A Novel Weak Signal Detection Method of Electromagnetic LWD Based on a Duffing Oscillator

<table class="figure-group"><tr class="fig-image" id="a"><td><object data="https://static.hindawi.com/articles/js/volume-2018/5847081/figures/5847081.fig.0012a.svgz" name="5847081.fig.0012a" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(a) </b>Strange attractor (<svg height="11.8174pt" id="M151" style="vertical-align:-3.42942pt" version="1.1" viewbox="-0.0498162 -8.38798 49.8592 11.8174" width="49.8592pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M478 372C478 418 458 448 431 448C409 448 389 431 389 410C389 404 391 400 394 395C398 388 406 371 406 348C406 253 308 122 251 51H249C254 122 249 257 231 336C212 421 189 448 159 448C126 448 75 412 23 327L48 306C83 354 103 371 115 371C125 371 134 360 144 334C185 224 192 64 183 -19C146 -100 116 -202 110 -244L125 -261C154 -259 208 -234 222 -220C222 -194 225 -84 235 -23C247 -3 273 36 308 79C379 165 478 288 478 372Z" id="g113-225"></path></g><g transform="matrix(.013,0,0,-0.013,10.148,0)"><path d="M535 323V373H52V323H535ZM535 138V188H52V138H535Z" id="g117-34"></path></g><g transform="matrix(.013,0,0,-0.013,21.411,0)"><path d="M384 0V27C293 34 287 42 287 114V635C232 613 172 594 109 583V559L157 557C201 555 205 550 205 499V114C205 42 199 34 109 27V0H384Z" id="g113-50"></path></g><g transform="matrix(.013,0,0,-0.013,29.826,0)"><path d="M797 0V26C739 32 732 36 732 103V296C732 394 682 449 605 449C576 449 550 437 529 423C504 407 475 389 446 366C425 418 382 449 334 449C303 449 279 437 253 421C222 403 201 385 180 371V452C135 432 85 419 41 411V388C99 379 102 374 102 310V103C102 38 93 32 27 26V0H238V26C189 32 180 38 180 103V338C210 363 250 390 289 390C351 390 377 348 377 275V103C377 37 368 32 306 26V0H520V26C465 32 456 38 456 101V296C456 314 455 326 453 338C491 369 529 390 565 390C628 390 653 345 653 274V107C653 36 642 32 583 26V0H797Z" id="g121-107"></path></g><g transform="matrix(.013,0,0,-0.013,40.473,0)"><path d="M687 650H462V622C543 612 549 605 530 547C498 447 422 252 372 126H370C302 298 229 492 204 563C188 607 191 615 262 622V650H17V622C77 616 93 608 122 534C180 389 262 172 329 -11H360C436 196 541 450 568 516C606 605 619 614 687 622V650Z" id="g121-84"></path></g></svg>)</td></tr><tr class="fig-image" id="b"><td><object data="https://static.hindawi.com/articles/js/volume-2018/5847081/figures/5847081.fig.0012b.svgz" name="5847081.fig.0012b" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(b) </b>Homoclinic orbit (<svg height="11.8174pt" id="M152" style="vertical-align:-3.42942pt" version="1.1" viewbox="-0.0498162 -8.38798 62.386 11.8174" width="62.386pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M478 372C478 418 458 448 431 448C409 448 389 431 389 410C389 404 391 400 394 395C398 388 406 371 406 348C406 253 308 122 251 51H249C254 122 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transform="matrix(.013,0,0,-0.013,42.307,0)"><path d="M797 0V26C739 32 732 36 732 103V296C732 394 682 449 605 449C576 449 550 437 529 423C504 407 475 389 446 366C425 418 382 449 334 449C303 449 279 437 253 421C222 403 201 385 180 371V452C135 432 85 419 41 411V388C99 379 102 374 102 310V103C102 38 93 32 27 26V0H238V26C189 32 180 38 180 103V338C210 363 250 390 289 390C351 390 377 348 377 275V103C377 37 368 32 306 26V0H520V26C465 32 456 38 456 101V296C456 314 455 326 453 338C491 369 529 390 565 390C628 390 653 345 653 274V107C653 36 642 32 583 26V0H797Z" id="g121-107"></path></g><g transform="matrix(.013,0,0,-0.013,52.954,0)"><path d="M687 650H462V622C543 612 549 605 530 547C498 447 422 252 372 126H370C302 298 229 492 204 563C188 607 191 615 262 622V650H17V622C77 616 93 608 122 534C180 389 262 172 329 -11H360C436 196 541 450 568 516C606 605 619 614 687 622V650Z" id="g121-84"></path></g></svg>)</td></tr><tr class="fig-image" id="c"><td><object data="https://static.hindawi.com/articles/js/volume-2018/5847081/figures/5847081.fig.0012c.svgz" name="5847081.fig.0012c" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(c) </b>Bifurcation state (<svg height="11.8174pt" id="M153" style="vertical-align:-3.42942pt" version="1.1" viewbox="-0.0498162 -8.38798 62.386 11.8174" width="62.386pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M478 372C478 418 458 448 431 448C409 448 389 431 389 410C389 404 391 400 394 395C398 388 406 371 406 348C406 253 308 122 251 51H249C254 122 249 257 231 336C212 421 189 448 159 448C126 448 75 412 23 327L48 306C83 354 103 371 115 371C125 371 134 360 144 334C185 224 192 64 183 -19C146 -100 116 -202 110 -244L125 -261C154 -259 208 -234 222 -220C222 -194 225 -84 235 -23C247 -3 273 36 308 79C379 165 478 288 478 372Z" id="g113-225"></path></g><g transform="matrix(.013,0,0,-0.013,10.148,0)"><path d="M535 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class="fig-caption"><td><b>(d) </b>Chaotic state (<svg height="11.8174pt" id="M154" style="vertical-align:-3.42942pt" version="1.1" viewbox="-0.0498162 -8.38798 62.386 11.8174" width="62.386pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M478 372C478 418 458 448 431 448C409 448 389 431 389 410C389 404 391 400 394 395C398 388 406 371 406 348C406 253 308 122 251 51H249C254 122 249 257 231 336C212 421 189 448 159 448C126 448 75 412 23 327L48 306C83 354 103 371 115 371C125 371 134 360 144 334C185 224 192 64 183 -19C146 -100 116 -202 110 -244L125 -261C154 -259 208 -234 222 -220C222 -194 225 -84 235 -23C247 -3 273 36 308 79C379 165 478 288 478 372Z" id="g113-225"></path></g><g transform="matrix(.013,0,0,-0.013,10.148,0)"><path d="M535 323V373H52V323H535ZM535 138V188H52V138H535Z" id="g117-34"></path></g><g transform="matrix(.013,0,0,-0.013,21.411,0)"><path d="M447 623H65C61 580 56 530 47 475H76C100 541 106 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180 103V338C210 363 250 390 289 390C351 390 377 348 377 275V103C377 37 368 32 306 26V0H520V26C465 32 456 38 456 101V296C456 314 455 326 453 338C491 369 529 390 565 390C628 390 653 345 653 274V107C653 36 642 32 583 26V0H797Z" id="g121-107"></path></g><g transform="matrix(.013,0,0,-0.013,52.955,0)"><path d="M687 650H462V622C543 612 549 605 530 547C498 447 422 252 372 126H370C302 298 229 492 204 563C188 607 191 615 262 622V650H17V622C77 616 93 608 122 534C180 389 262 172 329 -11H360C436 196 541 450 568 516C606 605 619 614 687 622V650Z" id="g121-84"></path></g></svg>)</td></tr><tr class="fig-image" id="e"><td><object data="https://static.hindawi.com/articles/js/volume-2018/5847081/figures/5847081.fig.0012e.svgz" name="5847081.fig.0012e" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(e) </b>Critical chaotic state (<svg height="11.8174pt" id="M155" style="vertical-align:-3.42942pt" version="1.1" viewbox="-0.0498162 -8.38798 84.1513 11.8174" width="84.1513pt" 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id="g121-107"></path></g><g transform="matrix(.013,0,0,-0.013,74.644,0)"><path d="M687 650H462V622C543 612 549 605 530 547C498 447 422 252 372 126H370C302 298 229 492 204 563C188 607 191 615 262 622V650H17V622C77 616 93 608 122 534C180 389 262 172 329 -11H360C436 196 541 450 568 516C606 605 619 614 687 622V650Z" id="g121-84"></path></g></svg>)</td></tr><tr class="fig-image" id="f"><td><object data="https://static.hindawi.com/articles/js/volume-2018/5847081/figures/5847081.fig.0012f.svgz" name="5847081.fig.0012f" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(f) </b>Large-scale periodic state (<svg height="11.8174pt" id="M156" style="vertical-align:-3.42942pt" version="1.1" viewbox="-0.0498162 -8.38798 90.4147 11.8174" width="90.4147pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M478 372C478 418 458 448 431 448C409 448 389 431 389 410C389 404 391 400 394 395C398 388 406 371 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<div>Simulated Duffing oscillator circuit phase state.</div>

Journal of Sensors

fig12

Figure 12

Figure 12: A Novel Weak Signal Detection Method of Electromagnetic LWD Based on a Duffing Oscillator 