[Sea-sa] [EXTERNAL] SC14 meeting
Shames, Peter M (US 312B)
peter.m.shames at jpl.nasa.gov
Thu Apr 8 21:00:23 UTC 2021
Ok. Sounds like you got your priorities straight.
I agree, by the way, that one “component” may be part of more than one “subsystem”. In fact, if we define “system” as we do in RASDS, as being (potentially) a combo of HW, SW, people, and procedures, it becomes fairly clear that systems cross cut multiple viewpoints. Or, to put it another way, multiple viewpoints can all contribute to an understanding of the architecture of any given “system”.
When is that SC14 Architecture group meeting? I’d like to be present.
Thanks, Peter
From: Fred Slane <frederick.slane at gmail.com>
Date: Thursday, April 8, 2021 at 1:22 PM
To: Peter Shames <peter.m.shames at jpl.nasa.gov>
Cc: Ramon Krosley <r.krosley at andropogon.org>, SEA-SA <sea-sa at mailman.ccsds.org>
Subject: Re: [EXTERNAL] SC14 meeting
Peter and Ray,
I have internationally stayed in the background on this discussion. So, I went to a brewery and helped with a couple of batches. "Hands-on" science, if you will, and much less hypothetical.
I see some benefits in both arguments and sort of understand Ray's suggestion as a calculus for energetic connectivity using integration by parts for the various energies (power, signal, thermal...) while Peter is much more explicit in the physical structures. Ray leaves viewpoints implied until we understand better what we are really talking about. I can even convince myself that a spacecraft is a collection of parts, operating together and can be described as such with no intermediate "levels" Peter is explicitly calling out viewpoints up front. One observation to contribute is that subsystems are functional, not strictly physical or systemic, as some assemblies or parts may support more than one subsystem.
My feeling is that this should be presented to the SC14 Architecture group for discussion.
Peter, I think the mathematical definition of recursion is better as we address Enterprise measures, decomposed and distributed to parts. Maybe not necessary for measures under other viewpoints.
Cheers,
Fred
Frederick A. Slane
Executive Director
Space Infrastructure Foundation
731 North Tejon Street
Colorado Springs, CO 80904
freds at spacestandards.org<mailto:freds at spacestandards.org>
www.spacestandards.org<https://urldefense.us/v3/__http:/www.spacestandards.org__;!!PvBDto6Hs4WbVuu7!Y-ugZBvLzc_kE7Kq9Ys98siqF-f4IK7jYezdTls-39K5nXZztUFKZ8j_OBiQjEV-vURq9IKC$>
+1-719-229-4252
"If you can't describe what you are doing as a process, you don't know what you're doing." ~W. Edwards Deming
On Thu, Apr 8, 2021 at 11:40 AM Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>> wrote:
Hi Ramon,
Sounds like we are in the same ballpark. That’s great. I do think that in any of these viewpoints that there may be a series of views at successive levels of decomposition:
1. Systems of systems
2. Systems
3. Subsystems
4. Etc
I also think, as we discussed, that there may be named “levels” that different organizations wish to impose, and that we can acknowledge without requiring them. And, as we have discussed, there may be processes that for formulated, I think, as part of the Enterprise viewpoint, which I did not list below. This also “owns” organization and requirements objects. I would treat these Enterprise processes and being fundamentally different for Operations processes, even though both are “process” in nature. One is how an organization carries out its business, the other is the details of the operations of the business.
I’m not entirely clear about what you mean by “the operations viewpoint will also describe the physical activities of a mission that is the object of the controls”. Do these “physical activities” include orbits, trajectories, instrument observations, and data downlinks, all of which can be described in the context of the physical viewpoints, and many of which use protocol exchanges, or does it refer to the operational activities that plan obits and trajectories and that carry our sequences of instrument observations and plan data downlinks?
We are getting closer. Let’s see what Fred and the rest of the crew think on Monday.
Cheers, Peter
From: Ramon Krosley <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>
Date: Thursday, April 8, 2021 at 9:48 AM
To: Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Cc: Fred Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>, SEA-SA <sea-sa at mailman.ccsds.org<mailto:sea-sa at mailman.ccsds.org>>
Subject: RE: [EXTERNAL] SC14 meeting
Hi Peter and Fred,
Peter, your summary is in the same ballpark as my thoughts. There are some minor differences, outlined below, which could be decided in Monday’s teleconference.
* Items 2 through 7 all have “physical” in their names, and all are called “viewpoints” in your list. Their stakeholders for design are (in general) different individual subject matter experts, which is consistent with separate viewpoints. The user stakeholders (in general) have interests in more than one of items 2 through 7, which is consistent with a single physical viewpoint with multiple separate subject-matter views. The difference between these two organizations is small and could be resolved either way. Fred, do you have a preference from SC14?
* Your question whether it makes sense to identify physical services is where I found difficulty with the alternative factoring of physical views that I proposed. On many vehicles, the physical services are real, but the need to describe them in the terms of the Services viewpoint is awkward because the physical views already provide the parameters for energy flows without the special syntax of a software service interface. I’m happy with our current Services viewpoint.
* Your correspondence between functional viewpoint and the operations and services viewpoints is a good idea, which allows for various mixtures of human and software implementations of control. Of course, the operations viewpoint will also describe the physical activities of a mission that is the object of the controls.
* The distinction between data connectivity among the nodes of a mission and data connectivity within a single node could be handled by a shallow hierarchy of views within the Connectivity viewpoint.
Ramon
From: Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Sent: Wednesday, April 7, 2021 11:58 AM
To: r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>
Cc: 'Frederick Slane' <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>; 'SEA-SA' <sea-sa at mailman.ccsds.org<mailto:sea-sa at mailman.ccsds.org>>
Subject: Re: [EXTERNAL] SC14 meeting
Hi Ramon,
Thanks for your thoughtful approach to this conundrum. I think it is useful to try on different concepts for the different viewpoints, as a way to sort through the benefits (and deficits) of the different possible configurations.
Much of what you say about the relationships among functions, components, services, interfaces, composition, and the relationships among them ring true for me, but I am not yet sure that we are really on the same page. I think you may be agreeing with something like the following:
1. A functional viewpoint with abstract functions and abstract exchanges of information over logical links.
2. A physical viewpoint with concrete components and concrete connections.
3. A physical/connectivity viewpoint that references the components (by correspondence) but focuses on data system connections and data flows.
4. A physical/structural viewpoint that references the components (by correspondence) but focuses on mechanical connections and energy flows.
5. A physical/electrical viewpoint that references the components (by correspondence) but focuses on electrical connections and energy flows.
6. A physical/thermal viewpoint that references the components (by correspondence) but focuses on thermal connections and energy flows.
7. A physical/propulsion viewpoint that references the components (by correspondence) but focuses on mechanical connections and propulsive energy flows.
8. All of these items 2-7 include interfaces, but they are of different types, #3 is protocols stacks (separate viewpoint), #4 is structural (bolts, welds, etc), #5 is cables and connectors and electrical signals, etc. SEDS is relevant, I believe, for describing #3 and #5. RFM is relevant for describing #1.
9. An information viewpoint that defines information structures, syntax and semantics, and is referenced by correspondence wherever this level of detail is needed. For example, the SEDS data structures would be described in this VP.
10. A services viewpoint which is the documentation of the exposed formal interfaces of #3. I do not know that we would talk of “services” in the context of the other physical viewpoints, but maybe you have other ideas. Does it make sense to take about a “thermal service” or a “propulsion service”?
11. A protocol viewpoint with the usual protocol descriptions and stacks. Referenced by the service interface as an interface protocol binding signature and otherwise for the physical/connectivity viewpoint when those details are needed.
12. An operations viewpoint with activities and actions and process flows that is, in essence, the concrete human implementation of functional flows.
Or maybe this is way off base from what you are thinking. Please let me know. And maybe we need a working WebEx session to discuss this stuff instead of trying to do it in email?
Thanks, Peter
From: Ramon Krosley <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>
Date: Wednesday, April 7, 2021 at 4:00 AM
To: Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Cc: Fred Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>, SEA-SA <sea-sa at mailman.ccsds.org<mailto:sea-sa at mailman.ccsds.org>>
Subject: RE: [EXTERNAL] SC14 meeting
Hi Peter and Fred,
In the second half of my previous email (below) I suggested an alternative way to factor the physical views, which involved changes to functional and services views. I have since experimented with the idea and found it wanting. I’m happy with the physical/connectivity viewpoint as we have been developing it.
Ramon
From: r.krosley at andropogon.org<mailto:r.krosley at andropogon.org> <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>
Sent: Monday, April 5, 2021 4:43 PM
To: 'Shames, Peter M (US 312B)' <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Cc: 'Frederick Slane' <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>; 'SEA-SA' <sea-sa at mailman.ccsds.org<mailto:sea-sa at mailman.ccsds.org>>
Subject: RE: [EXTERNAL] SC14 meeting
Here is how these issues have developed for SOIS:
There are elements of composition, which are the instruments and software objects on board a spacecraft, described by SEDS. Also, there are deployment descriptions, which describe how the elements of composition are put together using subnetworks. The SEDS-described elements have provided and required interfaces, and a deployment description matches the required interfaces with specific provided interfaces to compose a whole vehicle. Recent work in SAVOIR and ancient work in SPA have extended the interface compositionality beyond subnetworks to include physical connections in the deployment description. This compositionality is not yet well expressed in SOIS, but it’s how I understand it.
Here is how that can extend to RASDS:
I think that these two kinds of description, {elements of composition, composition of those elements into an assembly}, cover the gap that you see in limiting ourselves to just interfaces. Fred’s comment that “we only want to standardize the interfaces” is addressed by the fact that we are actually standardizing the languages for these two kinds of description (SEDS in SOIS and RASDS in SAWG). Neither SEDS nor RASDS is standardizing any interfaces, but we have languages now for people to describe assemblies glued by interfaces. Calling the Physical/Connectivity viewpoint the “Physical Interfaces” viewpoint emphasizes what SEDS is doing. For RASDS, we could possibly call it the “Physical Deployment” viewpoint. However, I think that “Physical/Connectivity” says the same thing for RASDS.
This discussion leads to another thought:
Here is how we are currently considering distributing the physical structure and energy transfer information into RASDS:
The Services viewpoint in RASDS describes provided data interfaces. The Functional viewpoint of RASDS indicates abstract deployment links between implicit required and provided data interfaces. The Connectivity viewpoint in RASDS describes concrete deployment links that are conduits for the abstract links in the Functional viewpoint. In the new Physical/Connectivity viewpoint being considered for RASDS, we are proposing to generalize the description of data interfaces and links to describe physical structure and energy transfer in addition to data. Our current direction places all the physical interfaces and links into one viewpoint and uses the Connectivity viewpoint as the mechanism to relate those physical considerations to the data considerations in the other RASDS views.
Here is an alternative way to distribute the physical structure and energy transfer information into RASDS:
This relationship could be organized differently if we are willing to discard the data-centric nature of the Functional and Services viewpoints: In this alternative organization, the Services viewpoint would include physical interfaces for structure and energy transfer, and the Functional viewpoint would include physical functions and their abstract deployment links. The Connectivity viewpoint would include concrete links for physical structure and energy transfer. The Physical/Connectivity viewpoint would not be necessary.
I could work with either of these organizing principles.
Ramon
From: Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Sent: Monday, April 5, 2021 1:53 PM
To: r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>
Cc: Frederick Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>; SEA-SA <sea-sa at mailman.ccsds.org<mailto:sea-sa at mailman.ccsds.org>>
Subject: Re: [EXTERNAL] SC14 meeting
I think physical interfaces may be too limited for all of the physical structural aspect s that may be accommodated by this viewpoint.
I don’t think that “interfaces” expresses structural connection and position particularly well. Nor power & propulsion for that matter. How do you propose to handle those kinds of views in a “physical interface” view?
That said, you could create other focused viewpoints for other aspects of these same “structural” elements.
We need to think this out carefully, along with the existing RASDS Conndctivty viewpoint. It mat be that we shift to some sort of Physical Viewpoint, that is the “home viewpoint” for all of these, including Connectivity, and these other viewpoints reference that physical base through correspondence.
Cheers, Peter
Sent from Peter's JPL iPhone X
Everything should be made as simple as possible,
but not simpler.
~Albert Einstein
On Apr 3, 2021, at 5:01 PM, r.krosley at andropogon.org<mailto:r.krosley at andropogon.org> wrote:
Those are good points, Fred,
The “scales”, “levels”, or “tiers” that you mention are examples that provide alternative names for the boundaries between different scales of descriptions. We should use the word that resonates with folks.
The “Physical Interfaces” is a good descriptive name for the viewpoint to me.
Ramon
From: Frederick Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>
Sent: Saturday, April 3, 2021 11:23 AM
To: Ray Krosley <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>
Cc: Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>; SEA-SA <sea-sa at mailman.ccsds.org<mailto:sea-sa at mailman.ccsds.org>>
Subject: Re: [EXTERNAL] SC14 meeting
Ray,
Recursion is a nice elegant approach. I would hve called it "scalable" instead of "recursive", but that's perhaps a nit.
Recursion may also be another way of expressing the "Levels" as described in NASA HDBK 1005, where we list systems and subsystems and assemblies and so forth.
In feedback from the US SC14 TAG, Alan Kirchbaum suggests "Physical Interfaces", which may be better than "Physical" for that Viewpoint. Thus, Recursion and Physical Interfaces will go a long way in consistently addressing system, subsystem, assembly etc. standards work. We do not really want to standardize anything but the interfaces.
Cheers,
Fred
Frederick A. Slane
Executive Director
Space Infrastructure Foundation
731 North Tejon Street
Colorado Springs, CO 80904
freds at spacestandards.org<mailto:freds at spacestandards.org>
www.spacestandards.org<https://urldefense.us/v3/__http:/www.spacestandards.org__;!!PvBDto6Hs4WbVuu7!dQGp2ush1q1eMLe2LHV-etOfFmzfQdFMbMbIdAyTsh-Ib1elSsQgYVFPuY002rvbe0E12Ce6$>
+1-719-229-4252
"If you can't describe what you are doing as a process, you don't know what you're doing." ~W. Edwards Deming
On Fri, Apr 2, 2021 at 8:29 AM <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>> wrote:
Hi Peter,
One feature that I started to add, but then removed pending discussion, was a recursive structure of the view products. This structure might help to manage the correspondences that are possible. The main example of the recursive structure is two communications/connectivity views: One view that is used in CCSDS has the scope of the mission and has spacecraft, relay vehicles, habitats, and ground stations as its nodes. The view within that view, which is used in SOIS, has the scope of a single vehicle, and has the instruments of the vehicle as its nodes and subnetworks as connections. We have occasionally drawn diagrams that mix these views to describe how a communication link terminates in a vehicle and in a ground station (for example). The view-within-a-view establishes a context for other views whose scope is limited to the same vehicle. The other vehicle-scoped views include minimally the physical/structural view and an electrical power distribution view and may also include a thermal distribution view, a propulsion view, and others. Perhaps all these vehicle-scoped views could be considered products of the physical/structural viewpoint. The correspondences between objects in the vehicle-scoped views would indicate where each instrument of the vehicle participates in each view. These vehicle-scoped correspondences would not extend to the nodes of the mission-scoped communication/connectivity view, except that a whole vehicle may correspond to a node in the mission-scoped communication/connectivity view.
The vehicle-scoped views described above could express the energy flows that you identified in your second point. I think that we can describe the interaction between energy flows and information flows that occurs in the instruments of a vehicle. That interaction would be the subject of the vehicle-scoped communication/connectivity view if the recursive structure is agreeable.
Ramon
From: Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Sent: Thursday, April 1, 2021 6:09 PM
To: r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>; 'Frederick Slane' <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>
Cc: SEA-SA <sea-sa at mailman.ccsds.org<mailto:sea-sa at mailman.ccsds.org>>
Subject: Re: [EXTERNAL] SC14 meeting
Hi Ray,
I like what you have done with this. It makes sense and it fits into the overall format used for the other viewpoints.
There are two items that occur to me that we may need to adjust:
1. I think we need to be careful about how we talk about correspondences to other views. This is especially tricky in this instance, where we essentially have a communications / connectivity view of physical Nodes, with a focus on how they connect for communication, and also the allocation of what we might call computational functions to the Nodes, and your Physical / Structural view of the same Nodes, where the concern is their physical connections and the allocation of what we might think of as energetic vs computational functions.
2. Related to that distinction, in this viewpoint, I think we would talk about those energetic flows instead of information flows (ref pg 4). So on pgs 5 & 6 I think we will want to avoid things like referencing IP addresses and control algorithms (except by correspondence) and instead would want to focus on the structural and energetic connections and even functions. Batteries, power panels, thrusters, etc all have energetic aspects which must be expressed in these views. But I think that any control / monitor interfaces should be handled in the communications / connectivity views.
Does this make sense to your way of thinking?
Thanks, Peter
From: Ramon Krosley <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>
Date: Wednesday, March 31, 2021 at 2:24 PM
To: Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>, Fred Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>
Cc: "Christian.Stangl at dlr.de<mailto:Christian.Stangl at dlr.de>" <Christian.Stangl at dlr.de<mailto:Christian.Stangl at dlr.de>>, 'Yonghui Huang' <huangyonghui at hotmail.com<mailto:huangyonghui at hotmail.com>>
Subject: RE: [EXTERNAL] SC14 meeting
Hi Fred and Peter,
The attachment contains the charts from the core deck that relate to the Physical/Structural view. I added a few charts at the end that provide additional information for discussion in the April 12 teleconference. There is an improved example of a physical/structural diagram adapted from OPS-SAT, using the drawing style of RASDS. The additional charts identify information that the physical/structural model provides to its users. The users of the model constitute an additional set of stakeholders.
Ramon
From: Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Sent: Monday, March 29, 2021 12:08 PM
To: Frederick Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>
Cc: Ray Krosley <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>; Christian.Stangl at dlr.de<mailto:Christian.Stangl at dlr.de>; Yonghui Huang <huangyonghui at hotmail.com<mailto:huangyonghui at hotmail.com>>
Subject: Re: [EXTERNAL] SC14 meeting
Hi Fred,
On the surface this sounds fine to me. I’d suggest that you try to create a revised set of the core deck we have been using that:
1. Moves things around to meet SC14 needs
2. Adds your desired expansions of the common / shared viewpoints (Services, Operations, and expanded Enterprise)
3. Adds the SC14 specific Physical / Structural viewpoint
4. Moves anything you think detracts from the SC14 message to backup
I assume that you will show these revised materials to all of us before showing them to SC14. Is that correct? Can we review them at the 12 April SAWG meeting or will that be too late for you? If you want to schedule a working session sooner, just to focus on this in a timely way, I’ll be happy to set that up.
Thanks, Peter
From: Fred Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>
Date: Monday, March 29, 2021 at 10:54 AM
To: Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>
Cc: Ramon Krosley <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>, "Christian.Stangl at dlr.de<mailto:Christian.Stangl at dlr.de>" <Christian.Stangl at dlr.de<mailto:Christian.Stangl at dlr.de>>, Yonghui Huang <huangyonghui at hotmail.com<mailto:huangyonghui at hotmail.com>>
Subject: Re: [EXTERNAL] SC14 meeting
I'll have updated SC14 slides from the larger presentation on my priority list today. I will intentionally leave some SC14 details for the SC14 architecture group to fill in.
I think an abridged version of slides to present, with full set as reading material will be good for the meeting.
The message I want to get across has three primary parts:
1- RASDS core establishes the framework and methodology (i.e., Views) for our common baseline. References ISO 42010: Systems and Software Engineering - Architecture Description
2- CCSDS extensions go into greater detail using the common baseline (CCSDS: ASL, SCCS ADD)
3- SC14 has its own story to tell and uses the common baseline for needed crosstalk.
-- Engineering basis for Systems and Operations Views. Engineering "V" describes Space System Design Engineering and Verification. Reference ISO 15288: Systems Engineering
-- Major SC14 extension Views are Physical, Operational, Services (expanded from previous RASDS), Enterprise (expanded back into CCSDS?)
I have one slide that will be for SC14 technical management related to how the Working Groups correlate to Views.
I would like to move the exploration of DoDAF to a footnote. While useful in our development work, I think it detracts from the primary product for the standards committees.
Cheers,
Fred
Frederick A. Slane
mobile
On Mon, Mar 29, 2021, 7:55 AM Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>> wrote:
Hi Fred,
Then we had best get hopping at the next CCSDS working meeting, right? Or do you think what we have already is suitable as it is?
Thanks, Peter
From: Fred Slane <frederick.slane at gmail.com<mailto:frederick.slane at gmail.com>>
Date: Sunday, March 28, 2021 at 2:10 PM
To: Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>, Ramon Krosley <r.krosley at andropogon.org<mailto:r.krosley at andropogon.org>>, "Christian.Stangl at dlr.de<mailto:Christian.Stangl at dlr.de>" <Christian.Stangl at dlr.de<mailto:Christian.Stangl at dlr.de>>, Yonghui Huang <huangyonghui at hotmail.com<mailto:huangyonghui at hotmail.com>>
Subject: [EXTERNAL] SC14 meeting
Hi Peter and All,
The SC14 meeting where I'll present our work is mid-April.
Fred
Frederick A. Slane
Executive Director
Space Infrastructure Foundation
731 North Tejon Street
Colorado Springs, CO 80904
freds at spacestandards.org<mailto:freds at spacestandards.org>
www.spacestandards.org<https://urldefense.us/v3/__http:/www.spacestandards.org__;!!PvBDto6Hs4WbVuu7!Z9QQVdae-rx4ji6veNe9h8S34Iun-nQ1ay7iS8bPwu6OtTPht_9R0HgYen4WiwjAniOwyUu9$>
+1-719-229-4252
"If you can't describe what you are doing as a process, you don't know what you're doing." ~W. Edwards Deming
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