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: '91351076bf3237b5',cH: 'nBpR4K0fG8e_6U9UjH8QNJWNk0Ys6k8gEBw3wZf1dBU-1739787830-1.2.1.1-tfYb.qRDstDYLy6uWeXAh44i15RWCl00ryCG01.n2iH8D1dzZWPAvLhNDqrGaiQv',cUPMDTk: "\/search?q=VOSviewer&__cf_chl_tk=BL0RxlLA.d2BQsDzlFF7rLGHXQRX3NJ8sI112stMDr8-1739787830-1.0.1.1-13MJylo8EKHnR_dnIGlkxDxmf73A18ZG2CC2EZWt.a0",cFPWv: 'b',cITimeS: '1739787830',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/search?q=VOSviewer&__cf_chl_f_tk=BL0RxlLA.d2BQsDzlFF7rLGHXQRX3NJ8sI112stMDr8-1739787830-1.0.1.1-13MJylo8EKHnR_dnIGlkxDxmf73A18ZG2CC2EZWt.a0",md: "7cOARlEmTFV8blST5qOnXRDT1K8kVW8t4P0e6WCaGkU-1739787830-1.2.1.1-5qPTM1tEwmEHZ.27xfmkVyqAsWC.GTso2aTay5xalNCNT_Jf1cc0leZAR36LTEW.4hEcA1YfiE2gczA8s_X5LJzQ.gLbYuEmS05sif6UQrTXd.5JYGG4GMzxmLYuReG_N0mqDPTzeofOf3YxWtmX7CCvO02Tr3UYQQ_eM3fh3mWLeJWXdkL0VWFwJ9vECeGgk4N1a8fRUaIC9f_mdpnXd.3oieXWctTkWZjKUWtLBB4haXVxjhitAgEEnoSBLBI8vus4fS25To_JbgdVFUned2gfzAngyLMxXnwU3kUEwJaF79FCwjWEbG0rJVZKOh6z8Wae9IWQ5iVkSCyJ6kEK42mdeL9zj2e0IYbYQH4I9fOWhrwW.Pb_xtRxGC8Xdtt8oNZcmdFJiPHPCeZo44G2CArpF.GH07I1cKhGbXpl1YH0Keu8GRifvO2alRZT.ZLSPmgLIE2ENIy9RIGIL70M1mffc6HTFxbBGsUkUb8VqjdsDyXbRAJSKpXDzJZwN6ZaDJpOOr2WV2a5_6foki6gHQtUUop2uXAgD.mKjtWH92CZu8EAVM.xvT58f4NnEVB785McjzS5leywYUZxmxiGWh4bN3oXzhyq3QXTWvVpOcts48y8PsiFgOXl3pvYCAmoPcpFRidz_2MHMQuIUX7TlhhO_kA7LCBZ8KVHEMnHbiC0.1p3hUTJlhWFTK7csQkWVmBxS0tX9MRxl4wDAI6Wg8wvz2fRaUBGHCtjmDk2n.RHIqlc_IJbH.kmBpm5cgRS1n2wm7WnmE4tSfctaQz1Tx6U7nUjr0rZKDNVm4DAKItvUbGDpFGRWyUOCqpWthHlr065l_1AX_HqC6.9VMbaV7rHfKGdn6cN.bwedm_zCNk5.lOtVWaPJ8CWpE.11mTSVTYBWoKc9cD1j4exFDXk0vPwpwAtihMT3.OOiQzS5215v_JZTc0PahbPr436PjfKng.5iF0vcP4kGglN1zntwKDhtWH4yoT_pCorSCGR2yq8h2JgxG_eIHZ4ZStz9QiWawAJp_8SjkQqwyZIkJJbLCZr7Z5JKidSWkHbNpmvCE3IIpmWagBrkbwOBOCMnu11Kztw0qQ8Y3U_5qKGuBVJRrmEEzvi5tCPsF08l6qKhq6GgASe8MahMNNg2nLmcpL_wcfgs0tU_kpQ8xNOBSzJp4jdSkRelUT8oFk6ZiX_ga_a7cFK0mYEjZMOFV7BGpveE6RBTccnKthl6kHU.5Jfp6jm_jBRWML5kHkA4k17YV77zuPloYYi6WSJdVjd1Xu9bCEAyoNlBGoIyYiU0wEBgYvCabVVMp_kx4JxMEL0Ip_9W7Q1v5MF7fWzctxvOu2evvKESkOz6w05Syg4Y3qmMN0LYLb.ZRhjLBv4AETgvOsK9ZNwXOGDdOAI7rGnF.MTC_nv25O16BF.UlMzWt71wy5UWMNVjUF5ZeRKkcWDkCa5UMWMX1.EIRVk5aSCKhWHAEaX5mgXCSPKMO4pBnGhqFIa8.q55BLWd6sZFhMNM02opxTKMQD7t7wwdWSYLsJdpkDJl2v3eK51POGQ6UaNX9HY1j9pEtCiigIz7MEuUR102xkzPwKPLhotXol8pemjWxoWtbdnHJ1qCLBC6bjdmaV7Gw.WKE2ltS5obmCo7pEVoTnNz50Tk5hM.oGWRkR3m59.WFwRaZ7VkDni9SbZeFGpGgKFrnK_jfBz0T.9P6jJ8GMz61v4UDGFfGCneyqjiZNDd9PyB6znDbQvaWmfHN.D9xriUY4sCSDUpUhGiDZZLOLIuFOhIcCiyCDfNPDl54NJy0hdLsTfe7uU9EwACtfq6JMw4RtBQkETbaqeUs7sjv6TBXU43yBhYrmccy6geWhRWA_m166h7D22g7G78rcZEiDDm3z9KTan34FSlJlayvylZ.NlTRA7ndx9vjAF",mdrd: "fRXXlxRInV7F4sVe7bNT2JlbvPhumotksoPoXdXQ2Qo-1739787830-1.2.1.1-Mei8FTde0PdCQd4sFU4ndKeSGj2cSCXECk593WGyayOm3kXqPLceKK3oClPY9SO3nbA7SLfnwxLCljL7xJJu26U7tHWW_pr7lqTQ9agHWJXp6A2D3Z08tLHRKb8GNBN0qNkrGS8ZWSPnGzmfyKKvahSrHgTXB7PbHMvsS9yLRe1n7625Kq7pBlldwr24z7sQVrjkzVp638CPXgQxtDCo86ElfRp_HwdS5LqxvMDINja40Q58KzgGJDXc_PCodc8q9ayvbkY0usDBnVqmerGGrohMVtybKZBMQ9e4_zCw.u4NN3ysjDRxeswKt09q2EH7tjRmAXp.cmuQmBoKX3_rTXIfRl.5yitBqKF6LmuwKoLVAY49dN_J9iyz3K9hIS7dPhtVglnXIjtIHmpcKVIkl3twPImCOVsSiTrLAHP0JZdnNyeA2nqEr9H3gZl4d10aF13RVPQnvf_cs9wfeev9o2VBHB69Us6eLYJ3xntz7qXi4eY_6.IV_RipdgT0SPEn04LExMq5Mnj1mBwgiiOOLncTnLwmFjwkx5SnwhDlDjU2KzaiWoc.3cpgGCbvryr5_XE4HNZbEt1_EqJCPGq67CWgkEzBcoizE9_AI0tdvcRI4rQzSTcq21o5XxbDG0WJSxvgyb.qzkj9fLvVdrfoALSjWsfRGHH7efcMG1dvQVu8Ylye5LvBh0_sgjnGTNCsqB6tEsFOopvCZTd0YBTIVDBx0ptou2gbQ_xtir1bhX9Iyaor5BTuv3DbweGIUp2d8TTGVSv147j.xs4seTinixPHDAwYGzYshX.WVfC.jpJzRxCVLcONUkqV84zyPPgl.ivxNDVKHW3yr2pptBZ.rT14QUGOJOrRY_Oxyh12nTqNP.Y.qWr8LnEFeShIxzxB7cia68usZaNeE1nITWadgDEVB3lPIAvgpgJBfm9a.DbjUAi8.UrvdMwwJmW240.v9gT0SLYZw.yxmK7InWpi1tUX96Ky_6gIcaQAqmio0FV8QGFAINWIJLTC.qalPidW40eobN2Ohc5r5MaLDh4HxmYzpAn5f3Akw3cj7yAWQNlXpr2KrN7MVUhlo.SBuQbPZL7VsY.Jeo6yjnscbh57DDxKC1Am_Urbabr2X39JhbXU6I.P9ntq.7VPoZpCIz.T0e5.upS5bw4JBdL8NgbQHiP1Nft_0bF4ICzc8eeuKQvMNOk2uqUHen062IZIJ3pmW6L2ucTIfSkMKrEWR4XZQfwET46Y2zlG4PyM_IeHbNfgtr7GFSIwCRuGlH.5Tz.HHItaTDKl2YDjcfTYbl2AhU4Jc95ITAHPDouzDqz_5OAPw205y6mTLRNiChV0K2BjKCTHdEjgA6nST3WCBnhscmmDoP57spVl1GFSePrp68syZB7U1uW72KLursKfDscWG.LuSZ0Uw10Pca59QQZKsxOTuiST1ud_qPvB65a8FcelYcfhUFKqYenOolVMk9.goITc0ZmmE9UPkhg7qKlN1NGcmZHYCY98ut8W6DviMGzCtJnq1zStNrbr0exNJGBXGMZtZwZCodLt702KcJwaMwuA.fsW9O6tkYA.byUTk_X5Rq.Rnz3R71MU2mEjgXEIvujm.aSZk.TcB8PGUAdAWW5ntR1LcscKzd1Y6E0XzanhBSMyH_HqS8vMvDUqGPEBekFJ3D_Yfttxv1L64qbo5BAWTowEOm5AnCwfK1TbgN7SNk8gH55moyFC_SIoxkrtcXLYIWwgulfGgL0yn4Tz8PSrip0OvQ29k9o6C_e0ZTqAuF4Z5AHGmqppgEJOfBBatTy43uX4afD2CAP46x7hQUrPVYAoelwYTdPYXqqTadiKrjRjwXWPEugkqKyOYKjM3D1TUzvYYUgFaIDpvb5SWtEUIFOLlUzA0aUYglXIUhgMHSW9XlJDDnmRaayuqSoT3pCzA0svRWzcWFZa6XOT4Iixp1Ph_XGt9Ojm1TAm_wrP.OUYkIVYWq9qK58DS0N3"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=91351076bf3237b5';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, "\/search?q=VOSviewer&__cf_chl_rt_tk=BL0RxlLA.d2BQsDzlFF7rLGHXQRX3NJ8sI112stMDr8-1739787830-1.0.1.1-13MJylo8EKHnR_dnIGlkxDxmf73A18ZG2CC2EZWt.a0" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>