࡞ͷੜҭʹΑΔӄྖҬͷมԽΛߟྀͨ͠
ιʔϥʔύωϧηϯαϊʔυͷҠಈεέδϡʔϦϯά๏
ߐ౻ େ
1,a)উؒ ྄
2,b)ۄҪ
1,c)҆ຊ ܚҰ
1,d) ֓ཁɿۙɼଠཅޫͳͲͷڥΤωϧΪʔ͔ΒిྗΛ֫ಘ͢ΔΤφδʔϋʔϕεςΟϯάΛར༻ͨ͠ ແઢηϯαωοτϫʔΫ(WSN)͕͞Ε͍ͯΔɽΤφδʔϋʔϕεςΟϯάʹΑΔిྗڙڅΛར༻͢ Δ͜ͱʹΑͬͯɼωοτϫʔΫण໋ͷӬٱԽɼωοτϫʔΫҡ࣋ͷͨΊͷίετͷݮ͕ظ͞ΕΔɽ ͔͠͠ɼଠཅޫΛ༻͍ͨΤφδʔϋʔϕεςΟϯάরྔʹΑͬͯൃిྔ͕มԽ͠ɼಛʹӄͷྖҬͰ রྔ͕গͳ͘ɼेͳൃిྔ͕ظͰ͖ͳ͍ɽطଘݚڀͰɼఱؾʹΑΔরྔͷมԽΛߟྀͯ͠ωο τϫʔΫण໋ΛԆ͢Δख๏͕ఏҊ͞Ε͍ͯΔɽ͔͠͠ɼۀ༻Ͱ༻͞ΕΔWSNͰӄͷྖҬ͕ ࡞ͷੜҭঢ়گقઅ͝ͱͷଠཅߴʹΑͬͯมԽ͍ͯ͘͠ɽͦͷͨΊɼൃిྔ͕ෆेͳϊʔυ͕ൃ ੜ͠ɼͦΕΒͷిྗ͕ૣٸʹރׇ͢Δ͜ͱͰωοτϫʔΫશମΛظؒҡ࣋Ͱ͖ͳ͘ͳΔͱ͍͏͕͋ Δɽ·ͨɼۀ༻ͳͲͰఆظతʹԹ࣪ͷใΛऩू͢ΔͨΊʹηϯαϊʔυͰରྖҬΛৗʹ ඃ෴͢Δ͜ͱ͕ٻΊΒΕΔɽͦ͜ͰຊݚڀͰɼରྖҬΛશඃ෴ͭͭ͠ɼҐஔͱ࣌ʹԠͨ͡ൃిྔΛ ༧ଌ͢Δ͜ͱʹΑͬͯɼిྔͷগͳ͍ϊʔυͷൃిྔ͕େ͖͘ͳΔΑ͏ʹ֤ϊʔυΛμΠφϛοΫʹ Ҡಈͤ͞Δख๏ΛఏҊ͢ΔɽιʔϥʔύωϧΛ༻͍ͨॆిػߏ͓ΑͼҠಈػߏΛඋͨ͠ηϯαϊʔυΛ ࡞͠ɼωοτϫʔΫण໋ͷԆ߹͍ʹ͍ͭͯɼҠಈػߏΛ࣋ͨͳ͍ϊʔυͱͷൺֱʹΑΔධՁΛߦ͏ɽMovement Scheduling Method of Sensor Nodes with Solar Panel
Considering Shadowy Area Change by Crop Growth
Eto, Masaru
1,a)Katsuma, Ryo
2,b)Tamai, Morihiko
1,c)Yasumoto, Keiichi
1,d)Abstract: In recent years, wireless sensor networks (WSNs) using energy harvesting have been attracting
increasing attention. Power supply by energy harvesting is expected to increase lifetime of WSNs and to reduce the cost of network maintenance. However, electric power generation by energy harvesting using solar power is not always enough because it depends on intensity of solar radiation. In particular, intensity of solar radiation of shadowy area is low. Then, some methods to extend lifetime of WSNs are proposed that consider changing of intensity of solar radiation depending on weather. However, shadowy area changes by crop growth and solar altitude in agricultural site. Therefore, electric power generation of some nodes may become insufficient and cause a problem in maintenance of WSNs. Also, it is required that sensor nodes cover the field any time to periodically collect environmental information. In this paper, we propose a movement scheduling method that increases electric power generation of nodes with low battery by predicting amount of electric power generation based on position of node, time and date. We assemble a sensor node with charger using solar panel and moving apparatus and evaluate lifetime of WSNs by comparing our method with a method without moving apparatus of sensor node.
1 ಸྑઌՊֶٕज़େֶӃେֶ
Nara Institute of Science and Technology 2 େࡕཱେֶ
Osaka Prefecture University a) [email protected] b) [email protected] c) [email protected]
1.
͡Ίʹ
ۙɼଟͷηϯαϊʔυʹΑͬͯߏங͞ΕΔແઢηϯ αωοτϫʔΫ(ҎԼɼWSN)͕͞Ε͍ͯΔɽWSN d) [email protected]ʹఆظతʹڥใΛऩू͢ΔσʔλऩूܕWSN͕͋ ΔɽσʔλऩूܕWSNͰɼ֤ηϯαϊʔυ͕Ұఆ࣌ؒ ͝ͱʹڥใΛηϯγϯά͠ɼηϯγϯάσʔλΛແઢ Ϛϧνϗοϓ௨৴ʹΑͬͯجہʹૹ৴͢Δɽσʔλऩू ܕWSNͷྫͱͯ͠ۀ༻ʹ͓͍ͯɼԹ࣪ͳͲͷ ڥใΛऩू͢ΔΞϓϦέʔγϣϯ͕͋Δ[1], [2]ɽۀ ༻ͷڥใΛऔಘ͢Δ͜ͱʹΑͬͯɼͦͷ࡞͕ੜҭ ͍͢͠ڥͳͷ͔Ӹප͕ൃੜ͍͢͠ڥͳͷ͔Λ Δ͜ͱ͕Ͱ͖Δɽ͜ͷΑ͏ͳΞϓϦέʔγϣϯͰɼηϯ γϯάରͱ͢ΔྖҬશମΛৗʹඃ෴͢Δ͜ͱͱɼඞཁͳ ظؒҎ্ωοτϫʔΫ͕ಈ࡞͢Δ͜ͱ͕ٻΊΒΕΔɽωο τϫʔΫण໋ԆͷͨΊͷٕज़ͱͯ͠ɼΤφδʔϋʔϕε ςΟϯά[3]͕͞Ε͍ͯΔɽΤφδʔϋʔϕεςΟϯ άͱɼଠཅޫͳͲͷڥΤωϧΪʔ͔ΒిྗڙڅΛ ߦ͏ٕज़Ͱ͋ΔɽιʔϥʔύωϧԹࠩʹΑΔൃిૉࢠ ͳͲΛར༻͢Δ͜ͱʹΑͬͯɼηϯαϊʔυʹిྗΛڙڅ ͢Δ͜ͱ͕Ͱ͖ΔɽͦͷͨΊɼैདྷͷηϯαϊʔυόο ςϦ͕ރׇ͢Δͱͦͷϊʔυར༻Ͱ͖ͳ͘ͳ͍͕ͬͯͨɼ ڥΤωϧΪʔ͔ΒిྗͷڙڅΛ͢Δ͜ͱʹΑͬͯόος ϦΛճ෮ͤ͞Δ͜ͱ͕Ͱ͖ɼωοτϫʔΫͷण໋Ԇ͠ ͘ӬٱԽ͕ظ͞ΕΔɽ͔͠͠ͳ͕ΒɼΤφδʔϋʔ ϕεςΟϯάʹΑΔిྗͷڙڅɼڥʹґଘ͢ΔͨΊൃ ిྔ͕ෆ҆ఆͰ͋Δͱ͍͏͕͋Δɽྫ͑ɼଠཅޫ Λར༻ͨ͠ൃిͰɼࣹྔʹΑͬͯιʔϥʔύωϧͷൃ ిྔ͕มԽ͢Δɽ·ͨɼࣹྔఱީɼقઅʹΑΔଠཅͷ يಓোʹΑΔӄͷӨڹΛड͚ΔͨΊɼҐஔ࣌ ʹΑͬͯมԽ͢Δɽ ͦ͜ͰɼఱީଠཅͷيಓΛߟྀͨ͠WSNͷݚڀ͕ߦ ΘΕ͍ͯΔɽจݙ[4]Ͱɼ࣌ؒͰมԽ͢ΔଠཅͷϓϩϑΝ ΠϧʹΑͬͯɼηϯαϊʔυͷηϯγϯάൣғΛ੍ޚ͠ɼ ࠷খͷϊʔυͰରྖҬΛඃ෴͢Δख๏ΛఏҊ͍ͯ͠ Δɽ·ͨɼจݙ[5]ͰɼఱީͷมԽΛߟྀͨ͠ൃిྔͷ ༧ଌΛߦ͍ɼόοςϦʹ༨༟͕͋Δϊʔυʹσʔλͷதܧ Λͤ͞Δ͜ͱͰωοτϫʔΫͷण໋ΛԆ͢Δख๏ΛఏҊ ͍ͯ͠Δɽ͔͠͠ɼ͜ΕΒͷݚڀͰɼӄʹΑΔൃిྔ ͷมԽΛߟྀ͍ͯ͠ͳ͍ɽӄͷྖҬɼͷྖҬʹൺ ͯൃిྔ͕গͳ͘ɼηϯαϊʔυͷόοςϦ͕ރׇͯ͠ ͠·͏Մೳੑ͕ߴ͍ɽ ͦ͜ͰຊݚڀͰɼରྖҬΛશඃ෴ͭͭ͠ɼҐஔͱ ࣌ʹԠͨ͡ൃిྔΛ༧ଌ͢Δ͜ͱʹΑͬͯɼిྔͷগ ͳ͍ϊʔυͷൃిྔ͕େ͖͘ͳΔΑ͏ʹ֤ϊʔυΛμΠφ ϛοΫʹҠಈͤ͞Δख๏ΛఏҊ͢Δɽ ຊݚڀͰɼۀ༻ʹ͓͍ͯఆظతʹڥใΛऔಘ ͢ΔWSNΛఆ͢Δɽۀ༻Ͱɼ࡞ʹΑΔӄͷ ྖҬ͕ൃੜ͠ɼ࡞͕ੜҭ͢Δ͜ͱʹΑͬͯӄͷྖҬ͕ มԽ͍ͯͨ͘͠ΊɼҐஔ࣌ʹΑࣹͬͯྔ͕มԽ͢Δɽ ηϯαϊʔυιʔϥʔύωϧΛར༻ͨ͠ॆిɼηϯγϯ άɼσʔλͷૹड৴͓ΑͼҠಈΛߦ͏͜ͱ͕Ͱ͖ΔͱԾఆ ͢Δɽ ఏҊख๏Ͱɼ֤ηϯαϊʔυ͕ݱࡏͷҐஔͱ͔࣌Β ࣗͷൃిྔΛ༧ଌ͢Δɽ༧ଌͨ͠ൃిྔΛۙྡͷϊʔυ ͱൺֱ͠ɼҠಈʹΑΔফඅిྗͱҠಈޙͷൃిྔΛߟྀ͠ ͯɼηϯαϊʔυͷిྔ͕࠷େʹͳΔΑ͏ʹϊʔυΛ Ҡಈͤ͞Δɽ ҎԼɼ2ষͰɼઃఆʹ͍ͭͯड़Δɽ3ষͰɼఏ Ҋख๏ʹ͍ͭͯड़Δɽ4ষͰɼηϯαϊʔυͷ࣮ํ ๏ʹ͍ͭͯड़Δɽ5ষͰɼωοτϫʔΫͷण໋ʹ͍ͭ ͯҠಈػߏΛ࣋ͨͳ͍ϊʔυͱͷൺֱʹΑΔධՁํ๏Λݕ ౼͢Δɽ6ষͰɼ·ͱΊΛड़Δɽ
2.
ઃఆ
ຊষͰɼຊߘͰऔΓѻ͏WSNͷϞσϧ͓ΑͼͦͷԾ ఆΛࣔ͢ɽ 2.1 WSNϞσϧ ຊݚڀͰɼۀ༻ʹ͓͍ͯԹ࣪ͳͲͷڥ ใΛऩू͢ΔΞϓϦέʔγϣϯΛఆ͢Δɽͦ͜Ͱɼଟ ͷηϯαϊʔυ͕ରྖҬʹஔ͞Εɼఆظతʹڥใ Ληϯγϯά͠ɼϚϧνϗοϓ௨৴ͰجہʹσʔλΛ ૹ৴͢ΔσʔλऩूܕWSNΛରͱ͢Δɽଟͷηϯα ϊʔυ͕ηϯγϯά͓ΑͼσʔλऩूΛߦ͏ͨΊͷωοτ ϫʔΫΛߏங͢Δɽ·ͨɼରྖҬͷʹجہΛઃஔ͠ɼ جہόοςϦΕΛى͜͞ͳ͍ͷͱ͢Δɽ ιʔϥʔύωϧΛ༻͍ͨΤφδʔϋʔϕεςΟϯάͰ ɼൃిྔࣹྔʹΑͬͯมԽ͢Δɽ·ͨɼࣹྔ ӄͷྖҬͱఱީʹΑͬͯมԽ͢Δɽۀ༻Ͱɼӄͷ ྖҬଠཅͷҐஔͱ࡞ͷੜҭঢ়گʹΑܾͬͯఆ͞ΕΔɽ ࡞ԁਲ਼ঢ়ʹ͢Δͱ͠ɼࣜ(1)ͷϩδ εςΟοΫۂઢ[6]ʹै͏ͷͱ͢Δɽ Nt= K 1 + ( K Nt−1− 1)e−n (1) ͜͜ͰɼNt࣌ࠁtʹ͓͚Δ࡞ͷߴ͞[m]ɼK࡞ ͷߴ͞ͷ্ݶ[m]ɼnͰ͋Δɽ ·ͨɼ࣌ࠁʹΑΓଠཅͷҐஔ͕มԽ͠ɼ·ͨɼقઅʹΑ Γଠཅͷيಓ͕มԽ͢Δɽ͞ΒʹɼࣹྔఱީʹΑͬͯ มԽ͠ɼఱࣹ࣌ྔ͕େ͖͘ɼಶఱࣹ࣌ྔ͕খ ͍͞ɽͦ͜ͰɼࣹྔϞσϧͱͯ͠ɼ࣌ࠁtʹ͓͚Δఱ ࣌ͷͷྖҬͷࣹྔΛcsunny(t)ɼఱ࣌ͷӄͷྖ ҬͷࣹྔΛcshadowy(t)ɼಶఱ࣌ͷࣹྔΛccloudy(t)ͱ ͢Δɽ ηϯαϊʔυιʔϥʔύωϧͱೋ࣍ిΛඋ͓͑ͯΓɼ ଠཅޫʹΑΔൃిͰೋ࣍ిʹॆి͢Δ͜ͱ͕Ͱ͖Δɽ· ͨɼηϯαϊʔυԹ࣪ͳͲͷڥใͷηϯγϯ άɼσʔλͷૹड৴͓ΑͼҠಈΛߦ͏͜ͱ͕Ͱ͖Δɽۀ ༻ʹ͓͍ͯηϯαϊʔυɼ࡞͕২͑ΒΕ͍ͯΔՕॴ*1ͷՕॴҠಈ͢Δ͜ͱ͕Ͱ͖ͳ͍ɽͦͷͨΊɼηϯ αϊʔυରྖҬͷܾΊΒΕͨྖҬͷΈͰ͔͠ҠಈͰ ͖ͳ͍ɽ 2.2 ిྗϞσϧ ηϯαϊʔυೋ࣍ిΛ࣋ͪɼιʔϥʔύωϧʹΑΔ ॆి͕Ͱ͖Δɽࣹྔc[M J/m2]ͷͱ͖ͷɼιʔϥʔύω ϧʹΑΔൃిిྗCharge(c)Լࣜ(2)ʹै͏ͷͱ͢Δɽ Charge(c) = c× Egen (2) ͜ ͜ Ͱ ɼEgen ι ʔ ϥ ʔ ύ ω ϧ ʹ Α Δ ୯ Ґ ࣹ ྔ [M J/m2]ͨΓͷൃిྔͰ͋Δɽ ·ͨɼηϯαϊʔυσʔλͷૹड৴ɼηϯγϯά͓Α ͼҠಈ࣌ʹిྗΛফඅ͢Δɽ x[bit] ͷ σ ʔ λ Λ d[m] ૹ ৴ ͢ Δ ͨ Ί ͷ ి ྗ ྔ T rans(x, d)ɼ͓ Α ͼ ɼx[bit]Λ ड ৴ ͢ Δ ͨ Ί ͷ ి ྗ ྔ Recep(x)Լࣜ(3)ɼ(4)ʹै͏ͷͱ͢Δ[7]ɽ
T rans(x, d) = Eelec× x + εamp× x × d2[J ] (3)
Recep(x) = Eelec× x[J] (4)
͜͜ͰɼEelecϋʔυΣΞͷফඅిྗɼεamp ৴߸૿෯ثͷফඅిྗͰ͋Δɽ
ηϯγϯάʹΑͬͯD[bit]ͷσʔλΛऔಘ͢ΔͨΊͷి
ྗྔSens()Լࣜ(5)ʹै͏ͷͱ͢Δɽ
Sens() = Eelec× D + Esens (5)
͜͜ͰɼEsensηϯγϯάͷͨΊͷిྗফඅͰ ͋Δɽ ηϯαϊʔυ͕d[m]Ҡಈ͢ΔͨΊͷిྗྔM ove(d) Լࣜ(6)ʹै͏ͷͱ͢Δ[8]ɽ M ove(d) = d× Emove (6) ͜͜ͰɼEmove1[m]Ҡಈ͢ΔͨΊʹফඅ͢Δిྗྔ Ͱ͋Δɽ 2.3 ͷఆࣜԽ ຊͷೖྗͱͯ͠ɼରྖҬF ieldɼϊʔυsͷҐஔ s.posɼϊʔυsͷηϯγϯάܘs.rɼϊʔυsͷిྔ
s.energyɼఆKɼnɼcsunny(t)ɼcshadowy(t)ɼccloudy(t)ɼ
EgenɼEelecɼεampɼEsensɼEmoveɼηϯγϯάִؒIɼη
ϯγϯάͰऔಘ͢ΔσʔλαΠζDΛ༩͑Δɽग़ྗɼ֤ ϊʔυͷҠಈεέδϡʔϧͰ͋Δɽ͜͜ͰɼϊʔυsͷҠ ಈεέδϡʔϧͱɼ֤࣌ࠁtʹ͓͚ΔsͷҐஔs.pos(t) ͷ͜ͱͰ͋Δɽ ϊʔυͷҠಈɼରྖҬͷશඃ෴͕อͨΕΔΑ͏ʹ͠ ͳ͚ΕͳΒͳ͍ɽରྖҬͷશඃ෴͕Ͱ͖ͳ͘ͳΔ࣌ࠁ *1 ࡞Λੜҭͤ͞ΔͨΊʹΛΓ্͛ͨՕॴ Λtlif eͱ͢Δͱɼ͜ͷ੍ҎԼͷࣜ(7)Ͱද͢͜ͱ͕Ͱ ͖Δɽ
∀t ∈ [tstart, tlif e),∀pos ∈ F ield, |Cover(pos, t)| ≥ 1(7) ͜͜ͰɼtstartWSNͷՔಇ։࢝࣌ࠁɼCover(pos, t)
࣌ࠁtʹ͓͍ͯҐஔposΛඃ෴͍ͯ͠Δηϯαϊʔυ
Λࣔ͠ɼࣜ(8)Ͱఆٛ͞ΕΔɽ
Cover(pos, t)
=|{s||s.pos(t) − pos| ≤ s.r ∧ s.energy(t) > 0}| (8)
·ͨɼηϯαϊʔυ͕ࣗͷηϯγϯάൣғΛඃ෴͢Δ ͨΊʹɼ֤࣌ࠁͰσʔλͷૹड৴ɼ͓Αͼɼηϯγϯά Λ͢ΔͨΊͷిྔ͕͍ͬͯΔඞཁ͕͋Δɽ͜ͷ੍ Λࣜ(9)Ͱࣔ͢ɽ
∀t ∈ [tstart, tlif e), s.energy(t)
−T rans(x, d) − Recep(y) − Sens() > 0 (9)
͜͜Ͱɼx͕ࣗૹ৴͢ΔηϯγϯάσʔλͷαΠζ [bit]ɼdૹ৴͢Δྡϊʔυͱͷڑ[m]ɼyଞͷϊʔ υ͔Βड৴͢ΔσʔλͷαΠζ[bit]Ͱ͋Δɽ ·ͨɼ֤࣌ࠁͰϊʔυ͕Ҡಈ͢Δ߹ɼҠಈ͢ΔͨΊͷ ిྗྔҎ্ͷిྔ͕͍ͬͯΔඞཁ͕͋Δɽ͜ͷ੍ Λࣜ(10)Ͱࣔ͢ɽ
∀t ∈ [tstart, tlif e), s.energy(t)− Move(l) > 0 (10)
͜͜Ͱɼlϊʔυ͕ҰʹҠಈ͢Δڑ[m]Ͱ͋Δɽ
ຊɼωοτϫʔΫण໋tlif eΛ࠷େԽͤ͞Δɼϊʔ υͷҠಈεέδϡʔϧΛܾఆ͢Δ͜ͱͰ͋Γɼతؔ Լࣜ(11)Ͱࣔ͞ΕΔɽ
maximize(tlif e) subject to (7), (9) and (10) (11)
3.
ൃిྔ༧ଌʹجͮ͘ηϯαϊʔυͷҠಈε
έδϡʔϦϯά๏
֤ηϯαϊʔυɼt࣌ؒޙͷιʔϥʔύωϧʹΑΔൃ ిྔͱσʔλૹड৴ηϯγϯάʹΑΔফඅిྗྔΛ༧ଌ ͠ɼిྔΛٻΊΔɽ༧ଌͨ͠ൃిྔɼফඅిྗྔɼి ྔΛۙྡϊʔυͱަ͠ɼҠಈͨ͠߹ͱҠಈ͠ͳ͔ͬ ͨ߹ͷt࣌ؒޙͷిྔΛൺֱ͠ɼηϯαϊʔυͷt ࣌ؒޙͷిྔͷ࠷খ͕࠷େʹͳΔΑ͏ʹҠಈ͢Δɽ 3.1 ରྖҬͷඃ෴ ରͱ͢ΔWSNͰɼରྖҬΛৗʹશඃ෴͠ͳ͚Ε ͳΒͳ͍ɽͦ͜Ͱɼਤ1ʹࣔ͢Α͏ʹɼηϯαϊʔυͷ ηϯγϯάܘs.rʹରͯ͠ɼରྖҬΛ1ล s.r√ 2 ͷਖ਼ํ ܗͷάϦουʹׂ͢Δɽ֤άϦουʹηϯαϊʔυ͕ 1ͭҎ্ଘࡏ͍ͯ͠ΕɼͦͷάϦουඃ෴͍ͯ͠Δͱ䝉䞁䝃 䝜䞊䝗 ਤ1 ରྖҬͷׂ ͢Δɽ·ͨɼͯ͢ͷάϦουʹηϯαϊʔυ͕1ͭҎ্ ଘࡏ͍ͯ͠ΕɼରྖҬΛશඃ෴͍ͯ͠Δ͜ͱʹͳΔɽ ηϯαϊʔυɼҠಈʹΑͬͯݱࡏͷάϦου͔Βग़ͯ ͠·͏߹ʹɼάϦουʹผͷηϯαϊʔυ͕ଘࡏ͢Δ ͔ɼଞͷάϦου͔Βηϯαϊʔυ͕Ҡಈͯ͘͠Δ͔ͱ͍ ͏ใΛۙྡϊʔυ͔Βऔಘ͢Δɽ͠ɼҠಈʹΑͬͯݱ ࡏͷάϦουʹηϯαϊʔυ͕1ͭଘࡏ͠ͳ͘ͳΔ߹ ʹҠಈ͠ͳ͍ɽͨͩ͠ɼ2ͭͷϊʔυؒͰҐஔΛަ͢ Δ߹ʹඃ෴ͷঢ়ଶมΘΒͳ͍ͨΊɼۙྡϊʔυͷঢ় گʹؔͳ͘ҠಈΛߦ͏ɽ 3.2 ൃిɾফඅిྗ༧ଌʹΑΔҠಈ ֤ηϯαϊʔυɼඇಉظʹൃిྔͱফඅిྗྔͷ༧ଌ Λߦ͍ɼҠಈͷஅΛߦ͏ɽ ·ͣɼηϯαϊʔυɼࣗͷҐஔใͱ͔࣌Β࣌ ࠁt0͔Βt࣌ؒޙ·Ͱͷൃిྔͷ༧ଌΛߦ͏ɽաڈͷ ࣹྔͷσʔλ[9]ͷ͏ͪɼఱ࣌ͷશఱࣹྔΛ࣌ࠁt1 ʹ͓͚Δͷࣹྔcsunny(t1)ɼఱ࣌ͷࢄཚࣹྔΛ ࣌ࠁt1ʹ͓͚Δӄͷࣹྔcshadowy(t1)ɼಶఱ࣌ͷશ ఱࣹྔΛ࣌ࠁt1ʹ͓͚Δࣹྔccloudy(t1)ͱ͢Δɽ͞ Βʹɼ࡞ͷͱଠཅͷيಓ͔Βɼ࣌ࠁt1ʹ͓͚Δࣗ ͷҐஔ͕͔ӄ͔Λ༧ଌ͠ɼఱ࣌ͷͳΒ asunny(t1) = 1ɼఱ࣌ͷӄͳΒashadowy(t1) = 1ɼಶ ఱ࣌ͳΒacloudy(t1) = 1ͱ͢ΔɽٻΊࣹͨྔͱιʔ ϥʔύωϧͷੑೳΛجʹɼࣜ(12)Λ༻͍ͯൃిిྗΛܭ ࢉ͢Δɽ Charge(c) = Egen× t0+t k=t0 (csunny(k)× asunny(k) + cshadowy(k)× ashadowy(k) + ccloudy(k)× acloudy(k)) (12) ࣍ʹɼ࣌ࠁt0͔Βt࣌ؒޙ·Ͱͷσʔλૹड৴ɼηϯγ ϯά͓Αͼػ࣌ؒʹΑΔফඅిྗྔͷ༧ଌΛߦ͏ɽ2.2 અͷిྗϞσϧΛ༻͍ͯɼηϯγϯάΛߦ͏ִؒͦΕ· Ͱʹૹड৴ͨ͠σʔλ͔ΒɼফඅిྗྔΛܭࢉ͢Δɽ ٻΊͨ༧ଌൃిྔͱ༧ଌফඅిྗྔ͔Βɼt࣌ؒޙͷ༧ ଌిྔΛܭࢉ͢Δɽۙྡϊʔυͷ༧ଌిྔΛऔಘ ͠ɼͦΕͧΕͷϊʔυͱҐஔΛަͨ͠߹ͷ༧ଌి 䝉䞁䝃 䝜䞊䝗㻭 㻮 㻯 ண Ⓨ㟁㔞 㟁ụṧ㔞 㻮 㻭 㻯 ਤ2 ൃిྔͱফඅిྗྔͷ༧ଌʹجͮ͘ϊʔυͷҐஔަͷྫ ද1 ϊʔυͷిྔɼ༧ଌൃిɾফඅిྗྔ ϊʔυA ϊʔυB ϊʔυC i.energy 30% 60% 40% Charge(c) 15% 30% 20% Consumption(t, t, i.pos) 10% 15% 10% ྔΛܭࢉ͢Δɽ͜ͷ࣌ɼ༧ଌফඅిྗྔʹҠಈ࣌ʹൃੜ͢ ΔফඅిྗΛ͢ɽҠಈͨ͠߹ͱҠಈ͠ͳ͔ͬͨ߹ ͰɼͦΕͧΕۙྡϊʔυͷதͰ࠷খͷ༧ଌిྔΛٻΊ ΔɽҠಈͨ͠߹ͷ࠷খ༧ଌిྔͷํ͕େ͖͍߹ʹ ɼϊʔυͷҠಈΛߦ͏ɽ ಈ ࡞ ྫ Λ ਤ 2 ʹ ࣔ ͢ ɽਤ 2ʹ ͓ ͚ Δ ֤ ϊ ʔ υ ͷ ి ྔ ɼ༧ ଌ ൃ ి ྔ ɼ༧ ଌ ফ අ ి ྗ ྔ Λ ද 1ʹ ࣔ ͢ ɽ
Consumption(t, t, i.pos)ϊʔυiͷҐஔi.posʹ͓͚
Δ࣌ࠁtͷt࣌ؒޙ·Ͱͷηϯγϯά͓Αͼσʔλૹड৴ Ͱͷ༧ଌফඅిྗྔͰ͋Δɽ·ͨɼ֤ϊʔυؒͰҐஔΛަ ͨ͠߹ʹҠಈͰফඅ͢ΔిྗΛ5%ͱ͢Δɽ͜͜Ͱɼ Ҡಈ͠ͳ͍߹ͷͦΕͧΕͷt࣌ؒޙͷిྔɼͦΕ ͧΕ35%ɼ75%ɼ50%ͱͳΔɽ·ͨɼϊʔυAͱB͕Ґஔ Λަͨ͠߹ͷt࣌ؒޙͷిྔɼͦΕͧΕ40%ɼ 60%ɼ50%ͱͳΔɽҠಈͨ͠߹ͷํ͕ɼిྔͷ࠷খ ͕େ͖͘ͳΔͨΊϊʔυAͱB͕ҐஔΛަ͢Δɽ
4.
ηϯαϊʔυͷ࣮ํ๏
ຊষͰɼηϯαϊʔυͷ࣮ํ๏ʹ͍ͭͯड़Δɽ ηϯαϊʔυɼηϯαػߏɼ௨৴ػߏɼॆిػߏɼҠ ಈػߏ͔ΒͳΔɽ ηϯαػߏɼԹηϯαͱ࣪ηϯαΛ࣋ͪɼԹͱ ࣪ͷηϯγϯάΛߦ͏ɽ ௨৴ػߏɼZigBeeʹΑΔແઢ௨৴Λߦ͏͜ͱ͕Ͱ͖ɼ ηϯγϯάσʔλͷجہͷૹ৴͓Αͼϊʔυใͷૹ ड৴Λߦ͏ɽ·ͨɼZigBeeͷϝογϡϧʔςΟϯάΛ༻͍ ͯɼωοτϫʔΫͷߏங͓ΑͼϧʔςΟϯάΛߦ͏ɽ ॆిػߏɼιʔϥʔύωϧʹΑΔൃిΛߦ͏͜ͱ͕Ͱ ͖Δɽ·ͨɼ࠷େిྗै(MPPT)ճ࿏ʹΑΓɼιʔ ϥʔύωϧ͔ΒͷిྗΛॆిʹඞཁͳిѹɾిྲྀʹίϯ όʔτ͢Δɽ Ҡಈػߏɼ4ྠʹର͠ࠨӈ2ͭͷDCϞʔλͰۦಈྠ Λಈ࡞ͤ͞ΔɽϞʔλυϥΠόʹΑΓɼલసɾٯసΛ੍ޚ͢Δ͜ͱͰલਐɾޙਐɾճసΛ͢Δ͜ͱ͕Ͱ͖Δɽ
5.
ධՁํ๏
ຊষͰɼࠓޙߦ͏༧ఆͰ͋ΔධՁͷ֓ཁʹ͍ͭͯड़ Δɽ ఏҊख๏ͷ༗ޮੑΛࣔͨ͢ΊʹςετϕουͰͷ࣮ݧͱ ܭࢉػγϛϡϨʔγϣϯʹΑΔධՁΛߦ͏ɽධՁɼର ྖҬʹηϯαϊʔυΛஔ͠ɼڥใΛҰఆ࣌ؒ͝ͱʹ ऩूͨ͠ͱ͖ͷωοτϫʔΫͷण໋͓Αͼɼిྔʹ ΑͬͯධՁΛߦ͏ɽωοτϫʔΫͷण໋ͱରྖҬ͕શ ඃ෴͞Ε͍ͯΔ࣌ؒͰ͋ΓɼWSN͕ߏங͞Ε͔ͯΒ1ͭ Ҏ্ͷάϦουͰϊʔυ͕ଘࡏ͠ͳ͍ঢ়گʹͳΔ·Ͱͷ࣌ ؒͰ͋Δɽ·ͨɼిྔωοτϫʔΫण໋͕ਚ͖ͨͱ ͖ͷిྔͷภΓΛධՁ͢Δɽ2ͭͷධՁ߲ʹ͍ͭͯɼ ҠಈػߏΛ࣋ͬͨηϯαϊʔυΛ༻͍ͨ߹ͱҠಈػߏΛ ࣋ͨͳ͍ηϯαϊʔυΛ༻͍ͨ߹ͱͰൺֱΛߦ͏ɽ 5.1 γϛϡϨʔγϣϯʹ͓͚ΔγφϦΦ γϛϡϨʔγϣϯͰɼରྖҬʹϥϯμϜʹϊʔυΛ ஔ͠ɼWSNΛߏங͢Δɽ͜ͷ࣌ɼҠಈػߏΛ࣋ͨͳ͍ ϊʔυͰશඃ෴Ͱ͖ΔΑ͏ʹ֤άϦουʹ1ͭҎ্ͷ ϊʔυஔ͢Δɽ֤ηϯαϊʔυఆظతʹڥใΛη ϯγϯά͠ɼηϯγϯάσʔλΛແઢϚϧνϗοϓʹΑͬ ͯجہʹૹ৴͢Δɽ6.
·ͱΊ
ຊߘͰɼΤφδʔϋʔϕεςΟϯάΛར༻ͨ͠WSN ʹ͓͍ͯɼରྖҬΛશඃ෴ͭͭ͠ɼҐஔͱ࣌ʹԠͨ͡ ൃిྔΛ༧ଌ͢Δ͜ͱʹΑͬͯɼిྔͷগͳ͍ϊʔυ ͷൃిྔ͕େ͖͘ͳΔΑ͏ʹ֤ϊʔυΛμΠφϛοΫʹҠ ಈͤ͞Δख๏ΛఏҊͨ͠ɽࠓޙɼηϯαϊʔυΛ࡞͠ɼ খنͳςετϕουʹΑΔධՁͱςετϕουͰಘΒΕ ͨσʔλΛجʹͨ͠େنͳγϛϡϨʔγϣϯʹΑΔධՁ Λߦ͏༧ఆͰ͋Δɽ ࢀߟจݙ[1] Langendoen, K., Baggio, A., Visser, O. “Murphy Loves Potatoes Experiences from a Pilot Sensor Network De-ployment in Precision Agriculture,” 14th Int’l.
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[2] Hwang, J., Shin, C., Yoe, H. “A Wireless Sensor Network-Based Ubiquitous Paprika Growth Manage-ment System,” Sensors 2010, 10, pp.11566–11589, 2010. [3] Chalasani, S., Conrad,J. “A survey of energy harvesting sources for embedded systems,” Proc. of IEEE
South-eastcon 2008, pp.442–447, 2008.
[4] Gaudettez, B., Hanumaiahx, V., Vrudhulaz, S., Krunz, M. “Optimal Range Assignment in Solar Powered Active Wireless Sensor Networks,” Proc. of 31th Int’l. Conf.
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2354–2362, 2012. [5] ଠా݈ଠ,খྛ݈ଠ,ࢁཬܟ,ยࢁਖ਼ত“ଠཅΤωϧ ΪʔΛར༻ͨ͠ແઢηϯαωοτϫʔΫͷͨΊͷൃిྔ ༧ଌΛ༻͍ͨதܧϊʔυબख๏,”ϞόΠϧίϯϐϡʔ ςΟϯάͱϢϏΩλε௨৴(MBL), 2012-MBL-61, Vol.31, pp.1–8, 2012. [6] Mohr, H., Schopfer, P.ݪஶ, ਅҰ,ۨྮ ຂ ༁, “ ২ੜཧֶ,”γϡϓϦϯΨʔϑΣΞϥʔΫ ౦ژגࣜձࣾ, pp.1–598.1999.
[7] Heinzelman, W.R., Chandrakasan, A., Balakrishnan, H. “Energy-efficient communication protocol for wireless microsensor networks,” Proc. of the 33rd Hawaii Int’l.
Conf. on System Sciences (HICSS 2000), pp.1–10, 2000.
[8] Rahimi, M., Shah, H., Sukhatme, G.S., Heideman, J., Estrin, D. “Studying the Feasibility of Energy Harvesting in a Mobile Sensor Network,” Proc. of the IEEE Int’l.
Conf. on Robotics and Automation (ICRA), pp.19–24,
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[9] NEDO,“ࣹྔσʔλϕʔε”, <http://www.nedo.go.jp/ library/nissharyou.html> (ࢀর 2012-08-21)
