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    <import namespace="http://fasb.org/us-gaap/2021-01-31" schemaLocation="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd" />
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    <import namespace="http://xbrl.sec.gov/country/2021" schemaLocation="https://xbrl.sec.gov/country/2021/country-2021.xsd" />
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    <element id="ALRT_ExercisePrices" name="ExercisePrices" nillable="true" xbrli:periodType="duration" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_IntrinsicValue" name="IntrinsicValue" nillable="true" xbrli:periodType="duration" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_Total" name="Total" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_RelatedPartyTransactionIncludedWithinInterestExpense" name="RelatedPartyTransactionIncludedWithinInterestExpense" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_InterestExpenseOnPromissoryNotesIssuedToRelativesOfChairmanAndChiefExecutiveOfficerOfCompany" name="InterestExpenseOnPromissoryNotesIssuedToRelativesOfChairmanAndChiefExecutiveOfficerOfCompany" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_InterestExpenseOnLinesOfCreditPayableToChairmanAndChiefExecutiveOfficerOfCompanyAndHisSpouse" name="InterestExpenseOnLinesOfCreditPayableToChairmanAndChiefExecutiveOfficerOfCompanyAndHisSpouse" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_InterestExpenseRelatedToModificationOfStockOptionsHeldByChairmanAndChiefExecutiveOfficerOfCompanyAndHisSpouseRelatedToFinancingProvided" name="InterestExpenseRelatedToModificationOfStockOptionsHeldByChairmanAndChiefExecutiveOfficerOfCompanyAndHisSpouseRelatedToFinancingProvided" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_InterestExpenseRelatedToStockOptionsGrantedToSpouseOfChairmanAndChiefExecutiveOfficerOfCompanyRelatedToIncreaseOfBorrowingLimitOfLineOfCredit" name="InterestExpenseRelatedToStockOptionsGrantedToSpouseOfChairmanAndChiefExecutiveOfficerOfCompanyRelatedToIncreaseOfBorrowingLimitOfLineOfCredit" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_RelatedPartyTransactionsIncludingWithinSellingGeneralAndAdministrationExpenses" name="RelatedPartyTransactionsIncludingWithinSellingGeneralAndAdministrationExpenses" abstract="true" nillable="true" xbrli:periodType="duration" type="xbrli:stringItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_ConsultingFeesToChairmanAndChiefExecutiveOfficerOfCompanyAccruedOnLineOfCreditAvailableToCompany" name="ConsultingFeesToChairmanAndChiefExecutiveOfficerOfCompanyAccruedOnLineOfCreditAvailableToCompany" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_SalaryForServicesAsVpCorporateAndDirectorOfSingaporeSubsidiaryToSpouseOfChairmanAndChiefExecutiveOfficerOfCompany" name="SalaryForServicesAsVpCorporateAndDirectorOfSingaporeSubsidiaryToSpouseOfChairmanAndChiefExecutiveOfficerOfCompany" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_RentPaidToCompanyControlledBySpouseOfChairmanAndImmediateFamilyMembers" name="RentPaidToCompanyControlledBySpouseOfChairmanAndImmediateFamilyMembers" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_StockOptionsGrantedToMemberOfBoardOfDirectorsOfCompany" name="StockOptionsGrantedToMemberOfBoardOfDirectorsOfCompany" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_LossOnSettlementOfDebtToRelativeOfChairmanAndChiefExecutiveOfficerOfCompany" name="LossOnSettlementOfDebtToRelativeOfChairmanAndChiefExecutiveOfficerOfCompany" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_NondeductibleInterestExpense" name="NondeductibleInterestExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_ExpiryOfTaxCredits" name="ExpiryOfTaxCredits" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_TrueUpOfPriorYearBalances" name="TrueUpOfPriorYearBalances" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_CommonStockIssuedToRetireAccountsPayable" name="CommonStockIssuedToRetireAccountsPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_CommonStockIssuedToRetireInterestPayable" name="CommonStockIssuedToRetireInterestPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_CommonStockIssuedToRetirePromissoryNotesPayable" name="CommonStockIssuedToRetirePromissoryNotesPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
    <element id="ALRT_CommonStockIssuedToRetireLineOfCreditPayable" name="CommonStockIssuedToRetireLineOfCreditPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" />
</schema>
</XBRL>
