CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="120"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'non-interactive',cRay: '914c63afcc26fd96',cH: 'qT2B_w5YnPLurR3TYnP1Foybm4FtCAFScxoppts9mZo-1740032412-1.2.1.1-XK94QxJRW_wSKS2XiCgFeHBcXiQd_Fi4KQnV8N3a_9KHBq70faCTxkOSDT5KRjhs',cUPMDTk: "\/abstracts\/search?q=douglas%20metric&__cf_chl_tk=BSC_2BG_e.ELwG.fUdz8HoUeQMhz7qs6YVLyDU.CKaw-1740032412-1.0.1.1-30.BnnY0.ft2p3KIvnLNT1yeinM5BB9Wf_v0z4P9U.w",cFPWv: 'g',cITimeS: '1740032412',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported-browser",fa: "\/abstracts\/search?q=douglas%20metric&__cf_chl_f_tk=BSC_2BG_e.ELwG.fUdz8HoUeQMhz7qs6YVLyDU.CKaw-1740032412-1.0.1.1-30.BnnY0.ft2p3KIvnLNT1yeinM5BB9Wf_v0z4P9U.w",md: "If336z1xqwFcX9o8B3jYQJwklHoHNeuj.yFiPvYs6aE-1740032412-1.2.1.1-VnIG0eHuqmwGZw9iXi8pWlUbLjljyJcs.XNpG0OZIAnB3rkY9.Waw34_9hHIChBdA16fV8DDr4kjfj.4YR6LJDheghGmkFkwsGaj1lRBpNtAhi5O.n8jrfyGk.XAlqiD1.JuNCxc8jxpbr8h9p2opxesmAo30jK8zOcm2Qw6d9bvOC5ZhMWC5i6oUx0xCZkRNaxIpOZ7LZi8Q8Ydr9842RC5uBEDG83xlCpRpZl4rzfUNgMQIkSQcvPxwflUZq5Iy8AoUBrpz8VC9wFa1y0B8RDdprhzuqQUTKWCQILRXbG7I2Qr55TDpvSbecdidjSNnTd2QcEVphCw7QkOsLQL5AtyfXLh1YFrjxvgMNqbMLTVdfkvNXko4Um85fc3ZDReFkAt0sdiIuOa978lW6V5P9vd.S58.iwLo_9nXqOhNxB5bwFW_M6Evo99.uORpVWrZkTMWkb0bxSCRDe.vU1RUBCRgFJsgdxLksC1POFWjXMtkIsApR9NlkPghBGPbGQ2hTSK6xg9Y.XyOS79o_Kq7dtIe6ZpCNTY5VUkvDt0pSNvNoGZUy_3.gA9Ip2EEKxrFpYjS9tjx3hOUPiq.49.rFAZeoyXpIm22KRMeDK2A13CWXVmK0I5OIZWuRVf2IHg_eU.zg01s3gFDerXkcB8Al7LYdNQNs33O8TZ61uMGNtVCnAOwIIsgN846FKfsutN2aSZz0g6gVfN2FbrFDva.KCMgQgJxIOSLGzfZUqORQ2YzoH3FvStFKURKYR1flRBi87XEcxe5fqsqy0nHbKKxFfbdS6ZTldrQvPV1Tr6NtZKcOICndq2HctITC0rzX7CT0yTfFfccrOfKB1CyeJ3kQ_M.MNgmpzJDWoD3Yx7LPB6qxDy1kixZZo3tpegYysI4ProB3qwMFKXF2grNIQktn_LwfXs_nug6_7KxNCM7U7kmliQli9HhxBPjCjC5nWmp9BLtD9tNkARhIl4jGYJlAMvYJtq4Z8y7ym5gqSWXX0Sgsc2xZ617CnqoiCKJSyJ2e8m25MtBJmpPld3p_GufWW08UtcNi4FS9JlYg7LG9_Ct7Sr5chRxCaDiqB67UKV.jpcpkLXDJi8wopSAAC2JwlHXo2fv1ugBIPyELFGe4AwlFBIqvIxruPRmn31D1zLS5_s7u0z83NnYCx.2saVIxieJHPoE4LKO5rcyZ5h_wF0U4NuioZJU5TdCcag2aQizQpwpBj1CM7Y9ftBfHcMfzXNr2GJeVfzLgTys.tbyEPKcgQPL.t7viq0yAjTT2b73DImeJrmh1up2HZfD5fPN1yAKmQhz_ndzi7tCU7PtPn3YQk_9wiSfwpAXkJOeJbJ_99PI7m4m5DidKoMuZ0Cag_FbvxFMHV1s2OaEPDzD7UL_KetEsT0urrejSMeF3ZJDPMB3SSDggcNxWEdWO77o0IPnTd04GzZTK_ATPLKdBq0rlyr_bEMERQkXAIl2xH3w2pVBH3PtSKfk_8fcMcWirB.HHMvSxaoqAZV_WCKH7DG7mwd5Z4fCtS6zg_7k0RMAz2FRi1t8siHa8_eCQvGNPjgctph3bpFd9p2EeeaK9LTJqOz_oeMQh5FWGQY8iG7_8V7KYC78KLRrlrTt6vS4AZFZswis9ENf5RrITDlM4QoOjl.AziZZkt3tIxXTEbzLjzmcrOIVcS2ppcjYPWmS_n3eM0DgWTdnW6vh7GKmGNDrmFZNJ8z_blcuUnzZmFbrjNsTCyXIDXthvOtdL89qLEjhhvDR273M7KR7YO4mne.nIXl_n6uybTvSQ0jR.w_Mt19QD1fT0YopLXqSabm8Wviu2tjBzJyLTJY_KrPLF8c_Nrmlq81ffQP63CzToIMyyPCT8ZoGtUIx7NMsLiZ8u5Fv76XVYsiBNUUtXwzFsf1F2X96kDapiP6X9riPVlUEuqfbMqmEvbZXvAaFaW8tg1KTDonvW3tt3J5ZtxviB8",mdrd: "FQlKTHul.__JgEnI2.r9SMI8PgWya9Yp61SFcxU._28-1740032412-1.2.1.1-MrvQQp18nFwJC5fYq98UJeIrLNJV3FFncWNAMlbDeHzw8hBkN6EyiNyrmwNY6E.agRD1JYZexsXhiERZFJISLcvx6QBCymyi8HhAPrHXgTEAQCT.jHtOUhpd6CgiyHrRbeiPDEjpnaP6h1lgsCjho6nvK8twx0RBas1qTzU0o_jpKGojfc3y8RwgI96HVGe7tfo6iqbX0.ZWLPeZYeyhlKRPm5LSvkEgY.XRpw1gpZnmJmkzObe67NDiMRcAYSiCVcdhyXxlcxvX2WRB0gLAu2V7zWziwBLAxrttOZ4Dl3BLUgLBb7LbVlxwQVJgJb7ePk6UhCXItDhVtQOmxj4UvpjfOnWVvR4JUYMGlkX53TtYqf7.X9Ipptj6LXDW7A9lXe5hb6_kB2Zjsxq1a8jq7wGuUnAjxopGUA.hCKl2X6fR0ttFeh_py1oXz4PeeX71j8UX_SpIJ1EOdIyLL59S_OjJAaSMo5GMEEjj1JGLSednSYscjevwgWhv82TDoQzHHPdiADsps8fCdfvBiuiYW.Z4YcJ1GgYLEhwpf1Z4otn1X2rogIrLCtOtfIk8LKYMGH3YGRyYMB2CGLzj.XKlpf4tPaJoNVh4zoOi5r0X8VZ3lAdJCnFNimcTMkEwJhqwdWciDEWDhX59vPHztkYfiMb7lh4S667Brd97YKpB5NLF_8uryF6ngaDwqXjuRB8N5I0qB.WUF6z3KBjysito5dKXrT.Lc9qDmkzPipvppBq5U_Z9tZ9R__dZcwD_g2o1PT27Mxh4cNyYd8C6kYqSIcW4uvqgSBxzutBIhoVl265PAuZORdlZRzQKoa2rHxekrQf4BcXd0XAFVI2aLJ2UMciQxdpslmqrjMVDrb4iXVk__SfGpRDTAv06u50_FbwhonLmX73GuRsv3pFW4whKgT_CI03vKio4dJUKWAuy5R8GKDYOhJ.i3bTLOVx6Si0uCQQIPy610j0F974ozs02vDM6qBUo9TJLW2NevA6YqfMA0bg3b8B.A9QLc15Jpn8RIW7dTyYnGFdoITRKl.Lflh1IGR_ah5WjgcIGBPqnavMwBNnPrxCOK3zneWMGRFfAc8BhVmNhZ9InYmpHLvGpGJR0rovvm.2gjKrTonz0ti9.wgcygSevegoAoouLo6lZxydwN6X0Sg3IoG37zwvLpSF19u3A3kPGB0ptBJa8EylwnQAl3XovAW9qBPNQaaNMGLU5WS2wRwuxaZzQkEkTAwa6fBEWPx69Z8bCwqvE.GFYt3JEux72wwfC4iuoMVC5FVw3EbMG3NMWm_LvAPtqCbEhNLn1P4rZmHZGdnjsbwJIfwdBNS.U4cSAee_sNFGqcG93HQ6KuWY4LZqJn5OdwmNqNyW463Lle8rq9oR.D74Gtc_BXr.u8Q2gGtcnt0WcU5OZAIX.jfLcht6doSqx6veYJ8.coKpmhelXb_MejGb8hhdq5qtGjhJXXornTQ19WrfpJ7hPcHTQjEWEsgFfgfNWRTpV.kU0xiptSbB7eZm5_Mzv1IcbrMTSPzTjfY.xXioTmKCsRAZFhnMi6DTG9xnPJ6OH68i3Y2u6ogq8n4pdSdbA3NNxozXfxHhBCS0nvYMfUVNjzISfoDO3DMPccafAILH.e8LNOSIiDei7gVbT23yCGOlaf36ZMLupobaPcd_G_39zxwtFg8PCHDpXKeK4jpGJ7HLK2yuUGWPm89LvKk8XjouSZFSaYWV.7Xp8B_Ozdig2ECV5WtMhhV93576JZKksPxrslUuhtFXdzvTnujI4bNgQHehpBHVoTEKJ2ocBW4pUUucn8gm7xSXMj5oN67KWE9KXGgcNOlpv1s66Nys7qBEFKC.9RVFCo8785dxTTYCWn13wGs3lApIba6Ubpq2u7Yl0hP9pr8OxyR7ksq6uVAbwH4HV3.aNwwup6N4jNPpTZYcYy8G6tWdyr9ERUCvopbUHVjgVLcayLQzcPV_7xkPdS7OdtcpdFJ4DK5Osyn1Ys_RLiSkqGu27eQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=914c63afcc26fd96';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/abstracts\/search?q=douglas%20metric&__cf_chl_rt_tk=BSC_2BG_e.ELwG.fUdz8HoUeQMhz7qs6YVLyDU.CKaw-1740032412-1.0.1.1-30.BnnY0.ft2p3KIvnLNT1yeinM5BB9Wf_v0z4P9U.w" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>