남한의 수평면 일사량 추정을 위한 일조시간 경험식의 비교

( Amrita Das ),박진기 ( Jin-ki Park ),박종화 ( Jong-hwa Park ) 한국농공학회 2014 한국농공학회 학술대회초록집 Vol.2014 No.-

The exhaustion of current fossil fuel resources and increasing risk of global warming and have motivated the global scientific community to search and develop other non-conventional energy sources like solar energy. Besides designing of solar energy system, accurate insolation data is also a key component for many biological study especially in case of different agricultural models. But solar radiation measuring stations are not easily available due to financial and technical limitations and this insufficient number affects the spatial resolution whenever an attempt is made to construct available radiation map using any interpolation method. The number of stations measuring solar radiation is minor if compared to the number of stations recording other climatic parameters like sunshine hours. There are several models in literature for estimating incoming solar radiation using the sunshine fraction. Seventeen of such models among which 6 are linear and 11 non-linear, has been chosen for studying and estimating solar radiation on a horizontal surface over South Korea. At first physically questionable data are filtered using box plot model. The data set is divided according to their S (Sunshine ratio) value into smaller band, each having a width of 0.01. The general statistics of K (clearness index) values for all S bands is then calculated and the upper and lower limits of K for each band are centered on the median of corresponding band. It excludes aberrant data. Daily radiation data from 2001 to 2012 over 22 stations is used to estimate the model parameters and data from 2013 is used to evaluate the model performance. Based on statistical error tests, Model 8 (K = P3×S2+P4×S+P5; P3 =0.812-1.0102×SA; SA is annual mean sunshine ratio) and Model 16 (K = P14+P15×SP16) are found to be most accurate than others for Korea. The MBE and RMSE for the above mentioned models are 0.99 MJ/m²/day; 1.03 MJ/m²/day and 2.21 MJ/m²/day; 2.19 MJ/m²/day respectively. The better performance of non-linear model rather than those guided by Angstrom equation established the fact that the relationship between sunshine duration and clearness index does not follow a straight line. With Model 8 solar radiation over 81 station measuring sunshine duration is computed and used as an input for spatial interpolation. Monthly solar radiation map is constructed using Ordinary Kriging method and evaluated by the observed radiation data over 22 stations in 2013. The cross validation results show well agreement between observed and predicted data with an R value of 0.92 and RMSE 1.64 MJ/m²/day.

Characterization of Bacillus anthracis proteases through protein-protein interaction: an in silico study of anthrax pathogenicity

Amrita Banerjee,Pradeep Kumar Das Mohapatra,Shilpee Pal,Keshab Chandra Mondal,Bikash Ranjan Pati,Arnab Sen,Tanmay Paul 셀메드 세포교정의약학회 2014 TANG Vol.4 No.1

Anthrax is the deadly disease for human being caused by Bacillus anthracis. Instantaneous research work on the mode of infection of the organism revealed that different proteases are involved in different steps of pathogenesis. Present study reports the in silico characterization and the detection of pathogenic proteases involved in anthrax infection through protein-protein interaction. A total of 13 acid, 9 neutral, and 1 alkaline protease of Bacillus anthracis were selected for analysing the physicochemical parameter, the protein superfamily and family search, multiple sequence alignment, phylogenetic tree construction, protein-protein interactions and motif finding. Among the 13 acid proteases, 10 were found as extracellular enzymes that interact with immune inhibitor A (InhA) and help the organism to cross the blood brain barrier during the process of infection. Multiple sequence alignment of above acid proteases revealed the position 368, 489, and 498-contained 100% conserved amino acids which could be used to deactivate the protease. Among the groups analyzed, only acid protease were found to interact with InhA, which indicated that metalloproteases of acid protease group have the capability to develop pathogenesis during B. anthracis infection. Deactivation of conserved amino acid position of germination protease can stop the sporulation and germination of B anthracis cell. The detailed interaction study of neutral and alkaline proteases could also be helpful to design the interaction network for the better understanding of anthrax disease.

Cofinite Graphs and Groupoids and their Profinite Completions

Acharyya, Amrita,Corson, Jon M.,Das, Bikash Department of Mathematics 2018 Kyungpook mathematical journal Vol.58 No.2

Cofinite graphs and cofinite groupoids are defined in a unified way extending the notion of cofinite group introduced by Hartley. These objects have in common an underlying structure of a directed graph endowed with a certain type of uniform structure, called a cofinite uniformity. Much of the theory of cofinite directed graphs turns out to be completely analogous to that of cofinite groups. For instance, the completion of a directed graph Γ with respect to a cofinite uniformity is a profinite directed graph and the cofinite structures on Γ determine and distinguish all the profinite directed graphs that contain Γ as a dense sub-directed graph. The completion of the underlying directed graph of a cofinite graph or cofinite groupoid is observed to often admit a natural structure of a profinite graph or profinite groupoid, respectively.

Identification and distribution of aphid vectors spreading Citrus tristeza virus in Darjeeling hills and Dooars of India

Amalendu Ghosh,Amrita Das,Ruben Lepcha,Kaushik Majumdar,V.K. Baranwal 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.3

Darjeeling hills and Dooars of West Bengal (India) are well known for production of mandarin orange and lime. Citrus tristeza virus (CTV) is wide spread in this region. Role of insect vectors in spreading CTV in this region has not been studied so far. Therefore, a study on identification of insect vectors along with their temporal and spatial distributionwas undertaken. Five aphid species were identified fromcitrus orchards of Darjeeling and Dooars viz. Toxoptera citricida, T. aurantii, Aphis gossypii, Myzus persicae and Brachycaudus helichrysi. T. citricida was found predominant in the orchards of lower altitude and was responsible for maximum spread of CTV. T. aurantii was dominant in the citrus orchards at high altitude (N500 m). Incidence of CTV was higher in the orchards where T. citricida was present either alone or with other species. Under caged conditions, T. citricida was more efficient to transmit CTV than the other aphid species. Occurrences of all aphid species were highly influenced by the advent of new flushes.

농업분야 무인항공기 영상 활용 동향: 리뷰 및 제안

박진기(Jin-Ki Park),Amrita Das,박종화(Jong-Hwa Park) 충남대학교 농업과학연구소 2015 농업과학연구 Vol.42 No.3

Unmanned Aerial Vehicle (UAV) has several advantages over conventional remote sensing techniques. They can acquire high-resolution images quickly and repeatedly. And with a comparatively lower flight altitude, they can obtain good quality images even in cloudy weather. In this paper, we discussed the state-of-the-art of the domestic and international use of UAV in agricultural sector as well as assessed its utilization and applicability for agricultural environment in Korea. Association of robotic, computer vision and geomatic technologies have established a new paradigm of low-altitude aerial remote sensing that has now been receiving attention from researchers all over the world. In a field study, it has been found that use of UAV imagery in an agricultural subsidy program can reduce the farmers’ complain and provide objective evidence. UAV high resolution photography can also be helpful in monitoring the disposal zone for animal carcasses. Due to its expeditiousness and accuracy, UAV imagery can be a very useful tool to evaluate the damage in case of an agricultural disaster for both parties insurance companies and the farmers. Also high spatial and temporal resolution in UAV system can increase the prediction accuracy which in turn help to maintain the agricultural supply and demand chain.

A new approach to estimate the spatial distribution of solar radiation using topographic factor and sunshine duration in South Korea

Park, Jin-Ki,Das, Amrita,Park, Jong-Hwa Elsevier 2015 Energy Conversion and Management Vol.101 No.-

<P><B>Abstract</B></P> <P>Solar radiation is one of the important renewable resources, currently scientists are taking their interest in. Accurate solar radiation data is not only required for solar-power management but also is a vital input parameter in different biogeochemical and atmospheric models. But there are inadequate number of stations measuring solar radiation in comparison to stations dedicated for sunshine duration, temperature, humidity etc. Therefore, to overcome this problem, an empirical model is developed to estimate solar radiation from sunshine duration data over South Korea. As more than 50% of the area in Korean peninsula have a complex terrain, a topographical factor is applied to modeled data. Thereafter a map presenting monthly mean variation in incoming solar insolation is constructed using ordinary kriging method. The influence of topographical features like slope and aspect is found to be higher in winter than summer. Solar radiation is highest in May and lowest in December over Korea. Spatial variation of incoming radiation is mainly influenced by topographical and atmospheric features whereas latitudinal gradient is almost insignificant.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Our goal is to create a map of solar radiation using sunshine hours and topography. </LI> <LI> We found the empirical models based on sunshine hours performs significantly well. </LI> <LI> The effect of topography on radiation is more significant in winter than summer. </LI> <LI> Topographical impact is totally opposite in north and south facing terrain. </LI> <LI> Though the extraterrestrial solar radiation flux is highest in June, at ground observed radiation is higher in May. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Percolation bacterial leaching of low-grade chalcopyrite using acidophilic microorganisms

Karanam Srinivasa Rao,Amrita Mishra,Devbrata Pradhan,Gautam Roy Chaudhury,Birendra Kumar Mohapatra,Trupti Das,Lala Bihari Sukla,Barada Kanta Mishra 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.3

Bioleaching studies were carried out in percolation columns using low-grade copper containing rock (granite). The lixiviant consisted of acidified ferric sulfate containing acidophilic microorganisms. The iron oxidizing strain was isolated from Malanjkhand mine water and after adaptation the iron oxidation observed to be 500 mg/L/h. Leaching parameters studied were lixiviant flow rate, particle size and bed height. It was observed that leaching efficiency increased with decrease of particle size and lixiviant flow rate. The precipitation of iron during leaching observed to be low as pH was maintained at 2. Based on the leaching kinetics, a unified rate equation was developed and shown as ra(dp)[−0.61 (F)−0.76 (Hb)0.97.]수식

무인항공 영상의 농작물 모니터링 활용

박진기 ( Jin-ki Park ),김봉섭 ( Bong-seop Kim ),( Amrita Das ),박종화 ( Jong-hwa Park ) 한국농공학회 2014 한국농공학회 학술대회초록집 Vol.2014 No.-

원격탐사를 이용한 농업분야 모니터링은 주로 시계열 위성영상을 활용하여 이루어졌다. 그러나 기존의 MODIS, NOAA AVHRR 등의 저해상도 위성영상은 짧은 주기의 반복적인 촬영이 가능한 반면에 정밀 농작물 모니터링에는 적합하지 않은 단점을 가지고 있다. 반면에 KOMPSAT, QuickBird 등의 고해상도 위성영상은 동일 지역을 주기적으로 모니터링하기에는 적합하지 않은 단점을 가지고 있다. 더욱이 농업분야 모니터링에서 중요한 시기인 6월~8월에는 장마와 태풍 등의 영향으로 좋은 품질의 영상 취득에 어려움을 가지고 있다. 따라서 이러한 한계점을 극복하기 위한 방법으로 소형 무인항공기(UAV; Unmanned Aerial Vehicle)에 의한 주기적인 농작물 모니터링이 좋은 대안으로 부각되고 있다. 최근에는 무인항공기의 발달과 영상처리의 발전으로 5cm 이하의 고해상도 무인항공영상을 언제 어디서나 반복적으로 편리하게 취득할 수 있으며, 고도 80~350m에서 촬영을 실시하기 때문에 흐린 날씨에 상관없이 농작물 모니터링이 가능한 장점을 가지고 있다. 또한, 무인항공영상의 제작에 필요한 절차는 항공영상의 제작과정과 비슷한 절차로 이루어지지만, 촬영허가 절차가 간편하고, 장비를 가동하는데 걸리는 시간은 획기적으로 짧은 장점이 있다. 본 연구에서는 고정익(Fixed Wing) 무인항공기를 이용해 영상을 취득하여 농작물 모니터링에 활용하였다. 연구에서 사용한 SenseFly사의 고정익 무인항공기(eBee)는 일반적인 비행기와 같은 형태로 구성되어 있다. 관측지점의 자동 경로 비행 및 자동 이착륙이 가능하며, 1회 최대 비행시간은 45분으로 200~300장 정도의 영상을 취득할 수 있다. 본 연구에서는 30분 비행에 143장의 영상을 취득하였다. 무인항공기 탑재되어 촬영에 이용된 카메라는 일본 Canon사의 PowerShot ELPH 110HS 모델로 근적외영역, 녹색영역, 청색영역의 3개 밴드로 촬영된다. 농작물 모니터링을 위해 대상작물은 벼, 땅콩, 들깨, 고구마, 고추, 참깨, 콩 7가지를 선정하였으며, 각 농작물에 대하여 식생지수를 추출하였다. 그 결과 각 농작물마다 서로 다른 식생특성이 나타났으며, 식생이 활발할수록 식생지수는 높아짐을 확인할 수 있었다. 무인항공 영상을 이용한 정밀 농작물 모니터링이 주기적으로 이루어져 기초자료가 축적된다면 고해상도 위성영상의 정밀한 작물 분류도 가능할 것으로 판단된다. 또한 원격탐사 자료를 활용하여 작물의 수분상태, 병충해 등의 생육상황 파악에도 유용하게 활용될 수 있을 것으로 판단된다.