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    Computers and Electronics in Agriculture 73 (2010) 4455

    Contents lists available at ScienceDirect

    Computers and Electronics in Agriculture

    j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c o m p a g

    A user-centric approach for information modelling in arable farming

    C.G. Sorensen a,, L. Pesonen b, S. Fountas c, P. Suomi b, D. Bochtis a, P. Bildse a, S.M. Pedersen d

    arhus University, Faculty of Agricultural Sciences, Department of Agricultural Engineering, Research Centre Foulum, Blichers Alle 20, 8830 Tjele, Denmarkb MTT Agrifood Research Finland, Vakolantie 55, 03400 Vihti, Finlandc Center for Research and Technology, Institute of Technology and Management of Agricultural Ecosystems, Technology Park of Thessaly, 1st Industrial Area, GR 385 00, Volos, Greeced Institute of Food and Resource Economics, University of Copenhagen, Rolighedsvej 25, 1958 Frederiksberg C, Denmark

    a r t i c l e i n f o

    Article history:

    Received 21 August 2009Received in revised form 30 March 2010

    Accepted 8 April 2010

    Keywords:Precision agriculture

    Fertilisation

    Core-task analysis

    FMIS

    DFD models

    a b s t r a c t

    Agriculture and farmers face a great challenge in effectively manage information both internally and

    externally in order to improve the economic and operational efficiency of operations, reduce environ-

    mental impact andcomply withvariousdocumentationrequirements.As a partof meeting thischallenge,

    the flow of informationbetweendecisionsprocesses defined as realizinga decision mustbe analyzedand

    modelled as a prerequisite for the subsequent design, construction and implementation of information

    systems.

    This paper defines the actors, their role and communication specifics associated with the various

    decision and control processes in farmers information management. Core-task analysis and core task

    demands from earlier research are utilised as premises for the modelling of information flow from the

    farmers point of view. A user-friendly generic FMIS design reference model is the primary objective for

    the study in which planning, execution and evaluation measures have been incorporated.

    A user-centric approach to model the information flows for targeted field operations is presented. The

    information modelsare centred aroundthe farmeras theprincipaldecisionmakerand involves external

    entities as well as mobile unit entities as the main information producers. This is a detailed approach

    to information modelling that will enable the generation of a Farm Management Information System in

    crop production.

    2010 Elsevier B.V. All rights reserved.

    1. Introduction

    The analysis of decision processes, as well as information mod-

    eling for field operations is not a new approach. Decision-making

    is an important aspect in farm management and has been stud-

    ied by numerous studies (e.g. Anderson et al., 1980; Van Elderen

    and Kroeze, 1994). The reasoning of why there is a need to ana-

    lyze decision-making has been addressed by Gladwin (1989), who

    argued that the benefit is to know and understand why a specific

    group of people acts as they do. This will enable researchers to pro-

    vide the farmers with supporting knowledge and tools as a way to

    enhance decision-making at specific stages of the process. In agri-culture though, farmers, in general, both generate and execute any

    plan made, andtheir decision process associated with the planning

    remains very much implicitand internal(Srensen, 2000) and often

    make decisions based on their intuition and not using formalized

    planning tools. That is contradictory to the industry, where there is

    a long tradition for explicit planning comprising formalised docu-

    ments passed down to the shop floor by the management section

    Corresponding author. Tel.: +45 89991930.

    E-mail address: [email protected](C.G. Sorensen).

    for implementation (Chary, 2006). The efforts aimed at developing

    agricultural planning support mustbe targeted at externalising and

    formalising the farmers planning effort.

    Kay and Edwards (1999) discussed the unique attributes that

    make farm business complex in comparison to the industry, such

    as the biological processes, the fixed supply of land, the small

    size, weather forecast and the perfect competition (Runge, 2006).

    They argued that the systematic analysis of decision-making pro-

    cess would not necessarily lead to perfect decisions, but would

    help a farm manager act in a logical and organized manner when

    confronted with choices. The US North-Central Regional Research

    team in Farm Information Systems (2000) categorized the farm-ers into two groups: information hogs seeking and using large

    amountof informationand seatof thepantswherepersonalintel-

    lect and intuition are the main drivers in decision-making. They

    observed that seat of the pants farmers most likely utilize infor-

    mation in ways not fully understood by researchers or advisors.

    It is perhaps useful to recognize intuition as a complex result of a

    given farmers unique experience and familiarity with his/her farm.

    Much of the information exists as tacit knowledge of the farmer,

    but in order to specify all the elements it is necessary to explic-

    itly specify the detailed information flows for individual planning

    tasks.

    0168-1699/$ see front matter 2010 Elsevier B.V. All rights reserved.

    doi:10.1016/j.compag.2010.04.003

    http://dx.doi.org/10.1016/j.compag.2010.04.003http://dx.doi.org/10.1016/j.compag.2010.04.003http://www.sciencedirect.com/science/journal/01681699http://www.elsevier.com/locate/compagmailto:[email protected]://dx.doi.org/10.1016/j.compag.2010.04.003http://dx.doi.org/10.1016/j.compag.2010.04.003mailto:[email protected]://www.elsevier.com/locate/compaghttp://www.sciencedirect.com/science/journal/01681699http://dx.doi.org/10.1016/j.compag.2010.04.003
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    C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455 45

    With the advent of Precision Agriculture (PA) technologies

    farmers acquire a vast amount of data and they face even big-

    ger problems on how to effectively utilize them to make better

    decisions (Auernhammer, 2001). PA aims to change the focus of

    agricultural production from quantity to quality and sustainability

    ( Jensen et al., 2000). By generic definition, PA refers to agricul-

    tural techniques that increase the number of (correct) decisions

    per unit area of land per unit of time, with associated net benefits

    (McBratney et al., 2005). When practising PA, a farmer manages

    crop production inputs (seed, fertiliser, lime, pesticides, etc.) on

    a site-specific basis to increase profits and crop quality, but also

    to reduce waste and maintain environmental quality. In order to

    make precise decisions in different phases of the farming process,

    the farmer therefore needs to analyse information from different

    vastand dispersedlocatedinformation sources. Managementof the

    information and decision-making is the core issue for the farmer in

    successful PA, not the data acquisition process.

    Fountas et al. (2006) have decomposed the decision-making

    process for farmers using PA into twenty-one decision analysis

    factors. These factors were assembled into a data flow diagram

    describingthe main information processes and flows.The diagrams

    analyzed theinformation flows forfield operations taking a general

    approach to represent the transformation from gathered data into

    informationandthendecisions.Nash etal. (2009) modeledallrangeof data flows covering the broad spectrum of PA practices into one

    very large diagram showing the interrelations, while also including

    the modeled data-streams for specific PA practices, such as man-

    agement zones, yield mapping or exploitation of remote sensing

    data.

    The required information modelling can be fulfilled through

    concentrated efforts aimed at extracting domain knowledge and

    deriving information flows at various planning and process lev-

    els. This effort demands considerable research and development,

    which is the case in terms of incorporating user preferences and

    requirements. The tendency to use a more user-centric approach

    in developing new technologies has gained considerable appeal

    (e.g. Akao and Mazur, 2003; Norros, 2004). The core-task analysis

    (CTA) is a user-centric methodology, which was initially devel-oped in Governmental Technical Research Centre of Finland (VTT:

    Valtion Teknillinen Tutkimuskeskus) (Norros, 2004). It is a func-

    tional modelling technique that informs system modellers of the

    aims, intrinsic constraints and user practices in the work under

    study A user-centric approach assumes that the users ideas and

    requirements reactions concerning the specific characteristics of

    the designed technology are integrated in the subsequent design.

    When end-users and other actors in the value chain are involved

    into the design and development process from its early stage, the

    system becomes more realistic to realise and build in real world,

    andit readily meets most of theuser requirements. Since the adop-

    tion of Decision Support Systems (DSS) and Farm Management

    Information Systems (FMIS) within PA has been disappointingly

    low (Rosskopf and Wagner, 2003; McBratney et al., 2005; Parker,2005), this kind of user-centric development method is expected

    to improve the acceptance of the new technology in the markets

    and among end-users. This leads to smaller risk associated with

    introducing new FMIS in the farm business domain (Norros et al.,

    2009), which was communicated in a research project, InfoXT1

    user-centric mobile information management in automated plant

    production running from 2006 to 2008 in Scandinavia (Pesonen

    et al., 2008). Here,the applicability of using a user-centric approach

    to develop an information system for mobile work units was indi-

    cated.

    1

    www.mtt.fi.infoxt.

    The aim of this paper is to define the actors, their role and

    communication specifics associated with the various decision and

    control processes in farmers information management. The core-

    task analysis involving farmer interviews and derived Core-Task

    demands is the basic framework for the pursued approach. A user-

    friendly generic FMIS design reference model is the primary target

    for the study where both planning, execution and evaluation mea-

    sures are incorporated. The generic design is intended to support

    and guide the actual implementation of a specific FMIS in terms

    of capability, invoking of information and communication tech-

    nologies, etc. The design reference model is developed in the early

    phases of system design and the detailed decomposition and com-

    ponent construction can be derived from this model.

    This study was part of an on-going EU research project

    FutureFarm.2 FutureFarm has defined aims at meeting the chal-

    lenges of the farm of tomorrow by integrating Farm Management

    Information Systems (FMIS) to support real-time management

    decisions and compliance to standards.

    2. Farm management and field operations

    The agricultural production processes within arable farming

    involve transformation processes that are realised by biologicalprocesses (e.g. crop biomass growth) taking place in the course of

    the growing season. The processes are regarded as an autonomous

    system, which is basically independent of decisions made by the

    farmer. In contrast to this, the intervention realised by labour and

    machinery during the plant growing process is dependent on deci-

    sions made by the farmer and termed an operation. An formaldefinition of an operation is given by Van Elderen (1977), who

    statesthat an operationis a technicalcoherent combination of treat-ments by which at a certain time a characteristic change of conditionof an object (a field, a building, an equipment, a crop) is observed,realised or prevented. This definition extends operations beyondthose for crop production to supporting enterprise functions like

    maintenance, repairs, etc. An operation is generallyseen as the link

    between some resources (e.g. labour and machinery), some mate-

    rials processed, and some material produced (e.g. harvested crops,

    repaired machine, etc.).

    The decomposition of information processes attributed to the

    planning and execution of field operations is based on the manage-

    ment functions ranging from strategical to operational planning,

    execution control and evaluation, and a number of underlying pro-

    cesses and sub-processes. All planning levels have to be included

    in a generic FMIS as it is necessary to know what kind of infor-

    mation the system has to be able to handle. Farmers cannot have

    separate systems for each managementlevel. All levelsutilise/need

    data/information produced in the other levels. The integration of

    all planning levels is pivotal to the usefulness of the FMIS. Fig. 1

    outlines the basic management processes which are identified

    within theagricultural plant production cycle forboth manned and

    unmanned machinery items.

    Plan generation and execution must be linked in a system

    monitoring effects of actions, unexpected events and any new

    information that can attribute to a validation, a refinement, or a

    reconsideration of the plan. Plans must be presented condition-

    ally, so that supplementary knowledge from observations, farm

    databases, sensors, etc.,can be incorporated in orderto reviseplans.

    It should be noted, that although that the concept of farm

    databases is an important issue in the modelling of a FMIS, it is not

    within the scope of the paper. The pursued concept, in principle,

    does not make any difference between information in a database

    2

    www.futurefarm.eu .

    http://www.mtt.fi.infoxt/http://www.futurefarm.eu/http://www.futurefarm.eu/http://www.mtt.fi.infoxt/
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    46 C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455

    Fig. 1. Information and planning activities in agricultural operations management with the identification of the revised task formulation to be invoked in the case of

    autonomous vehicles (adapted from Goense and Hofstee, 1994).

    and the information present in the memory of the farmer. It is

    all available information which can be drawn upon and where

    the distribution of the available information between a physical

    database and the memory of the farmer depends on the degree

    of automated decision-making and as such, the degree of explicitly

    formulated information storage.

    3. Methodology

    The information modelling used in this study utilises the user-

    centric research and designing method, the so-called core-task

    analysis (CTA) method, developed in earlier work carried out in

    Scandinavia (Norros, 2004; Nurkka et al. 2007; Pesonen et al.,

    2008). The method employs ISO 13407 standard (ISO 13407, 1999,Human-centred design processes for interactive systems) aiming atgood systems usability by integrating the end-users to the devel-

    opment process from the beginning. The method consists of seven

    phases (Fig. 2) and it is based on core-task analysis (CTA) of farm

    work. The phases of the method are shown in Fig. 2. CTA is a func-

    tional modelling technique that informs system modellers of the

    aims, intrinsic constraints and user practices in the work under

    study. In the method, it is seen that a result-oriented and meaning-

    ful human-environment interaction is a functionalsystem in which

    the environment provides possibilities (affordances) that human

    actors learn to grasp (prehensilities) (Norros and Savioja, 2006).

    Fig. 2. Seven phasesof thecore-task analysis-based userdemandmodelling system

    (Nurkka et al., 2007).

    Affordances and prehensilities of a particular domain and the aimed

    results constitutethe core-task of that activity.The modellingof thecore-task gives the potential for action in the particular context.The CTA method was developed further and applied in a study that

    aimed to improve information management of high quality cereal

    (malt barley) production (Nurkka et al. 2007). The CTA method

    attained the form where it consists of two parts: research and

    design (Fig. 2).

    The methodology employed in this study, utilises basic work of

    phases 14 of Fig. 2 for targeted farm operations. Science-based

    modelling of a core task was the first phase of the modelling

    relying on expert knowledge of the use of PA practices within

    crop production. Scientific and professional literature, four expert

    interviews and several workshops with the research group pro-vided the data for the modelling. The aim was to indicate the

    content of the relevant and important information regarding the

    decision-making for the targeted field operations under study.This

    information comprised the information used in planning, execu-

    tion and evaluation, together with the core-task demands. The

    core-task demands define how farmers use skills, knowledge and

    collaboration to control dynamicity, uncertainty and complexity

    of crop production work (Nurkka and Norros cit. Pesonen et al.,2008).

    Analysis of orientation (phase 2) was carried out in Finland

    among 11 interviewed producers to identify those farmers who are

    keen on constantly improving field processes to gain good product

    quality and environmental friendly methods, in other words the

    farmers who possess PA orientation (Nurkka et al., 2007).In the third phase, as part of the practice-based modelling, indi-

    vidual farmer interviews were carried out in a half-day workshop

    organized at four farms in Finland (Nurkka et al., 2007) and at five

    farms in Sweden (Olsson and Rydberg, 2008). During the work-

    shops, the farmerspracticeswere simulatedby inviting the farmers

    to draw their own conceptual models of the growing process based

    on theexperiences of thepreceding farming period. The modelwas

    toportraythe actions they made andtools they used duringthe pro-

    cess. They were encouraged tomake as many comments as possible

    on the content, origin and type of the information they used and

    how they used it in different phases of the process. The aim of this

    phase was to understand what the obstacles are in the use of the

    systems to support PA and what the actual needs for the farmers

    are regarding FMIS.

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    Fig. 3. Analysis and modelling approach.

    In the phase 4 (Integrated Information Modelling), all the data

    from the preceding modelling were applied. The work was done

    in workshops comprising agronomists, agrotechnology scientists

    and farmers. This phase was creative and iterative combiningresearch and practice, and the first drafts of information models

    were designed as a result. Ideas about the possible technological

    advances were taken into account. The modelling was an itera-

    tive process having current farm technology as a foundation, but

    also looking for the possibilities to utilise efficientlyadvanced tech-

    nologies like ISOBUS and wireless communication. However, at all

    times, the information flow models were created and revised from

    the farmers (end-users) point of view.

    A detailed structuring and formalisation of physical entities

    and the information, which surrounds the planning and control

    of efficient mobile working units is a decisive prerequisite for the

    development of comprehensive and effective ICT-system for taskmanagement on the farm. The basic idea was to capture the high-

    level planning and control activities, which take place in a targeted

    production section, and represent explicitlythe domain knowledge

    in terms of domain entities and their relationships, (Fig. 3), and

    based on the basic CTA approach and work presented above

    The actors are defined as information operatives or as the enti-

    ties which are capable of storing or processing information by

    way of the explicitly defined decision processes. The defined actors

    Table 1

    Planning levels and aggregated information flows in field operations.

    Planning level Information required Information provided

    Strategic planning or design of the production system : Design

    of production system for a period of 15 years or 2 or morecropping cyclesspecifically the labour/machinery system

    and selection of types of crops

    Possible production levels and price developments Number and dimensions of machines

    Operations demands Machine capacityPossible work methods Labour requirement

    Available machinery on the market Crops selected

    Costs

    Tactical planning: Setting up a production plan for a periodof 12 years or 12 cropping cycles.

    Strategic plan Crop plan

    Availability of land, buildings and equipment Machinery replacement

    E xtern al/inter nal standar ds Fer tiliser /che mical application plans

    Maintenance plans

    Labour budget (peak loads)

    Operational planning: Determining activities in the comingcropping cycle, i.e. within the coming season

    Tactical production plan Required/optional operations

    Internal/external standards Operations urgency

    Maintenance plan for land, buildings and

    equipment

    Operations specifications

    Scheduling: Work scheduling setting up formulations ofjobs. Planning the implementation of work in the

    short-term.

    Required operations Work plan for planned operations indicating:

    Urgency of operations Starting time

    Soil and crop status Duration

    Weather forecast Work-sets requiredWorkability criteria

    Availability of labour and equipment

    Operations specifications

    Task formulation: Handling tasks concerning inspection offormulated tasks

    Equipment breakdowns Deviation from plans/schedules

    Unavailable material

    Change in soil, crop or weather conditions

    Priority changes

    Execution: Controlling tasks, and work-setsperformancetask control and operation control

    Work time elements (effective time, ancillary time,

    preparation time, disturbance time, etc.) on

    work-sets

    Realised work time

    Operations specifications

    Realised capacity

    Set point values for implement

    Evaluation: Comparing planned and actual executed tasks Realised work time Deviations from planned tasksRealised capacity

    Realised yield

    Documentation information

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    48 C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455

    include farm managers, machine controllers, external services, etc.A close coupling of the actors with the decision processes exists

    as the actors are the executers of these processes in terms of

    deciding which actions to take in relation to the execution of

    activities defined as operations (goal-specific work as required by

    the relevant production system) and tasks (the physical imple-

    mentation of the operation in terns of resources). The decision

    processes are influenced by a number of factors including strate-

    gies (e.g. the farmers preferences for a specific production form),

    triggers (e.g. weather conditions determining the planning and

    initiation of field operations), and timing (e.g. the degree of time-

    critical decision-making, where the operational decision-making

    is more time-critical than strategic decision-making). The infor-

    mation used in the decision process is the required information

    for making a rational decision, whereas the information produced

    by the decision process comprises the planning, guidance and

    control information used for actual implementing the specific deci-

    sion.

    The consecutive decision processes were organised into a dia-

    gram with a sequential timespan so that the decision processtogether with data transfer with different actors form an informa-tion flow through the different decision levels; strategic, tactical,operational, execution and evaluation. The farm specific data arestored in a database from which the data are available to a spe-cific decision process whenever needed. It is to be noticed that the

    timespan will vary according to the decision level as, for example,

    a decision process is faster in execution than in strategic planning.

    The outcome of this modelling is a devised information flow dia-

    gram (IFD). The aim of this user-centric IFD is to introduce the

    actors and their roles as needed in farmers decision-making asso-

    ciated the core tasks. As a result, it was easy to involve the farmers

    in developing and testing the model. Farmers were able to judge

    whether thedifferent details of theinformationflow in thediagram

    are correct and the proposed system usable for them.

    In this study, the information model was developed further

    from that reported in earlier studies. Here, six field operations

    were analyzed and modelled as IFD: tillage, seeding, fertilising,

    spraying, irrigation and harvesting. These are the main field oper-

    ations in crop production and have been as the focal point in the

    development of the FMIS in the FutureFarm project (Chatzinikos

    et al., 2009). By decomposing the activities inherent in the six field

    operations, the information, processes and actors involved in the

    decision-making were recorded. The earlier modelling work was

    evaluated, supplemented and expanded to cover the core task of

    European farm work by FutureFarmproject researchers. Whilst the

    main focus in previous work was in information management of

    mobile work units, the main focus here was on farm planning and

    real-time assistance. Thus, the automated compliance to standards

    and checking of plans was added as a technological advance in the

    modelling. The information models produced were cross-validatedwith the information modelling produced by Fountas et al. (2006)

    with its independent data set.

    Fig. 4. Legend describing used symbols and identified actors in information flow modelling.

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    C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455 49

    4. Results

    Fromthe six fieldoperations analyzedin the FutureFarmproject,

    the information model for the fertilisation case is presented in this

    paper. Table 1 sets the framework for the different decision lev-

    els together with the main parts of the information flows required

    by the decision process or produced by the decision process. By

    specifying in detail the information provided and the information

    required for the information handling processes, the design and

    functionalities of the individual information system elements can

    be derived. This has involved explicitly specifying tacit knowledge

    of the farmer as way to extend the FMIS design into automated

    decision-making.

    Thepresentation of theresults include a genericschematic illus-

    trates the symbols and the terms used in the information models.

    Next, the information models for the five levels of decisions are

    presented, that is strategic, tactical, operational, execution and

    evaluation.

    Fig. 4 shows the scope of the information modelling for the fer-

    tiliser case in termsof identifiedactors tobe included in thesystem.

    These actors include external entities outside the farm, the farmer

    as theprime decision maker andthe mobileunitentitiesinvolvedin

    actual carrying outof the planned tasks, such as the task controller,

    implement electronic control unit (ECU) and user interfaces likethe Virtual Terminal (VT) on the tractor. These mobile unit enti-

    ties, which are grouped using the dashed line, can be from one to

    many as during a field operation more than one fertilizer could be

    utilized. Also, the actor identification is applicable to both manned

    and unmanned mobile unit configurations.

    Specifically, external entities include the market receiving the

    produce from the farm production system, the advisory system

    providing advise to the farmer upon requests, the government

    system setting the rules and provisions for the farm production,

    the weather service providing weather information either gener-

    ally published or dedicated weather information upon request, the

    agricultural service companies like a machine contractor providing

    the service of executing specific work tasks, and the technology

    providers like agricultural machine dealers. As compared to the

    external entities, the internal entities include the farmer as the

    prime executor of decisions, the farm database as the container

    of farm relevant information, and the mobile unit entities compris-

    ing individual elements of the work machines on the farm. These

    latter elements involve information and communication measures

    as well as principal traction units like the tractor. Following the

    ISOBUS concept, the virtual terminal function as an interface to

    the ISOBUS compatible implements while the task controller is

    the prime communication device between the mobile unit and the

    management system. As the data acquisition part, the internal sen-

    sors provide information for the control of the planned task while

    the external sensors provide information about the field, environ-

    mental indicators, etc.As part of the strategic decision level, Fig. 5 focuses on the long-

    term potential production dimensions (vision) of the farm and

    involves a static description or analysis of the whole farm plan-

    Fig. 5. First part of strategic planning focusing on the farm development. The information transfer arrows to and from decision process are in a sequence.

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    50 C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455

    Fig. 6. Strategic planning focusing on the choice of technology according to the relevant standards and management practices.

    ning integrating the specifics of fertilising. External provisions like

    environmental requirements and standards for the application of

    fertiliser will influence the crop rotation scheme, the necessary

    technical capabilities of the equipmentfor fertiliserapplication,etc.

    Next, the fertilising strategy in terms of selected fertiliser types,

    strategies for application, etc. is determined based on an overall

    evaluation of the external requirements, the prices of production

    factors and sales products (Fig. 6). The selection of fertiliser equip-

    ment and the machinery size or capacity planning concerns both

    a qualitative and a quantitative selection of machinery items as

    related to the demand. The optimisation can be done by deter-

    mining (1) demands put up by the operation to be performed, (2)

    availability of equipmenton the market, (3) possibleworking meth-ods, (4) dimensions and capacity, (5) costs, and (6) use of own

    machinery or contractors. Many types of models supporting this

    optimisation have been launched, from simple deterministic mod-

    els (see for instance Hunt, 1983) to more complex simulation and

    linear programming models (e.g. Sgaard and Srensen, 2004). The

    models involve the interaction between the labour and machin-

    ery system and the biological and meteorological system involving

    crops, soil, weather conditions, etc. The optimisation is done

    while considering constraints like available labour and machinery,

    timeliness functions and workability. The strategical planning of

    machinery needs is strongly interconnected with the operational

    planning.If this connection is nottakeninto consideration, a strate-

    gically chosen plan could turn out to be non-executable, because it

    would produce a non-workable schedule.

    The determination of the necessary planning information in the

    subsequent planning levels is considered an integral part of the

    strategic selection of the fertilising technology. This involves deter-

    mining the scope of the information and the adherent information

    technology measures to be available as part of the tactical and

    operational planning of the fertiliser application.

    The tactical planning as depicted in Fig. 7 for the fertilising case

    concerns the determination of the quantity and timing of the oper-

    ational activity in the medium planning range.The tactical planning

    involves an all-year setting up of thefertiliser plans andoperational

    plans for the input of labour and machinery. Normative models for

    the labour and machinery input given a specific crop plan and a

    specific machinery inventory have been developed (e.g. Srensenand Nielsen, 2005; Achten, 1997). The maindecision involve select-

    ing the fertilising features of the application equipment in terms

    updated information from the technology provider, new adjust-

    ment features, etc. as well as acquiring planning information about

    available fertiliser types, recommendations on fertiliser use in the

    light of prevailing weather conditions, available external services

    which will be requested for service, etc.

    The input of labour and machinery will be constrained within

    the development of crop and weather, and consequently, peak

    load periods will be unavoidable (Nielsen and Srensen, 1994). To

    reduce the organisational impact of these peak load periods, crops

    requiring different periods for treatment have to be selected. How-

    ever, one thing, which reduces the impact of peak load periods

    significantly, is that the labour force in agriculture is rather flex-

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    C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455 51

    Fig. 7. Tactical planning focusing on in-season fertilising features and information acquisition for the fertilisation planning according to the strategy.

    ible when it comes to complying with the extra workload in these

    periods.

    The operational planning outlined in Fig.8 for thefertilisingcase

    concerns determining when a work operation will have to be exe-

    cuted in order to obtain a maximised work quality and maximum

    labour and machinery input effectiveness. Concerning the specific

    task of timing work operations, detailed job scheduling comes into

    play. In an agricultural context, scheduling is defined as determin-ing thetime, when various operations areto be performed. Availabilityof time, labour and machinery supply, job priorities and crop require-ments are some important factors (ASAE, 1974). Work schedulingis the formulation of jobs based on required operations. Jobs can

    be scheduled when soil, crop and weather conditions are withincertain limits. Planned jobs form the basis for task formulation (or

    implementation). Task formulation involves the actual specifica-

    tions of work-sets performing the tasks.

    The main decisions involve selecting the final data acquisition

    services that is required. That together with a subsequent direct

    inspection of the field conditions will determine the actual layout

    of the execution plan containing fertilising schedules, application

    rates, etc.

    The execution of the planned job in the operational planning

    phase focus on final scheduling, task control and documentation

    of realised work (Fig. 9). Task control concerns the work effi-

    ciency of work-sets (measured by time elements and compared

    with standard data). Operation control concerns the transforma-

    tion of operation specifications into set points for various parts

    of the equipment being used. Device control involves comparing

    machine operation (e.g. work quality) with planned specifica-

    tions.

    The main decision process in this phase involve the inspec-

    tion and controlling by the farm manager of the fertilising task

    by receiving information about the on-going task execution and

    take corrective actions if needed. Also, directly on the executing

    machine, a more or less automateddecision process is running tak-

    ing process information and converting it into actionable data for

    on-line correctivemeasures. The workperformance is recorded and

    the documentation data is stored to the farm database.

    The final step in planning and control cycle for the fertilis-

    ing operation involves the evaluation of the executed operation(Fig. 10). The documented field data need processing and aggre-

    gation in order to be useful in the evaluation. The key point is a

    comparison between the planned operation and the actual exe-

    cuted operation. The result of this comparison will be integrated

    in the subsequent planning cycle and will enable the manager to

    adapt to theactual or unexpected conditions on the farm. The feed-

    back increases the farmers situation awareness and readiness to

    act in unexpected situations. The farmer gains new knowledge and

    skills which he/she can utilise to improve the performance in the

    subsequent planning cycle.

    This phase involve 4 main decision processes: (a) data process-

    ing for documentation, (b) compliance with standards check, (c)

    summarising fertiliser performance, and (d) comparison with tar-

    get. External requirements for documentation as well as internal

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    C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455 53

    Fig. 9. Execution focusing on final scheduling, task control and documentation of realised work.

    are presented in order to discuss this connection. As a first exam-

    ple, the problem of machinery selection involved in the strategic

    planning level is considered. The intended optimisation tool is

    supporting the planning process choosing fertilising technology

    information and machinery and returning the output selected

    fertilizing technology (Fig. 6). A non-linear programming model

    like the one developed by Sgaard and Srensen (2004) may be

    invoked and comprise the capacity of the machine/s and the num-

    ber of the tractors and their power as decision variables. The

    input factors included field area, the fixed annual cost, operat-

    ing speed, working rate, repair and maintenance cost, and labour

    cost, the fuels costs, and expected crop price, and the timeliness

    cost.The second example regards the operational planning level

    (Fig. 8). Bochtis et al. (2009) presented a mission planer for an

    autonomous tractor covering also operations with capacity con-

    straints such as fertilising. The software could support the process

    formulating execution plan in the operational planning level pro-

    viding as output the tailored fertilising plans. The specific output

    is provided in an XML (extendible markup language) file deter-

    mining several actions related to the execution level including the

    sequence of points the tractor has to follow, the type of motion

    between successive points (e.g., straight motion or manoeuvring),

    the type of predefined turning routine used in manoeuvring, and

    the actions that should be taken once the tractor reaches the

    desired point (e.g., turning on or turning off the power take-off).

    The input for the mission planning optimisation problem involve

    the field geometry,facilityunit location,field tracks, etc. This infor-

    mation has been provided by the field inspection service by the

    actor external service, i.e. a GIS: geographic information system-

    database, or in the case that such a base does not exists, by the

    actor decision maker as a result of the process field inspection,

    i.e. recording the field boundary using an on-board GPS positioning

    receiver. The information machinery information provides the

    machinery related input, i.e. the minimum turning radius, oper-

    ating width, recommended operating speed, and tank capacity.

    In the same way, the process of the generation of the updated

    information in real-time systems refers to the execution level

    (Fig. 9), where this information provided by actors included in

    the machinery units (e.g., internal sensors, implement ECU, andexternal sensors). Optimisation algorithms that use information

    generated at this level are involved in cases such as the real-time

    planning of a fertilising unit in a sensor-based variable rate pre-

    cision spraying with some a priory information, i.e. by a satelliteimage (vehicle routing problem with stochastic demands) (Bochtis

    and Srensen, 2009), and the real-time planning for a refilling unit

    in the absence ofany a priory information (dynamic vehicle routingproblem with time windows) (Bochtis and Srensen, 2010).

    The described information models specify the key activities for

    the targeted agricultural operations and capture the management

    cycle of the farm (planning, implementation and evaluation). The

    design structure facilitates the building of a dedicated informa-

    tion management system as well as provides the foundation for

    developing targeted decision support systems. Other important

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    54 C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455

    Fig. 10. Evaluation part where documented raw execution data is processed further and aggregated for the comparative analyses.

    enhancement includes recording and storing of implement sta-

    tus/work documentation into farm database, increased usage of

    numerical/formative data, the Farm database has a central role in

    both human and machine decision-making, active use of external

    services increases, increased use of automation, and smart assist-

    ingsystem features to support work arecommon,used information

    management technology shifts towards knowledge management

    technology.

    6. Conclusions

    A user-centric approach to model the information flows for tar-geted field operations has been presented. The information models

    were centred aroundthe farmeras theprincipaldecisionmaker and

    involved external entities as well as mobileunit entities as themain

    information producers. By specifying in detail, the information pro-

    vided and the information required for the information handling

    processes,the design and functionalities of the individual informa-

    tion system elements can be derived. This has involved explicitly

    specifying tacit knowledge of the farmer as a way to extend the

    FMIS design into automated decision-making. The (IFDs) describe

    the systeminterface features of such a FMIS which gives support to

    farmers core task. In this study,a detailed approach to information

    modelling that will enable the generation of a Farm Management

    Information System in crop production, which is the main focus of

    the FutureFarm project, has been introduced.

    The user-centric information flow models propose the imple-

    mentation of effective managerial functions to the FMIS, but at the

    sametime, they expectthe farmers tobe ready to adopt new work-

    ing habits and perhaps also undergo further training. According to

    the modelling,farmerscan utilise differentservices moreefficiently

    and they are able to outsource some of the tasks they had previ-

    ously performed themselves. Also, farmers would be able to gain

    increased insight into their production processes and would able

    to evaluate the performance of the chosen technology. This would

    lead to better process control as well as an improved capability of

    documentingthe quality of farming e.g. traceability,to markets and

    administration.Finally, the proposed system would allow the farmers to access

    and utilise better scientific research and technological develop-

    ments by providing real process data and the ability to update the

    systems according to the latest knowledge.

    The enhancements from this approach would enable record-

    ing and storing of implement status or work documentation

    into farm database. This would also mean increased usage of

    numerical or formative data. Farm database would have a cen-

    tral role in both human and machine decision-making. Active

    use of external services as well as use of automation and smart

    assisting system features to support work would increase. This

    would be especially important in the future when information

    management technology shifts towards knowledge management

    technology.

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    C.G. Sorensen et al. / Computers and Electronics in Agriculture 73 (2010) 4455 55

    Acknowledgements

    This project was part of the collaborative research project

    FutureFarm. The research leading to these results has received

    funding from the European Communitys Seventh Framework Pro-

    gramme (FP7/2007-2013) under grant agreement no. 212117.

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