the impacts of climate change on water resource management, flood control, and agriculture. Although there are various hydrological models developed, in this study, Soil and Water Assessment Tool plus (SWAT+) is used as it is widely used and predicts the impacts of land use management in watershed management. SWAT+ is a complex quasi−physically based water quality model relying on numerous input files and parameters, thus this poses a great challenge when attempting to set up the model manually, and there is a lack of information regarding the validation of SWAT+'s of performance for snow accumulation and melting processes. The objective of this study is to estimate long-term streamflow in forested watershed in snowy region using SWAT+, and to verify the accuracy of the estimation and to confirm the improvement of the accuracy by adjusting parameters. In order to improve the accuracy of simulation, “the saturated hydraulic conductivity of soil layer” and “the available water capacity of soil layer” were adjusted for parameter of soil moisture content, moreover, we adjusted parameter of temperature of “snowfall” and “snowmelt”. Finally, “the time of lateral flow travel” which is difficult to measure was calibrated using the auto-calibration of SWAT+. As the results, it was difficult to achieve high accuracy in predicting river discharge with the default parameters of SWAT+, but some months (May-Oct) could be accurately predicted after adjusting parameters using measured data and conducting the auto-calibration. On the other hand, simulations during snowfall and snowmelt term (Dec-Mar) were less accurate and need to set more detailed conditions.
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Evaluation of Sediment Trapping Capacity by Geotextile for Erosion Control "jointly worked" Reviewed International journal
Sarvesh Maskey, Takanori Kaneko, Hiromu Okazawa, Antonio Perez Fuentes, Sachiko Watanabe, Kazuhiro Tazaki and Takahiro Sasaki
International Journal of Environmental and Rural Development 13 ( 2 ) 99 - 104 2022.12
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation (ERECON)
Heavy precipitation events induce sediment transport resulting in soil loss, aggravating erosion. Geotextile for erosion control, offers environmentally friendly benefits and have lower costs than other physical structures. Recently, there has been interest in high performance and multifunctional geotextiles. In this study, evaluation was made to investigate the capacity of geotextile in sediment trapping. A runoff experiment was conducted, using a runoff plot using two types of geotextiles, having dimensions of 100 and 10 cm length and breadth respectively. Slope for the runoff plot was created at 0.859 degrees. Four treatments, for each geotextile were made. The treatments were, 1) no folds, 2) folds for 25 cm of the runoff plot, 3) folds for 50 cm of runoff plot, 4) folds for 100 cm of the runoff plot. Muddy water suspension having Suspended Solid (SS) of 25000 mg/L was discharged on the treatments. SS of runoff and infiltered suspension were analyzed. According to the results, both geotextiles were effective in sediment trapping. For Sample A, SS decreased by 88.1%, 97.16%, 99.14% and 99.15% in no folds, 25 cm fold, 50 cm fold and 100 cm fold treatment respectively from the initial SS of the muddy water suspension. Whereas, for Sample B, SS decreased by 87.3%, 91.87%, 98.74% and 98.34% in no folds, 25 cm fold, 50 cm fold and 100 cm fold treatments respectively. Additionally, SS significantly decreased in folded treatments for both geotextiles. Accordingly, it was established that geotextile can function for erosion controlling with increase in folds. However, further research is required to understand the intensity of discharge on geotextiles for sediment trapping capacity for future applications.
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Evaluating Ion Exchange Capacity of Molten Slag for Hydroponic System "jointly worked" Reviewed International journal
13 ( 1 ) 143 - 146 2022.06
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Environmental Rehabilitation and Conservation
Hydroponic farming promotes high-efficiency water, fertilizers, and high productivity under a controlled environment. However, the use of this system needs consistent application of fertilizers, increasing the cost of operations. Molten Slag (MS), a waste from the Municipal Solid Waste Incineration has essential nutrients that can be used as fertilizer. The objective of this study was to clarify the releasing process of nutrients by molten slag to be applied as a substrate in hydroponic system. For this, anion and cation contents of three varieties of Molten Slag (MS1, MS2, MS3) were determined in the laboratory by a shaking method. The nutrient content, P2O5, K2O, MgO and CaO were in MS1, MS3 and MS2. The quantification ion released was performed at 1, 6, 12 and 24 hours. It was observed that MS3 had performed the best condition in the releasing process of K+, Mg+, SO42- and Cl-. Although MS1 had higher nutrient content, MS3 released higher contents of those minerals among the samples. According to the result of this study, it was confirmed that MS3 has a high potential for hydroponic farming.
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Relationship between NDVI and Canopy Cover Sensed by Small UAV under Different Ground Resolution "jointly worked" International journal
Ke Zhang, Hiromu Okazawa, Yuri Yamazaki, Kiichiro Hayashi, Osamu Tsuji
International Journal of Environmental and Rural Development 12 ( 2 ) 122 - 128 2021.12
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：特定非営利活動法人環境修復保全機構 研究センター
In this study, small UAVs took RGB and multispectral images of the experimental peanuts field in Hokkaido. Orthomosaic and reflectance map of the field were constructed using the UAV imagery and then were obtained CC and NDVI values with GIS software. CC was calculated as the green canopy area ratio, extracted from the orthomosaic using a GIS supervised classification tool. CC was compared with NDVI values under various resolutions of 0.50 m, 1.0 m, 2.5 m, 5.0 m, and 10 m. The NDVI showed a highly correlated linear relationship with CC under each ground resolution from 0.10 m to 10 m (R2 led a range of 0.88** to 0.94**). The shapes of NDVI and CC’s regression equations closely resembled each other, with the slopes of 1.06 to 1.11 and the intercepts of 0.247 to 0.250, respectively. From the result of ANCOVA, the UAV imagery resolution has no significant impact on NDVI and CC’s relationship. Although more irrelevant factors, such as soil and mulching seat, got included within one pixel of the images, the regression equations stayed the same with the increased ground resolution.
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Applicability of Tank Model in Mid-Sized Catchments in Eastern Uganda "jointly worked" Reviewed International journal
Emmanuel Okiria, Hiromu Okazawa, Yuri Yamazaki, Yukimitsu Kobayashi and Shinji Suzuki
International Journal of Environmental and Rural Development 11 ( 2 ) 32 - 38 2020.12
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：特定非営利活動法人環境修復保全機構 研究センター
ウガンダ東部の山間部にある農林地流域河川を対象に，直列4段のタンクモデルによる河川流量のシミュレーションを行った。そして，流量予測の精度は高く，河川流量を表面流と基底流の2種に分けることができ，河川水質の形成機構に寄与する重要なモデルであることを示した。
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Examination of Optimal Search Method of Unknown Parameters in Tank Model by Monte Carlo Method "jointly worked" Reviewed International journal
Koji Miwa, Kosuke Mukae, Hiromu Okazawa, Tadao Yamamoto, Takashi Inoue and Emmauel Okiria
International Journal of Environmental and Rural Development 11 ( 1 ) 1 - 7 2020.06
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：特定非営利活動法人環境修復保全機構 研究センター
北海道南西部の森林，草地を主体とする流域において，TANKMODELの適用を試みた。特に，TANKMODELによる流出解析に必要となる流出孔の係数などを決定する計算回数について検討した。
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Identifying the Minimum Number of Observed Rainfall Events Required for Optimal TOPMODEL Parameters in Mid-sized Equatorial Catchments "jointly worked" Reviewed International journal
Emmanuel Okiria, Hiromu Okazawa, Yuri Yamazaki, Yukimitsu Kobayashi and Shinji Suzuki
International Journal of Environmental and Rural Development 10 ( 2 ) 113 - 119 2019.12
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：International Society of Environmental and Rural Development
ウガンダ国東部の山間地流域において，水文流出モデルであるTOPMODELのパラメータ設定に必要な降雨イベント数を検討した。パラメータの数値決定に降雨イベントのデータ数が関係することを示した。
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Accuracy Verification of UAV-SfM Survey of Terrace Paddy Fields in a Hilly and Mountainous Area "jointly worked" Reviewed
Yuri Yamazaki, Hiromu Okazawa, Ayako Sekiyama and Tomonori Fujikawa
International Journal of Environmental and Rural Development 10 ( 1 ) 151 - 156 2019.06
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：nternational Society of Environmental and Rural Development
静岡県菊川市の千框棚田において，傾斜地に展開する水田を対象にUAV測量の精度を検証した。UAV測量では地上の既知点であるGCPを配置して，位置情報の補正を行う必要がある。一方，GCPの設置条件と測量精度について論じた報告は少ない。ここでは，GCPの設置数と配置がUAV測量の精度に及ぼす影響を検証した。
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GIS-based Analysis for the Energy Potential and Social Feasibility of Small-Scale Run-Off-River Hydropower in Yahagi River, Japan "jointly worked" Reviewed International journal
Yuri Yamazaki, Kiichiro Hayashi, Nobuko Kawaguchi, Hiromu Okazawa and Ferdinando Villa
International Journal of Environmental and Rural Development 10 ( 2 ) 133 - 140 2019.06
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：International Society of Environmental and Rural Development
愛知県，長野県を流域に持つ矢作川流域において，小水力発電のポテンシャル推計を行った。GISによる地形，河道，人口，配電施設，保護区などの複数データによる解析から，効率的に発電を行い導電できる発電適地の選定をする手法を確立した。
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Issues of Disaster Recovery Management and Application of GIS and UAV for Resilience in Agricultural Land and Infrastructure "jointly worked" Reviewed
Koji Miwa, Ayako Sekiyama, Toru Nakajima, Takahiko Kubodera, Chikahiro Egami and Hiromu Okazawa
International Journal of Environmental and Rural Development 9 ( 2 ) 114 - 121 2018.12
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：International Society of Environmental and Rural Development
熊本地震によって被災した農地の復旧対策には，UAVやGISによる管理手法が有効である。ここでは，行政を対象に，GISによる農地管理手法の有効性とUAVによる新たな管理手法の導入について地方自治体にアンケートを実施し，これらの導入に対する市来調査を行い問題点を明らかにした。
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Application of TOPMODELs for Assessment of Ecosystem Services: Regulating Service in Agricultural and Forest Watershed "jointly worked" Reviewed International journal
Kosuke Mukae, Koji Miwa, Hiromu Okazawa, Tadao Yamamoto, Takashi Inoue
International Journal of Environmental and Rural Development 9 ( 1 ) 43 - 50 2018.06
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：International Society of Environmental and Rural Development
生態系サービスのひとつである調整サービスの定性的評価を目的として，北海道の森林流域と農業流域を対象に洪水予測で用いられるTOPMODELの適用を試みた。TOPMODELは準分布型モデルでり，他軌道においても適用性が高いことが示された。また，５つのパラメータを用いて，調整サービスの違いを示すことができた。
DOI： https://doi.org/10.32115/ijerd.9.1_43
Other Link： http://iserd.net/ijerd91/IJERD9-1-8.pdf