Friday, October 14, 2011

Update Oct.7th - Oct.13th


Time for some thesis progress update.

THESIS ADVISOR

My thesis advisor is going to be Pierre Belanger. I worked with Pierre in Fall 2009 for my first core studio at GSD, which is one of my favorite studios ever. Even better, we got distinction for that project.

After graduated from SCI-ARC with B.Arch degree in Spring 2009, I decided to learn something different. Pierre is the one who show me how DIFFERENT landscape architecture can be from architecture: they have different scale, perspective and approach. For me, the best part in life is about experiencing those thousands of ways to look at something, instead of what you are looking at. 

I was auditing Pierre’s ‘Theories of Landscape as Urbanism, Landscape as Infrastructure: Paradigms, Practices, Prospects’ during my early stage of thesis topic exploration. I found it quite helpful. He always starts by asking questions which are thought provoking. For example, his question during one class ‘What makes Europe so beautiful?’ leads to his argument that ‘they know how to make good use of their underground.’ He mentioned Germany were using a process by which they would take trash and other toxic material and bury it in sites that had already been dug for another purpose, such as granite quarries or coal mines. This in turn allowed them to use the landscape above instead of building landfills like people do here in the States.

One of the case studies he showed us is the Heilbronn Underground Waste Repository (Austria-Germany).

‘Austria’s wasteshed can be divided into three streams: ash, slag and hazardous waste. As the respective residues of incineration and smelting processes, ash and slag are handled within the borders of Austria, while hazardous waste is transported abroad to designated storage facilities across the European Union (EU). According to the German Federal Environment Agency, Germany boasts the highest concentration of landfills and is considered to be the most significant importer of waste of all EU countries. Maintaining the bucolic character of Germany’s rural landscape, most of its facilities are located far below the earth’s surface, in former underground salt mines developed between the 14th and 20th centuries. Currently, Germany maintains approximately 24 mine-filling sites for two types of waste elimination: mine-valorisation sites (tourist sites) and underground landfills (waste storage facilities). Lacking surface and sub-surface storage capacity, Austria is currently employing the former Heilbronn-Kochendorf salt mine in southern Germany as a disposal and containment site. As an endlager, the Heilbronn-Kochendorf underground complex will provide permanent storage for the more than 10,000 tons of hazardous waste generated by the petro-chemical industry. Part of a network of active and decommissioned mines, Heilbronn is an underground complex that, through mining over the past two centuries, has created over 45 million cubic metres of underground cavities, tunnels and shafts. In order to safely store hazardous materials, waste in the Heilbronn-Kochendorf underground complex is geologically isolated from the groundwater and biosphere by the existing strata of salt and clay layers, according to practices sponsored by the European Atomic Energy Community since 1955, creating stable conditions for permanent disposal. With the more than 1 billion cubic metre storage capacity below Germany, there is reportedly enough capacity to supply of hazardous waste storage services for big cities across the European Union during the next 150 years. (Sources: Südwestdeutsche Salzwerke AG, 2008, City of Vienna, Endlagerung in Deutschland, 2007 / information collected by Maria Julia Budnik and Ingebjorg Lose)






All images above are collected and produced by Maria Julia Budnik and Ingebjorg Lose

To me, the most beautiful part of landscape is always something ‘invisible’. The landscape researches are quite often about mapping those ‘invisible’ facts, systems and flows (like what we did for Nutrient Cycling project), which is an extremely exciting process.

Relate this back to my thesis. During our first thesis prep class, we were asked to talk about what our thesis going to be about. At that moment, the phase ‘the art of touching the ground lightly’ haven’t came to my mind yet and I have no idea where Laos is and the have never hear of 'UXO' in my life. However, I do know what I am interested in. I am always fascinated by how violently people ‘touch the ground’ throughout history and its subsequent spatial quality and territory characteristic: coal mining, land reclamation, landfill, etc. Huge amount of materials being moved, huge energy flow and tremendous change created to the system amazed me all the time. I was saying in that first class that I am going to do something with the land reclamation in Netherlands. Then after Pierre’s theory class and looking at the Heilbronn Underground Waste Repository, I picked my site in Shanxi province, China, trying to do a project by creating a connection between the problem of abandoned coalmine to the problem of lacking of space for landfill in the same region. Then two days later, after realizing how hard it is to get some China mainland data, I finally picked another topic and change my site-postwar landscape in XiengKhuang, Laos. It seems like my potential thesis site and topic has been jumping around the world in a short 3 days, however, they all share the same characteristic, which is 'how we touch the ground'. 


The thesis is about an argument. The design project is just an example helps to explain the argument. That’s my way of taking the thesis and I keep this value on things in mind all the time. For example, while I am doing thesis research on Laos, there are huge amount of data and fact I dig out everyday. It is really easy to get frustrated during this process: you have to compare information on the same topic but come from different sources; there is always data you know does exist, but can never get it due to reasons ranging from political, historical or authorization issue. However, when I realize the data just need to show the fact that ‘we touch the ground violently’, that’s enough. What matters the most is the argument ‘we need to learn how to touch the ground lightly’; and what matters the most is I am going to do a design project (no matter in Netherland, China or Laos; no matter about reclamation, coal-mining or UXO leftover) and showing you what beauty or benefit can be generated by utilizing ‘the art of touching the ground lightly.’

About how to work with Pierre... He is the one whose thoughts are always so smart and fast, plus the fact that he has super strong mind; I am not as smart as he does, but my mind is even stronger and I am always quite clear about what I want the most - in terms of doing a thesis project, that’s something positive. I will learn as much as I can from Pierre, and at the same time, I am going to do something driven by my own heart not others. What I am expecting from my thesis is not how good a project is in the end, rather, I am using thesis as a media to communicate with other people, sharing my truest thinking and feeling about something in this world.


SITE DESCRIPTION

I got the two pieces of the most important data less than 24h before my thesis prep pin up today. I have been sending more than 20 emails, more than 10 facebook messages, making calls to 5 organizations overseas who supposed to have those data. On the 11th, I found an image showing the information I really need on this website and then send the blogger an email:

Peter, who is the blogger writing this article, send me over the data which I have been looking for more than one month. Peter is a PhD candidate in the Department of Epidemiology within the School of Public Health at the University of Michigan. He kindly share with me the bombing data and we talked about the potential of working together on certain parts of my thesis topic. It is always good to hear the voice of people from other disciplines. It is not just about the diversity of ideas, rather, what interest me the most is the diverse logics on the same topic from different people. As I said in my thesis update few days ago, the thesis process is so interesting. You started to know something you have never heard of, and you began to know people that you may never talk with or meet in your whole life.

Here is my site description board.

I started converting the excel data got from Peter to something can be visualized in GIS around 11am yesterday. Then after studio meeting around 8pm, I started to work on putting together different layers of information together and some quick graphic test, finally went back home at 2am and did my presentation of the board at 8am


The site description board definitely need more work and it is good learn some really good stuff from Gareth, John and Silvia Benedito. John suggested we memorize our 250 words abstract (which I have to keep editing and updating through the whole semester), start our presentation with who I am and what my thesis is about, where is my site, and we have do this in a fast way to let people who have never seen our project or know nothing about our topic and site start understanding what you are doing quickly. As Paola said, the way you present your thesis, the thesis representation method should all related to the thesis topic. I remember when Andrew talked about his project ‘staging ground’, he said he was not satisfied with how he ended up his thesis presentation- ‘I end my presentation on one of this rendering, which didn't wrap up everything’.

Then Silvia suggested us to write down 5 questions and ask ourselves, which I found really useful. I wrote review of Paola’s thesis from last year. At the beginning of her thesis preparation, it was just about how to deal with a landscape in which everything already happened in terms of planning, development and building; then a set of five questions, which she brought up at the beginning of her thesis presentation, define more precisely what she was trying to say: 
When the function is obsolete, what does it becomes to be?
When space is forbidden, what does it becomes to be?
When a designed artifact interacts with the system, what does it becomes to be?
When a map line touches the land, what does it becomes to be?
When an anthropogenic landscape is seen by an other point of view, what does it becomes to be?

Finally, with the process of her thesis presentation goes, seems all these complexity was simplified into one simple question: how to cross the boundaries?


One more thing about my site description board is that, after my presentation, I realize I only talked about half of the characteristic of the beauty of my site. The site 'BEARING THE TENSION BETWEEN LIFE AND DEATH': 'While the UXO buried ground creates a life-threatening picture; in certain areas, the scars on surface are transforming from a symbol of death into one of life: bomb-craters have been made to yield an alternative harvest, in an ingenious replacement of the rice fields they otherwise disrupt. For example, some craters are made into fishponds, which become good sources of protein. ' My site description should be represented in a way showing 'the tension between life and death': with this board showing the 'death' and another one showing the beauty of those craters, the merging self-healing process of the war-disturbed landscape. 


It is quite easy to be attracted by all sorts of data I found during the research process, have to keep in mind which piece I have to show and which piece shouldn’t to help amplifying my topic and argument - ways we touch the ground.

Courtesy of Bomb Harvest

High-altitude photographic mosaics, photo by H. Westing and E. W. Pfeiffer

photo by H. Westing and E. W. Pfeiffer





One thing I am struggling about recently is to find good pieces of readings than can help frame or inform my argument. As Paola told me, her disciplinary position was informed by some readings she did in recent years in philosophy and anthropology fields. One of the book inspired her most is : "We Have Never Been Modern", by Bruno Latour, French sociologist and anthropologist. Bruno framed the definition of 'hybrid' that Paola has used as reference in the thesis.  In his opinion, hybrid is the system, which constitutes the real world. He relates the failure of modernism with the modernist dichotomy between the system and the abstract models humans used to understand, and represent it. I can tell from Paola’s thesis how important this piece of reading help to frame her argument and her final design. I need some key words or key sentences help me to purify my argument and reminds me what I want to do the most all the time.


One more thing worth mention is our thesis prep trip to Sackler Museum today. When you look at a painting you are asked to focus; you are trying to discover the decisions made by the artist. It is at that moment, you feel you are talking with the artist and certain connections are created between you two. 


The best part of this museum trip is, I see ‘things make connections in different ways’.

Friday, October 7, 2011

OLD WORKS_PART1


Uploading some of my old works.

GSD, MLA Core studio, 2009 FALL
Team: Xiaoxuan Lu, Amy Linne, Forbes Lipschitz
Instructor: Pierre Belanger

Studio开始于2个深入的mapping练习。
第一个research是关于project的场地:South Weymouth Naval Base的情况分析。这次的studio research是我上学以来第一次觉得research是有价值的,concept是可以基于research中得来的重要信息,无论是场地的历史变迁,场地的水文,植被,还是交通网等等,似乎都可以成为设计概念的起点。
第二个research是关于landscape as infrastructure的研究。每一个组由2个人共同研究一个project. 我所做的是 San Francisco  Jepson Prairie OrganicsJepson是一个生产compost的公司。Compost的意思是堆肥,听起来傻乎乎的,其实是一个满有趣的过程。学了设计5年,从来没有关心过infrastructure,对于compost可以说在做research之前一无所知。对于landscape as infrastructure这个statement, 通过这个学期的studio我终于充分了解。关于compostresearch, 学到的如果只是如何堆肥,堆肥的过程是怎样的那就很没有意义。以前做的很多应付作业的research大多都仅仅停留在这种表象上。但是这次却有很大不同。Research focuscompost作为infrastructure,它所需要的系统上。研究首先绘制了San Fransisco地区的food waste的来源,quantity, frequency的地图。通过mapping,让我第一次认识到,一个小小的场地,是属于一个regioncomponent, 这就是infrastructure的有趣之处。它的存在是基于一个system的建立。Compost解决了 San Francisco food waste, 同时创造了优良的肥料运用于整个地区的土壤改良,形成了良好的循环。其他同学也做了各种有趣的mapping,他们的题目也是各种各样。

1.      Regional Flows


2.    Jepson Prairie Organics On site Operation


3.    In-Vessel Compositing


4.    Jepson Prairie Organics Composting Facility


Studio的老师Pierre Belanger 同时也是我们另外一门课,Landscape Planning for the 21st Century的老师。课的内容也是有关infrastructure的,非常有意思,每次都有不同的专家演讲。其中令我印象最深刻的是关于freeway的演讲,里面谈到了infrastructure, freeway, 之所以有很多的问题,比如freeway对区域的切分与隔断,源于infrastructuredesign methodology. 其中提到有趣的一点是,美国最初的道路建设是属于美国军事国防系统的,freeway的目的仅仅是快速,安全。Design的概念其实并不存在,freeway之于区域的contribution到底是什么从来没有人考虑过。总之,无论是我的research还是讲座都让我第一次思考了什么是infrastructure以及landscape as infrastructure这个概念。

回到studio project上来。Studio brief要求的我们做的就是envision the future of the South Weymouth Naval Base as a public regional infrastructure’,建造一个‘reformulate process-based, implementable landscape infrastructures that responds to the pressing needs of the region and the future urban imperatives of the Greater Boston Area towards the year 2050.’ 对于studio所设立的目标,我也和很多人讨论过它的意义以及loop hole. 比如我们能否真的设计建造一个system, 从而有益于一个regionscale?就像WYHcritic的,完美的系统是不存在的,是否当你精心建造一个系统的时候反而在embed一个潜在的危险——当系统崩溃的时候所造成的影响更大范围更广?但是我认为,这个project的意义并不在于我是否学会建造一个区域系统以及我是否相信区域系统存在的必要性,对我来说,studio这次最大的收获是在于用一个不同的眼光看待问题。对design本身到底是什么,以及作为一个designer需要掌握的知识、能力,以及zoom out to region scale去理解同一个问题可以得到完全不同的景象,这些都让我收获颇多。

STUDIO BRIEF:
Landscape Infrastructure Strategies
After the two primary researches, the objective of the third phase in studio is to envision the future of the South Weymouth Naval Base as a public regional infrastructure.
Stemming from the existing ecology of biophysical resources, the objective of this phase of design is threefold:
To capitalize on the current stalemate of the development proposed for the site by south shore Tri-Town Development Corporation, to fully exploit the current de-urbanization (negative population growth) of Abington-Rockland-Weymouth region, and reformulate process-based, implementable landscape infrastructures that responds to the pressing needs of the region and the future urban imperatives of the Greater Boston Area towards the year 2050.

 Project 最后做的是 Nutrient Cycling。这和我research做的是compost有一定关系。想法的出发点是security’. 原先用于领空防御而存在空军基地,当它被废弃掉了原先的功能,是否能够在一个新的角度作为一个为了secure’ something而存在的infrastructure. 所以,目标就锁定在food security这个概念上。第一步就是去找已有系统的loop hole。方法是用GIS进行map, 研究了2个题目:第一个是National Harvested Acreage’ map的分析结果是:美国的主要农业作物包括小麦,玉米,小型蔬果生产。东北部(p.s.场地所在的 New England 位于东北部 ),主要是大湖地区,生产大量的玉米以及一部分蔬果,小麦生产非常稀缺。而中部地区有着大量的小麦种植,这要源于地区肥沃的表层土。随着急速上升的汽油价格以及越来越明显的气候变化,美国东北部试图提升它的地区性食品供应的安全性以及自我供应的可能性。所以我们的project的切入点就是:应用地区的organic wastes (在美国,如分类垃圾中的食物类,一半学校、餐馆等等是重要的来源)作为营养物质的来源,改良该地区的土壤,从而为地区的种植多样性提供可能,以此来提高regional food security’这个问题。

PROJECT PROPOSAL:


Nutrient Cycling
1.
Urban - Agricultural Patterns
The relationship between urban hubs and the agricultural lands that support them has largely been one of linear consumption, consumption of both commodities and land for development. This oblique aerial of a suburban New England neighborhood highlights in red agricultural land lost to development in the past 10 years. The farmland that does remain on the urban periphery is often overworked, becoming nutrient deficient and dependent on synthetic fertilizers. With the majority of food waste going into landfills, the relationship of the city and agricultural land continues to be uni-directional.
1:城市农业模式
城市聚集区以及供应其生存需求的农业用地之间的关系一直是一种单向线性消耗:城市的发展消耗了大量农业用地。这张新英格兰地区郊区的俯视图,用红色标出了在过去10年间农业土地的流失。而那些仍然存在于城市边缘的农业地,被过渡耕种,营养极度缺失,完全靠依赖人造肥料维持。与此同时,大量的food waste终结在landfills, 这种状况表明,城市(city)以及农业用地(argricultural land)一直都处在单项性的关系中。(农业供应城市,而城市没有贡献于农业生产: the relationship of the city and agricultural land continues to be uni-directional.)


2.
Regional Nutrient Field
By mapping the food waste in the area along with landfills, existing compost facilities, and productive cropland, a form of nutrient inefficiency is revealed. The greater Boston area produces 270,000 metric tonnes of food waste per year, 97 percent of which goes to landfills and incinerators. Only five composting facilities are in the immediate area, most of which are only permitted to handle 3,000 tonnes per year, while the largest can only handle 23,000 tonnes per year. None of the existing facilities are coordinated with municipal waste management or have the capacity to produce certified organic compost.
2:城市化的区域性营养地貌Urban Regional Nutrient Field)
我们可以从这张看到 Eastern Massachussets地区的大背景。通过mapping区域性食品残余(food waste) (橙色点),垃圾填埋 landills) (深红色点),现有的 existing compost facilities (把有机物的残骸转化成混合肥料的机构) (圈出的),以及农业生产用地(灰色的),我们揭示了区域性的营养物流动的极度效率缺失(nutrient inefficiency ) The greater Boston area (场地紧邻的地区),产出270,000吨食品残余,97%的食品残余结束在垃圾填埋以及废物的焚化炉。The greater Boston area地区附近只有5composting facilities, 其中大部分每年只能处理3000顿食物残渣(最大的一个每年也只能处理23000顿)。与此同时,5composting facilities没有一个是和区域性垃圾管理相协作,也没有一个有资格生产有机的混合肥料。

3.
Nutrient Inefficiency in North America
Zoom out to an even larger scale, the widespread land-filling of organic waste and simultaneous artificial fertilizer consumption reveals critical nutrient inefficiencies in North America and abroad.
3:北美营养的效率缺失
zoom out to a even larger scale, 这一张map对比了2个事实:一是,广泛分布的对有机物残骸的垃圾填埋 The widespread land-filling of organic waste),二是,与此同时人造化肥的极度消耗。两者之间没有建立起应有的联系,这导致了北美以及在global scale上严重的营养的效率缺失。(map中包含了美国肥料进出口的数字以及全球的肥料消耗)


4.
Nutrient Inefficiency in North America-Beef Production and Processing
In the era of global warming and rising oil prices, the systems of meat production and processing is increasingly fragile and unsustainable.
These two seemingly unrealated problems acturally create an opportunity for us to think about nutrient cycling in a new way by creating a relationship between the two.
The location of our site makes it a perfect spot for creating a new infrastructure benifiting the region.
4map揭示了这样一个事实:通过map牛肉的生产以及加工,说明在全球气候变暖以及汽油价格彪升的情况下,现有的肉类生产及加工过程变得越来越脆弱,并且 unsustainable.
这两张地图看起来在揭示2个不相关的急迫的情况,实际上给了我们一个机会去重新认识与思考营养循环。我们通过在2者之间建立联系,来解决2者同时面临的岌岌可危的状况。我们的场地,紧邻大波士顿地区,拥有良好的食品残渣来源,因此我们认为它可以成为一个运用compost过程以及肉类生产来帮助地区发展的基础设施。(It is a perfect spot for creating a new infrastructure benifiting the region)



5.
Spatial Requirements
In addition to location, the existing conditions of grassland and paved surfaces make the site well suited for livestock and composting operations. We then looked at the spatial and physical requirements of these operations. The necessary components for composting include paved surface, a berm, swale and shelterbelt to control runoff and mitigate wind. Livestock were selected based on contamination levels, existing conditions and market demand. For each of the livestock we determined the land requirements for pasture and hay production and additional requirements including shade, water and shelter. In section it becomes apparent how these systems would interact.
5:基础设施空间需求 Spatial requirements)
这张图是一些基本的数据和图表,说明区域性有机肥料生产的空间要求,牲畜饲养及肉类加工的空间需求,重要的野生动物生存区的保护等等信息。例如,能够处理波士顿地区1.75 million人口产生的食物残渣的compost facility需要13 hectares混凝土地面进行分类、处理等工作。(场地上原有的飞机跑道大约13.5 hectares ,所以这个场地不需要额外的地面建设去满足infrastructure的需求,从经济上讲,这也为project的可行性提供了支持)堆肥需要考虑包括如下方面:berm,防护林,用于收集和净化compost runoff的低地(swale)。牲畜饲养也有很多要考虑的方面。牲畜的选择及安排基于场地污染物的种类及分布,现有marsh land的分布,以及市场需求。根据不同的牲畜种类,还设定了牧草区,干草区的分区、轮种。总之设计中考虑了各种生态环境因素及实际的操作(毕竟是landscape architecture)


6.
A series of on and off-site analyses inform the design of site.
6
6.场地周边及场地本身的分析
场地周边分析包括日照,水文等等,用以确定基本的功能分布。
场地本身的分析主要在讲我们如何建造,建造的顺序及材料安排如对现有场地上材料的应用等等。另外,一部分肥料用于治理场地上的现有污染。就是用capping来代替一般常用的soil removel, 以减少花费。


7.
Operative and Strategic Phasing
As composting operations are initiated and on-site contamination remediated, livestock production, processing, and distribution are integrating, forming Field Grade, Inc.
7:场地演变
详细第说明了 composting operations作为起步,带动的场地污染物清理,牲畜饲养、处理、肉类消费等等,以及我们虚拟的Field Grade, Inc.’的成立。


8.
Rotation Strategy
This plan shows a projection of the site in 2020. The livestock operation consists of 188 hectares, the composting 13 hectares with 2.5 hectares for a regional market. The buildings, used for slaughtering, shearing, milking, and pasteurization operations, and access roads are sited to allow for daily operations, public events, and livestock delivery. The fields are divided into two zones, one for grazing pasture, one for hay, and these are rotated annually. Within the pastures, the animals are rotated four times per month to prevent overgrazing of pasture grasses and to maintain healthy, productive land.
8. Rotation Strategy
在讲场地上营养物质的循环。主要就是应用牧草轮种等等方式保持土壤的营养及改良过程。


9.
Operational Sections
In section it becomes apparent how the plan responds to subsurface conditions and how the topography registers these conditions.
A compost mixture is used to cap contamination, creating a rise in the land where this is taking place. In other parts of the site, compost has been used to cover the runway or fill in areas where the runway was removed. The covered runway is indicated on the surface by a gap in the hedge row, as the paved surface just under the soil prevents the growth of trees. The ground plane lowers at the bloody wetland to facilitate the cleansing of slaughterhouse effluent.
9:剖面
说明了各个系统之间的场地关系





10.
Views of site reveal the public interface of Field Grade Inc, with particular hubs of public activity along the composting berm and adjacent to the abattoir’s blood-filtering wetland.
10:场景


11.
Emergent Economies
This diagram visualizes the annual cycles of operations which include composting, beef production and processing, dairy, and wool. . There is continuous activity and revenue streams throughout the year with a spike in late summer when livestock processing and the regional market peak due to harvesting schedules. We estimated the operations will generate annual revenue of between $6 and 8 million in direct sales.
11:经济效益的浮现
场地运作提供了持续性的经济活动,其中夏季及早秋最为活跃,当区域市场,牧草生产及畜牧生产都处在运作高峰期的时候。


12.
Site Nutrient Cycling
Nutrient cycling takes place on a regional level and on the site scale as part of daily operations. Our site works as a visualization of nutrient cycling.The organic material collected from the metro-area is taken through a 90-day multi-step process until it becomes nutrient-rich compost which contributes to the vitality of the soil onsite and in the region. Additionally, the livestock play an important role in nutrient cycling through the manure they deposit in the soil and meat and milk products distributed to the region.


13.
Regional Nutrient Network
The site provides the opportunity to view the region through the lens of nutrient cycling. Livestock is brought in from regional farms, processed into meat distributed to local consumers, who subsequently produce their own food waste, which is collected and transported to the site. Compost is distributed to regional farms, who distribute their food to local consumers, and the cycle continues. We start the project by revealing the unbalanced, linear relationship between the urban area and the agricultural land that supports it. However, the site can become a prototype for fostering reciprocity between urban and agricultural lands - creating a synergistic system of nutrient cycling, strengthening and regionalizing the food chain in the process.
13:区域的营养循环
project起于mapping,也在结束的时候用mapping的方法试图展望infrastructure为区域带来的贡献:场地每年能够处理来自30个不同行政区的135000顿食物残渣,将其转变为80000顿的有机肥料,将其再用于区域土壤改良。同时,900顿有机饲养牲畜,将提供300顿的肉类供应该地区,满足地区20%的有机肉类供应。结论就是,一个完整的循环通过这个infrastructure被建立起来达到区域营养物质的有效利用循环。
最后两地上及区域尺度的养循示意