• 제목/요약/키워드: Flow Exit

검색결과 988건 처리시간 0.028초

소형차 전용터널 내 수소연료전지차 화재시 집중배기방식의 제연성능에 관한 연구 (A study on the smoke control performance of the damper exhaust system at FCEV fire in tunnel for small vehicles)

  • 홍서희;백두산
    • 한국터널지하공간학회 논문집
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    • 제24권6호
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    • pp.745-756
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    • 2022
  • 도로터널은 입구와 출구를 제외한 모든 면이 막혀있는 반밀폐공간으로 화재가 발생할 경우 화재 연기는 화재로 인한 열부력과 터널 내 상시 존재하는 기류에 의해 종방향으로 확산하게 된다. 이러한 문제를 해결하기 위해 도로터널에는 연기의 이동방향을 제어하거나 화재지점에서 직접 배연함으로써 안전한 대피환경을 확보하고 신속한 구조 및 소화 활동을 위해 제연 설비를 설치하고 있다. 도심지에서는 인구 증가에 따른 교통량 증가로 인해 도심지 도로의 서비스 수준이 저하되어 극심한 정체현상이 빗어지고 있으며, 이에 대한 해결방안으로 도심지에 지하도로의 건설이 증가하고 있는 추세이다. 수소연료전지차(FCEV)의 TPRD를 통한 수소 누출 시 화재가 발생하는 경우, 화재강도는 누출량에 의존하며, 최대 화재강도는 TPRD의 오리피스 직경에 따라 달라진다. 본 연구에서는 TPRD의 오리피스 직경 1.8 mm를 고려하여 최대 화재강도가 15 MW일 때, 소형차전용터널 내 차도 풍속과 대배기구의 개방 간격에 따른 화재연기의 확산거리에 대해 분석하였다. 그 결과, 터널 내 차도 풍속이 1.25 m/s 이하인 경우 터널 내 기류제어가 가능하였으며, 댐퍼 간격이 50 m, 100 m 인 경우 화재로부터 200 m 범위 이내에서 제연이 가능한 것으로 분석됐다.

카메라트래핑을 활용한 광교신도시 내 도시형 생태통로 모니터링 (Monitoring Urban Ecological corridors in Gwanggyo New Town Using Camera Trapping)

  • 박일수;김휘문;김성열;박찬;송원경
    • 한국환경복원기술학회지
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    • 제24권1호
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    • pp.69-80
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    • 2021
  • The new town in Korea, developed as a large-scale housing plan, has created urban ecological corridors to provide habitat and movement routes to wildlife and to promote natural ecological flow. This study aimed to investigate the use of wildlife in 10 ecological corridors in Gwanggyo New Town through camera trap technology and confirm effectiveness by identifying environmental factors affecting the use of wildlife's urban ecological corridors. Our researchers installed 20 unmanned sensor cameras at each the entrance and exit of the ecological corridors, and monitored urban wildlife for 10 weeks. According to the monioring results, the main species in Gwanggyo New Town were identified not only raccons, cats, water deer, korean hare and avain but also magpies, dove, eurasian tree sparrow, ring-necked pheasant, and eurasian jay. The number of uses ecological corridors of urban residents was 801(13.49%), as high as that of urban wildlife (1,140, 19.20%), which was judged to have disturbed the use of ecological corridors by wildlife. However, most dominant species of urban wildlife are nocturnal so that, it was judged that they share home range with urban residents at a time interval. In addition, according to the correlation analysis results between the mammal using rate of the urban ecological corridors and environmental factors(ecological corridor-specific length, ecological corridor-specific width, cover degree, shielding degree, connected green area, separation of movement routes, and presence of streetlights), environmental factors were not statistically significant. However, the more the area of green space connected to ecological corridors, the more increasing the mammal using rate of ecological corridor(r=0.71, p<0.05). Therefore, the area of green space connected to the ecological corridors that is associated with rate of wildlife using corridors should be considered as a priority when developing an urban ecological corridors. In the future, this study will extend the observation period of the ecological corridors and continuously accumulate data by adding the number of observation cameras. Furthermore, it is expected that the results of this study can be used as basic data for the standards for urban ecological corridors installation.

사례분석을 통한 공동주택 하자담보책임 종료 절차연구 (A Study on the End of Defects Liability Exit Procedure in Apartment Buildings through Case Studies)

  • 김진국;방홍순;최병주;김옥규
    • 대한건축학회논문집:계획계
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    • 제34권10호
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    • pp.25-32
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    • 2018
  • The ending of the warranty under the current Multi-Housing Management Act has a lot of problem as it is very disadvantageous to the business entity and it makes hard for the contractor to finish the repair work. It is almost none for the business entity to get the written confirmation of the expiration of warranty liability from the client even though it sincerely completed their warranty obligation. It is because the client asks for the works other than fair repair arising from the defect in the work, such as the upgrade work for the enhancement of the value of their assets and the repair work which the client should take care before it issues the written confirmation of the expiration of warranty liability to the contractor. "So, though there is the law specifying this matter, the parties are relying on the unnecessary civil agreement. This leads to the big social and economic losses. If there is no agreement made between the client and the contractor, that leads to the legal dispute. This research on cases of 10 apartments shows that the types of works which the apartment residents ask for depend on the characteristics and conditions of the apartments and that they ask for various kinds of compensational works. In addition, it was found that there were many cases in which even the civil agreement is not recognized as the ending of the warranty obligation even if the proper procedure is taken for the ending of warranty by the contractor or business entity. If the collateral is to be offered to the client, the contractor would get more hard because there is the additional cost other than the warranty obligation, thus damaging the legal objective of the laws trying to minimize the damage made to the resident of the apartments. It means that the increase in the unnecessary warranty cost would lead to the increase in the selling price of apartment and the ending of the dispute through the civil procedure would make the Multi-Housing Act ineffective.

양상선(楊上善)의 삼음삼양(三陰三陽) 학설(學說)에 대한 연구 - 음양속성(陰陽屬性), 관합추(關闔樞), 기혈다소(氣血多少)를 중심으로 - (A Study of Yangshangsun(楊上善)'s theory of three-yum and three-yang(三陰三陽) - focus on attribute of three-yum and three-yang(三陰三陽), the bolt-leaf-hanges(關闔樞) theory, large of small of gi-blood(氣血多少))

  • 이용범
    • 대한한의학원전학회지
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    • 제10권
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    • pp.450-493
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    • 1997
  • Three-yum and three-yang(三陰三陽) is the change state of yum-yang(陰陽) which is caused by six gi(六氣). They mean the flow of six gi(六氣) which exist throughout the viscera, the channel(經絡), and the skin. But it is not easy to understand the meaning because the contents of the attribute of three-yum and three-yang(三陰三陽), the bolt-leaf-hanges(關闔樞) theory and large or small of gi-blood(氣血多少) which is the main clue that explain it in ${\ll}$Somun(素問)${\gg}$ and ${\ll}$Yeongchu(靈樞)${\gg}$ don't coincide with each other. I, the writer, tried to understand the uncertain meaning and the contents which are written about three points above differently in each of the books that are ${\ll}$Somun(素問)${\gg}$ and ${\ll}$Yeongchu(靈樞)${\gg}$. So, from that the course that the book, ${\ll}$Huangjenegeong(黃帝內經)${\gg}$ is handed down is so relatively simple in a wood block-printed book, that the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ has less wong-words than the Somun(素問) and the Yeongchu(靈樞), and from that Yangshangsun(楊上善) wrote the note in the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ by royal order about 100 years former than Wangbing(王氷), as making projects of Yangshangsun(楊上善)'s note and the original of the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ which has relation to the yum-yang(陰陽) attribute of three-yum and three-yang(三陰三陽), the bolt-leaf-hanges(關闔樞) theory, and the large or small of gi-blood(氣血多少) and researching the Yangshangsun(楊上善)'s theory. The result is summarized like this. First, wherease the order of the change of three-yum and three-yang(三陰三陽) which is explained by Yangshangsun(楊上善) consider the change of yangi(陽氣) in body most important, the order of the change gaeggi(客氣)'s three-yum and three-yang(三陰三陽) considers chungi(天氣) most important, and the order of jugi(主氣)'s three-yum and three-yang(三陰三陽) considers jigi(地氣)'s change of ohaeng(五行) most important. If the order of change three-yum and three-yang(三陰三陽) in the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ is considered, each of taeyang(太陽) and soyum(少陰) are expressed as the base of yum-yang(陰陽) and yangmeong(陽明) and taeyum(太陰) are expressed as the palmy days of yum-yang(陰陽), soyang(少陽) and gyolyum(厥陰) are expressed as pacemaker(樞杻) which controls the change of yum-yang(陰陽). Thus, each has something in common that is fettered by the inside and outside. In the flow of channel(經絡), taeyang(太陽) and soyum(少陰) take charge of the behind of body, yangmeong(陽明) and taeyum(太陰) take charge of the front of body and soyang(少陽) and gyolyum(厥陰) take of the side of body. Second, in Yangshangsun(楊上善)'s bolt-leaf-hanges(關闔樞) theory, three-yum(三陰) is regarded as inside, three-yang(三陽) as outside, so when bolt, leaf and hanges fulfil their duties in inside and outside, the life(life force) is thought to be revealed normally. It is impossible to understand the bolt-leaf-hanges with the conception of the inside and outside which divide three-yum and three-yang(三陰三陽) into taeyang-soyum(太陽-少陰), yangmeong-taeyum(陽明-太陰), soyang-gyolyum(少陽-厥陰) according to yum-yang(陰陽) attribute, hence it need the special conception that is taeyang(太陽)-taeyum(太陰), yangmeong(陽明)-gyolyum(厥陰), soyang(少陽)-soyum(少陰) which center on their duties in inside and outside. In the denunciation of the word open(開) and bolt(關), because Yangshangsun(楊上善) said that the duities of taeyang(太陽) and taeyum(太陰) are shutter(閉禁), bolt(關) is coincided with that significance. Third, with explaining the large or small of gi-blood(氣血多少) of three-yum and three-yang(三陰三陽), Yangshangsun(楊上善) expressed the inside and outside either in the same way or differently. Because the inside and outside is interior of body and exterior of body, it is the explanation that is noticed by the fact that the property of large or small of gi-blood(氣血多少) is either able to be same or different. In this viewpoint, if we unite the contents about large or small of gi-blood(氣血多少) of ${\ll}$Somun(素問)${\gg}$, ${\ll}$Yeongchu(靈樞)${\gg}$, we will find that the descriptions of large or small of gi-blood(氣血多少) of three-yang(三陽) in ${\ll}$Somun(素問)${\gg}$ ${\ll}$Yeongchu(靈樞)${\gg}$ correspond with the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$, but in three-yum(三陰), the contrary presentations exit. The reason is that large or small of gi-blood(氣血多少) of three-yum(三陰) isn't only expressed as che(體) in the point of che-yong(體用), but as a point of yong(用) that is a phenomenon. As researching the original of ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ and Yangshangsun(楊上善)'s notes as a center about three problems that are yum-yang(陰陽) attribute, the bolt-leaf-hanges(關闔樞) and large or small of gi-blood(氣血多少) of three-yum and three-yang(三陰三陽), I, the writer, tried to explain the part which is written differently or has uncertain conception in the book ${\ll}$Somun(素問)${\gg}$ and the book ${\ll}$Yeongchu(靈樞)${\gg}$, but the concrete result of the work like this will be judged according to the question how many theories are correspondent with real presence at a sickbed. Hence, the work to veryfy the theories in the future will be left as assignment.

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통일신라시대 월지(月池) 입·출수 체계의 원형과 구조 (The Prototype and Structure of the Water Supply and Drainage System of the Wolji Pond During the Unified Silla Period)

  • 김형석;심우경
    • 헤리티지:역사와 과학
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    • 제52권4호
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    • pp.124-141
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    • 2019
  • 연구는 월지(안압지)의 수질 관리 문제를 유지용수의 순환 체계와 연관지어 접근하였다. 이를 위해 연못의 순환체계와 관련 깊은 입·출수 체계를 검토하였으며, 기존의 입·출수시설 외에 선행 연구에서 제기되었던 추정 입·출수시설을 분석하였다. 입수시설을 검토한 결과, 현재 입수구인 월지 동남측 호안 입수시설은 남북 담장을 사이에 두고 동편의 정원시설(경석, 곡수로, 저수시설)과 수로로 연결된 것으로 파악되었다. 월지 동편 조사에서 별도의 시설군이 있었던 것으로 보이며 1920년대 실측 도면에 경석군이 확인된 것이 이를 뒷받침한다. 추정 입수구인 남서측 호안 입수시설은 월지 서편 건물지 임해전(臨海殿) 터에 남아 있는 화강암 수로와 연관성이 있어 보인다. 월지 남서측 호안을 향해 경사가 낮아지고, 거름망을 꽂았던 홈, 1920년대 실측 도면과 1975년 측량 도면의 입수구에 경석이 배석되어 있는 것으로 보아 깨끗한 물을 입수시키기 위한 것으로 판단된다. 출수시설과 관련하여 북측 호안 출수시설은 총 5단계로 구성되어 있는데, 이 중 목제 수로와 장대석군 집수시설의 기능은 월지의 물을 배수하기 위한 시설만으로는 보이지 않는다. 목제 수로에 나무 물마개가 있는 점과 마지막 단계에 집수시설이 있는 점으로 미루어보아 상황에 따라 발천의 물이 역으로 입수될 수 있다고 판단된다. 즉 북측 호안 출수시설은 양방향으로 물이 드나들었으며 장대석군 집수시설을 통해 개폐 가능한 목제 수로로 입수되기도 한 것으로 판단된다. 추정 출수구인 서측 호안 출수시설은 북측 호안의 출수시설과 매우 유사함을 볼 때 신라시대에 존재하였거나 후대의 어느 시점에 북측 호안 출수시설을 모방하여 만들었을 것이라는 추정 외에는 어려운 실정이다. 다만 조선시대 어느 시점까지는 농업용수 공급을 위한 출수시설로 기능하였을 것으로 보인다. 이상과 같이 월지는 신라 왕경 중심부인 동궁의 시설과 유기적으로 얽혀 있는 체계화된 배수망에 의해서 입·출수가 이루어졌다. 이를 통해 월지를 비롯한 각 시설군에 물이 입수되었으며 왕경 중심부의 중요한 인공 하천인 발천(撥川)을 통해 남천(南川)으로 연결되는 배수 체계를 가지고 있었다.

부산항 신항 최적의 교통망 수립에 관한 연구 (A Study on the Establishment of Optimal Transportation Networks in Busan New Port)

  • 박호교;최양원
    • 대한토목학회논문집
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    • 제37권1호
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    • pp.125-132
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    • 2017
  • 부산항 신항은 항만의 대형화 및 하역장비의 현대화와 상해, 싱가포르 등 경쟁항만과의 중심항만 선점 필요성 등 세계해운항만 여건 변화에 대응하기 위해 물류중심항만(Hub Port)으로 건설을 목표로 추진되고 있다. 현재 북컨테이너 부두 및 남컨테이너 부두 등 23선석 운영 중에 있으며, 장래 서컨테이너 부두, 남컨테이너 부두 등에 2020년까지 45선석 규모로 확장될 계획이다. 또한 기 준공된 북컨 외에 웅동지구 1,2단계, 서컨 1,2단계, 남컨 항만배후부지 등 항만배후단지 개발이 동시에 추진되고 있다. 따라서 이러한 개발계획을 반영한 장래 교통수요를 예측하여 부산 신항의 교통체계의 문제점을 도출하였다. 부산항 신항의 교통체계 문제점은 부산항 신항 제2배후도로와 연계되는 남북축 도로의 주요교차로의 교통혼잡이 발생하고, 장래 증가될 교통량 대비 신항로(북컨 임항도로)의 용량이 부족할 것으로 예상되었다. 또한 부산항 신항 제1진입도로와 국도2호선이 직접 연결되지 않아 신항북로 등으로 우회교통량이 발생하는 문제점이 있는 것으로 파악되었다. 이에 본 연구에서는 부산항 신항의 원활한 교통처리를 위한 3가지 교통체계 개선방안을 제시하였다. 첫째, 첫째, 부산 신항 제2배후도로와 연계되는 서"컨"남북간 교통축에 대한 주요교차로 운영 및 부교차로의 우회전 진입,진출만 허용하는 방안, 둘째, 존 보도 및 중앙분리대 공간을 활용한 신항로(북"컨"임항도로) 차로 확장방안, 셋째, 부산항 신항 제1진입도로에서 지방도 1042호선 직결 진출입램프 설치하여 국도2호선 방면 연계방안이다. 이러한 개선방안의 효과를 측정하기 위해 Micro Simulation Package인 Vissim을 사용하여 분석하였다.

사질토양에서의 pH조건에 따른 Zn의 이동특성 (Transport of Zn Ion under various pH Conditions in a Sandy Soil)

  • 박민수;김동주
    • 대한환경공학회지
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    • 제22권1호
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    • pp.33-42
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    • 2000
  • 중금속은 토양 내에서 비보존성 화학물질로 작용하므로 흡착에 의해 지연효과가 발생할 수 있고 흡착은 pH에 영향을 받는다고 보고된 바 있다. 그러므로 토양 및 지하수 오염을 예방하고 복구하기 위해서는 다양한 pH조건에서 중금속의 이동형태를 파악하는 것이 중요한 연구과제가 된다. 본 연구에서는 사질토양에서 pH에 따른 중금속의 이동특성을 연구하기 위하여 배치실험과 주상실험올 수행하였다. 배치실험의 경우 초기농도별로 11가지의 $ZnCl_2$ 40 mL 용액과 사질토양 10g을 교반기에서 72시간 반응시켜 평형상태에 도달하게 한 후 용액을 채취하여 Zn, Ca, Mg의 세 가지 양이온을 ICP-AES로 분석하였다. 주상실험은 3가지 pH조건 (7.7, 5.8, 4.1)에서 10 g/L의 KCl과 $ZnCl_2$를 추적자로 사용하여 순간주입 (pulse injection) 형태로 토양시료 상부에 투입한 후 Time Domain Reflectometry (TDR)를 사용하여 10 cm 깊이에서 잔존수농도를, EC-meter와 ICP분석을 통하여 20 cm 깊이의 하부 경계면에서 침출수농도를 분석하였다. 배치실험 결과, Zn은 Ca, Mg와 이온교환의 형태로 흡착이 발생하였고 등온 흡착방정식의 각 모델 (Linear, Freundlich, Langmuir)별로 최저 1.2에서 최고 614.1의 지연계수를 나타냈다. 주상실험에서도 모든 pH조건에서 Zn이온이 이온교환을 하여 흡착이 발생하였으나, 잔존수와 침출수 형태의 파과곡선 모두에서 Zn이용의 첨두농도 도달시간이 K이온과 일치하여 지연효과는 발생하지 않은 것으로 나타났다. 이는 정상류 상태로 부과한 낮은 배경농도의 용탈수내에 Zn보다 강한 이온교환능을 가지는 원소가 존재하지 않아 Zn의 탈착이 발생하지 않았기 때문이다. pH가 낮을수록 Zn는 용액내 수소이온 ($H^+$)의 증가로 치환능이 감소하여 첨두농도가 높게 나타났고, 상대적으로 치환되는 Ca, Mg의 양은 줄어들었다. 따라서 본 연구에 적용된 배치실험과 주상실험의 조건하에서는 Zn이온이 이온교환반응에 의한 흡착이 발생하였으나 지연효과는 발생하지 않았고 가장 낮은 pH에서 첨두농도가 최고 12.7배까지 증가하였다.

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The current state and prospects of travel business development under the COVID-19 pandemic

  • Tkachenko, Tetiana;Pryhara, Olha;Zatsepina, Nataly;Bryk, Stepan;Holubets, Iryna;Havryliuk, Alla
    • International Journal of Computer Science & Network Security
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    • 제21권12spc호
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    • pp.664-674
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    • 2021
  • The relevance of this scientific research is determined by the negative impact of the COVID-19 pandemic on the current trends and dynamics of world tourism development. This article aims to identify patterns of development of the modern tourist market, analysis of problems and prospects of development in the context of the COVID-19 pandemic. Materials and methods. General scientific methods and methods of research are used in the work: analysis, synthesis, comparison, analysis of statistical data. The analysis of the viewpoints of foreign and domestic authors on the research of the international tourist market allowed us to substantiate the actual directions of tourism development due to the influence of negative factors connected with the spread of a new coronavirus infection COVID-19. Economic-statistical, abstract-logical, and economic-mathematical methods of research were used during the process of study and data processing. Results. The analysis of the current state of the tourist market by world regions was carried out. It was found that tourism is one of the most affected sectors from COVID-19, as, by the end of 2020, the total number of tourist arrivals in the world decreased by 74% compared to the same period in 2019. The consequence of this decline was a loss of total global tourism revenues by the end of 2020, which equaled $1.3 trillion. 27% of all destinations are completely closed to international tourism. At the end of 2020, the economy of international tourism has shrunk by about 80%. In 2020 the world traveled 98 million fewer people (-83%) relative to the same period last year. Tourism was hit hardest by the pandemic in the Asia-Pacific region, where travel restrictions are as strict as possible. International arrivals in this region fell by 84% (300 million). The Middle East and Africa recorded declines of 75 and 70 percent. Despite a small and short-lived recovery in the summer of 2020, Europe lost 71% of the tourist flow, with the European continent recording the largest drop in absolute terms compared with 2019, 500 million. In North and South America, foreign arrivals declined. It is revealed that a significant decrease in tourist flows leads to a massive loss of jobs, a sharp decline in foreign exchange earnings and taxes, which limits the ability of states to support the tourism industry. Three possible scenarios of exit of the tourist industry from the crisis, reflecting the most probable changes of monthly tourist flows, are considered. The characteristics of respondents from Ukraine, Germany, and the USA and their attitude to travel depending on gender, age, education level, professional status, and monthly income are presented. About 57% of respondents from Ukraine, Poland, and the United States were planning a tourist trip in 2021. Note that people with higher or secondary education were more willing to plan such a trip. The results of the empirical study confirm that interest in domestic tourism has increased significantly in 2021. The regression model of dependence of the number of domestic tourist trips on the example of Ukraine with time tendency (t) and seasonal variations (Turˆt = 7288,498 - 20,58t - 410,88∑5) it forecast for 2020, which allows stabilizing the process of tourist trips after the pandemic to use this model to forecast for any country. Discussion. We should emphasize the seriousness of the COVID-19 pandemic and the fact that many experts and scientists believe in the long-term recovery of the tourism industry. In our opinion, the governments of the countries need to refocus on domestic tourism and deal with infrastructure development, search for new niches, formats, formation of new package deals in new - domestic - segment (new products' development (tourist routes, exhibitions, sightseeing programs, special rehabilitation programs after COVID) -19 in sanatoriums, etc.); creation of individual offers for different target audiences). Conclusions. Thus, the identified trends are associated with a decrease in the number of tourist flows, the negative impact of the pandemic on employment and income from tourism activities. International tourism needs two to four years before it returns to the level of 2019.