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="390"></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: "dl.acm.org",cType: 'managed',cRay: '92a0a3f7be467a47',cH: 'FX4CG4GD2F7ncMkccE2.tUBuG6QUzSbRyrEcm90p6jA-1743600203-1.2.1.1-2L_TnIV4qfRz.MOfutt1wmZqFj5H1HLWf4DSy6f0xVUrG_j9ylpGIFUdsxUmRbjE',cUPMDTk: "\/doi\/10.1145\/141936.141943?__cf_chl_tk=5SIdGyUFnrbVScAytKk_El3Fo0b1NC97aTVzBrWKdIM-1743600203-1.0.1.1-VAjdbdPjGUK6063Yk0E93sUAP0p79Au.Aum0PGKK5_g",cFPWv: 'b',cITimeS: '1743600203',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/doi\/10.1145\/141936.141943?__cf_chl_f_tk=5SIdGyUFnrbVScAytKk_El3Fo0b1NC97aTVzBrWKdIM-1743600203-1.0.1.1-VAjdbdPjGUK6063Yk0E93sUAP0p79Au.Aum0PGKK5_g",md: "1HCVTizMbMofEYjcgrJQ6jAP5iN973ScbtwekXgsXaY-1743600203-1.2.1.1-udqlU09EtHilYiLltj1_1rSYURLkxJlsUxYje2NNsAHpdmEdFNxb9IHI.O6zyaeYGUKrkYgO8eQ1gaqonolmV3LWsSoeLsqZI89lIaDjJeSFN75HHeJNHXpAEcIPPkzuNzqusIfv6q2t1HFT4qFopc.1Jkun8ZCLoYPZKgUZejbUHCPBStvGavmGtJ_3fhKPDHmJPIVK7qmYPLmVr4EpxE_0W7MF1A9ZRDVNCvTEfF8QGLYz.LzCi_l5CCC09dyQyR48SI0S3apCFhZWzWj2acp21yFiyMec770LaUb7fD08ZWBzCyT3JNAjMKHFswTUwg29MIobL3nhhS6dJdr0Pts0DGrng0V02tUX.ArtgKjMWP0um1lHDyRcc1dcwUfZchvCAYSGU4O4_VPXu0KzYlPzLD0cPztfD50Cdei1vXe4s.Ilnrb4cZ9JTi.LgDj9bDHdpZHhyfiq5NJNiy0OIFoVcHruWMY8rIC3e8OzhRF0BSHbsYHZrwMsDF3Dv8hpqcT03.b.xi4JLXWrOqWlrx9HWuMFT.MucTiA24QAuNaCEBMGDaR7.994cGxBRDZ9Ubye20Y8J8VPoFs87qd30Oi0EeBHPZO70tC7wbzQ8guwqGi.sZymqf0cq7l78M2eV9uUH.xOpwYrKXgG8FDFD2zxU0pwjA3BXYucoTx45o9G5hx641z2cXfJkdAO5pV9Iizrv3q3rJFm1IWbncgkYJ4lTDk_zhh9HiLa08i0NDTHXZQbF0pGPIRNEJlsxEFTE37WBY9izpZESWtgz0kOvF8PiHTu3Lfdd7dWmGbKUs3k3RbbyOg9bbcnJ9QPHAlygg_noWrW4WUbxCkbgvLnSOH0zW2wTCaPGAaCN40XL79r7x.QM2Bp3Yd480IikVNcyFgveK.O2nRScqD.4mt_rAeLJfEPQsVg8exZd2bCyv.4wvKUTqWp4nQnKJDR.fagh3FIH145ENRMSytZOGPgO92bhsaMFl.X_4ZPYAPyYYWRBkBGnV00hMHyikaovspIk3RXZlRsg4k2U8YUFSQhFm5DnvD2fC.t1kvL1kS52M09nKTIRBEPQ3urcBx__5lfDmv7WPfjKKonSIEr1z9lCwi34KZwwJnc0ubQ7cKyuK5n1UNvAXOJEzfaKfNNPmnY0yKFpyqLWog5X0Z3gIVU_S_lWMxvI772hWThJTMwAbfMBV8f693W5JFmqBZnQo_CkOXv4JfqP35YkGjUvC8flEqDI0dcdblKYFGQe5gdjfp_xdHWgAYtv1ExHzgt.SRD",mdrd: "HnaawqdNs0XrE2fJ7cH3pMvZWB92HLGX2SSJmP659eM-1743600203-1.2.1.1-UjesPTDczKbr5AJSqhV6vKZLDBuofQNH61nBR.hRgHRCY5KAS.NhrpndN5qmAqcuzC1iRbSUYKVqtoWVLBjO3ma_dVJJ96eMJremKwha0.xp9aZVlZNcVywYRZaz06_lauyKklLX3spMebWxkTXzHr98uAV3chTjVOW0k3XzFGAtWuxNNG6_AOA3oVD55sR4ND_eT2i4kAVdL2R6ZUn7N.zfovx_w.UV2CLmShry2kwzrKddg5SKBk2qTZQn6ciyJmvzjwr6PZwI1AY_69grQaNv.tnWLamDBP.9IGqDf_MZzlxeLpDe4t4mQ78OlwkRG5B8khH.1ajkHl8zVwHuwF1YVXH4iwHquf_MBs7.86qcDm_ZXtBofK1PeE7QYlN7F_EJ_PMRDlVt4Kty4YGN0tvkk.FIVVSFzQPJ524wcow5eZTvuXJ..LHp0CHSC65Q__tm.otmAamiRz7eErRjX5dZU25ynBdqsi.xRkTaNaHuKTXfyzCE5CJB9YBPgaV4_mHApswCXLQ5uBXInb33iZA6dNsfWUXj24DX2RzsHOo2m6TlwAM74KETyoJ6Rnu0sbIk_S9D_kM8ifltLerER6ALOm3fGxQslYY93DOH9Q4UJhHqHNtvz8CA9vL6lzEB9Exa1TdKzsz5Se4Sg.aoDZGQwfYzxTpvOrBP4fBXFcG3mtv.1XzmsNM3_NkV_yiEXND715kS6xOfrX7iQ4FxWi.p20z5wG.ksQoROHm_nOc8Ng1E6h4UL0vwXLwq_cLcp_Lj7zo01kt7WOb4w8xgVgeVIBEZRUVpLrO0lp48dq17sEO5eK8cSE5FweZ_5H73sywMCQPwcKtcIki_DS5L__TKe9RYObfS2F2JFE9.FWv85hK1HdL1yM2YgVts94I35.YVODZ08qraF6Fhq_3Zljzv0BO1_sOq_dnQrYg_XXtk8QpXAmowk.vWG7uGyU14hqE_BtMrMl0ypG1y9QGiEe99SdMpblZYsLkb_cuhFiH5LlJ6eSPVpk4dx2lXJlclwfF6dYPDgCb.Kgm9esVn7zvOyYqiSFrt7VNKM3efuSDf.GmCfd6BhQuzgWOfB0vuyXwOz7i4HRH6LsnHwt1GtlzMGqn1j9hf.sR1XngXULbxPS_e2OlTviGcQjsWoHa5J5mX2iR3dNUQJVq3mVWlo4CxFUAnK64ejsX8.BJBEqKniV27lO0377raxCJ7mTwyyVnbN1NVVRskruCATQBP9cH.Vv1p52Fq6JdOTNTKSpz83xCbSQIC3YOSSaoPXGPq8qsZQPO4n.hWc60H9bx4xAUalBSQZi2tUxcSD8mtp6_Dn4n9BLoq3KePPFgb.d2hcbKxyP4dh.l.E4OAzIeJAqMTFWJ5I1SacTU4p2IqHcQNym5qyQFTxY4259LZRKlDAsEQCYv21WNasNQCwDrJlX62m2Kqsf9xB0f63c3V0Vx9HIjPR4LoEYHhAaH.E0GGg99n0B.1hHoU2w0cOEc2pD1HOtxoKgfYA_exRxkOM7.GEemQcSTLBefnhZdxc9ckwtkcRsQwL_W2cjSZ9wkeJdgx3Xf2rdCuMOK0xozYomxfkwT63xKN1zfr2dfkZtn5MAE1rcnhEuoGruP.H2PpGl5eKq6yWkXccSwuMOJESCXbTpzpD4VdKvhnlcrWFsEaoXjwtvYkAxgMfEdvM3upklqO1zecf4dQ.bTF9p2EQmjNq89_o4u4wKEizVsN77WivrTEbB80utLZ42mLAgYXRKn3yWAgl8rSHzPgNNkoeRVQ4ejhZWWMGTSQ8HSpN6ro8WlsdOCxfHwFrH_U_JpWCiIrwkCww.DD_MGs5vfL8DCGvXkI.gH460kFQkXtmtiTpchpdjMF5EtXpl2nX_pbK3HspI2dR9xgzmeQ4vS_7dwm3joupWzFqiU8_WgUkqH1tAjU3x07aXH7kMYTzEiDIVZLym.lL9pVCoDEAhUEbJK9h73CBTrXPVYjeN3Ns.eSnDimj7I6KqmLoIplQZtYYpKIUQB5LEMV33ifMfvZ16524plXbLEZah4SqPZoDXkb"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92a0a3f7be467a47';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, "\/doi\/10.1145\/141936.141943?__cf_chl_rt_tk=5SIdGyUFnrbVScAytKk_El3Fo0b1NC97aTVzBrWKdIM-1743600203-1.0.1.1-VAjdbdPjGUK6063Yk0E93sUAP0p79Au.Aum0PGKK5_g" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>