## Why doesn’t relu cause back propegation to get stuck

Say you have a neural net that is being trained using back propagation and you are using relu activation. Say the input to a node is a weighted sum of the previous layer with a bias term and say for a particular data point, this weighted sum plus bias is negative. Then relu returns 0. Notice the change in the loss as a function of the change in one of these weights or the bias is 0. Therefore the network won’t improve the bias as the network does back propagation. Why is this not a problem?

## Penetration testing: stuck with injecting upload form

I have to do an assignment for a penetration testing exam but i’m a little bit stuck.

Among all the vulnerabilities i have to inject an upload form but it behaves weird, if i upload a file (even an image or similar) it does not do anything so i can’t tell if the file has been uploaded or not, there is no error message , anything useful.

I have a LFI vulnearbility so i can check files in /var/www/html and get the source but i can’t find anything useful, basically i have only .php frontend files :\

What vulnerability can i expect? or are there any tests that i can do?

This is the post request of burp-suite when i upload: https://imgur.com/a/Z7zeFoQ

Thank you 🙂

## Oracle19C installation is stuck at executing datapatch in Windows 10 using dbca

I tried using dbca. There are no errors. It just hangs. I tried leaving it running for 4 hours. It is always stuck at 36% even after multiple tries.

Logs:

[progressPage.flowWorker] [ 2020-05-25 00:26:04.206 IST ] [CloneDBCreationStep.executeImpl:823] executing datapatch %ORACLE_HOME%\OPatch\datapatch.bat

## Stuck with an idea [closed]

I am trying to make a scenario for my friends, but I am stuck, with implementing an idea.

Imagine that we have a magic artifact, for which both the protagonists and the antagonists are looking for. The antagonists, have a very specific plan, which plan MUST succeed, so I am able to continue the story further.

(The plan, more exactly is, that they are looking for a ritual, with which they can raise a mummy, and this ritual is hidden in a crypt. They already have the mummy in question, in a completely different location, so they will only need the ritual, which can either be written on something that they can take with them, but it just as well might be written on the walls of the crypt, from where they can note it down.)

Now, the use of this magic artifact, can be anything, it just has to be in the story, so that it gives the players something to chase. I could make it, a key, that opens the crypt in question, but in that case, what if the players achieve to lay hands on this artifact, before the antagonists? If this artifact is the only way for the antagonists to reach their goals, then they must acquire it, but if the players have no chance of acquiring or holding on to this artifact, then this artifact has no point at all imo.

As an additional info, in the crypt where this ritual is located, a star-spawn dwells, which can either be hostile to the players, to the antagonists or both. (I have not decided yet about this).

Summarized: I am looking for a scope for this artifact, which isn’t too powerful, so that it won’t prevent neither the antagonists nor the protagonists from reaching their goals, but still, it shouldn’t be meaningless either.

## I’ve been asked to change this statements into predicate form by using standard form but I’m stuck

I studied Artificial intelligence a long time ago and I’ve had no interest in it. I studied Artificial intelligence a long time ago and I’ve had no interest in it. But recently one of my friends asked me to change the following states into predicate form by using a standard form. Can someone help me?

• Marin is married to Sylvia who has a daughter Joy. • Harry is the son of Amos who is married to Joy. • The parent of one’s parent is his/her grandparent.
• If a person is married to another person who has a child then the first person is also a parent of the child.
• If a person is married to another person then the latter person is married to the former.

Change these sentences to predicate form, by using the standard form of logic and the following predicates: parent(X, Y), grandparent(X, Y), and married_to (X, Y).

I know it may look simple for some of you. But I recently went to another field about 2 years ago. Thank you.

## What do you do when avoiding railroading just gives you stuck players?

I’m seeking some newbie GM advice. I’m an experienced rpg player, but am much less experienced as a GM

I was recently running an D&D 5e adventure, where the players would be investigating in a town that had some problems with trade caravans being attacked. They started at the local Sheriffs office who tipped them that a local relatively new thieving guild was active in the area. The thieving guild wasn’t raiding the caravans, but I thought it might add a little plot twist to get the guild involved. My thought was to have the PCs eventually figure out that the guild wasn’t behind the problem and would need to investigate the local country-side to discover the problem. I had a few encounters written out, but I wasn’t fully sure how the PCs would reach their end goal of figuring out the source of the problem. I guess I thought that over-planning would be railroading and I wanted to give the players some freedom.

The players were often confused and unsure what to do. There wasn’t quite the excitement I was hoping for. They were eventually invited to a parley with the thieves guild but were not sure what to do with the thieves, so eventually just attacked them. It was ok, but not spectacular.

What do you do when your players seem stuck?

## CFG to CNF, but stuck on the last few steps

I recently learned about the conversion, but I seem to be stuck.

I need to convert the following CFG to CNF:

$$S → XY$$

$$X → abb|aXb|e$$

$$Y → c|cY$$

1. There is no S on the right side, so I did not need to add another
2. I removed the null productions $$X → e$$

$$S→XY|Y$$

$$X→abb|aXb|ab|$$

$$Y→c|cY|$$

1. I removed unit production $$S→Y$$ $$Y→c$$ with $$S→c$$

2. There are no production rules which have more than 2 variables

3. Here, I struggle. I am not allowed to have a terminal symbol and a variable together, but I am not sure how to get rid of these.

New grammar after step 4:

$$S→XY|c$$

$$X→abb|aXb|ab$$

$$Y→ZY$$

$$Z→c$$

I managed to replace the symbol c with Z, and added the new rule, so that seems fixed. However, I am unsure what do do with $$aXb$$.

Is this okay so far? if yes, what step should i take next?

## Unity Dropdown Stays Stuck Open

As can be seen in the following video:

The dropdown stays stuck open when Unity launches the game. This happens even with a non-modified dropdown that is plopped as a new UI object inside the canvas.

I tried a blank project, and the issue does not reproduce. I tried in a blank project, and the dropdown works. I tried researching a solution, but not too sure how to find one with this problem. Maybe someone here will have an idea or two.

@Sven

Was something recently changed with Blog Comment, Image Comment, Pingback or Trackback?

I have projects that only target Blog Comment, Image Comment, Pingback and Trackback. And these are the only projects that are getting stuck. These projects build links but then get stuck and do not proceed. So I manually have to stop and refresh within SER and restart projects. What is also strange is when I restart these projects the Submitted and Verified numbers go backwards by thousands. Another strange thing happens is that when I stop these projects the active thread count still shows example T:35.

Other projects that target all other platforms like Article, Directory, Forums, Social Networks/ Bookmark, Guestbooks, etc. work fine and never get stuck.

This has created a huge problem for me since I have to keep on restarting these projects over and over, please fix.

## Slow queries constantly getting stuck on WordPress database of ~100,000 posts

I am constantly getting stuck SELECT queries on my wordpress databases like the following:

Many of the SELECT queries that get stuck are fairly ordinary, such as pulling the last 10 posts of an author or pulling 10 posts in a category – these are normal WordPress core queries, not from any plugin. My WordPress databases that get afflicted with this have around 100,000 rows in the wp_posts table, with a size of around 1GB. This is an example of the largest tables from one of the databases:

My dedicated server is has 4 CPU cores @ 3.4 GHz and 8 GB DDR4 RAM. For this server and these databases, should these kinds of issues be happening? What can I do to make normal WordPress queries always run without getting stuck? I have tried changing from MyISAM to InnoDB with no effect, as well as changing different settings in my.cnf – here it is currently:

``[mysqld] pid-file = /var/run/mysqld/mysqld.pid log-error=/var/lib/mysql/errorlog.err performance-schema=0 default-storage-engine=MyISAM max_allowed_packet=268435456 open_files_limit=10000 slow_query_log=ON log_slow_verbosity=1 innodb_buffer_pool_size=1G aria_pagecache_buffer_size=512M query_cache_size=0 query_cache_type=0 query_cache_limit=0 join_buffer_size=512K tmp_table_size=32M max_heap_table_size=32M table_definition_cache=1200 ``

And the result of running https://github.com/major/MySQLTuner-perl:

``[root@hostname ~]# perl mysqltuner.pl --host 127.0.0.1  >>  MySQLTuner 1.7.19 - Major Hayden <major@mhtx.net>  >>  Bug reports, feature requests, and downloads at http://mysqltuner.com/  >>  Run with '--help' for additional options and output filtering  [--] Skipped version check for MySQLTuner script [--] Performing tests on 127.0.0.1:3306 [OK] Currently running supported MySQL version 10.3.20-MariaDB-log [OK] Operating on 64-bit architecture  -------- Log file Recommendations ------------------------------------------------------------------ [OK] Log file /var/lib/mysql/errorlog.err exists [--] Log file: /var/lib/mysql/errorlog.err(764K) [OK] Log file /var/lib/mysql/errorlog.err is readable. [OK] Log file /var/lib/mysql/errorlog.err is not empty [OK] Log file /var/lib/mysql/errorlog.err is smaller than 32 Mb [!!] /var/lib/mysql/errorlog.err contains 1571 warning(s). [!!] /var/lib/mysql/errorlog.err contains 1424 error(s). [--] 124 start(s) detected in /var/lib/mysql/errorlog.err [--] 1) 2019-11-25  6:31:15 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 2) 2019-11-25  6:08:45 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 3) 2019-11-25  5:47:35 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 4) 2019-11-25  5:34:11 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 5) 2019-11-25  5:22:58 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 6) 2019-11-25  5:02:11 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 7) 2019-11-25  4:33:46 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 8) 2019-11-25  4:27:54 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 9) 2019-11-25  4:21:59 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 10) 2019-11-25  4:21:52 0 [Note] /usr/sbin/mysqld: ready for connections. [--] 123 shutdown(s) detected in /var/lib/mysql/errorlog.err [--] 1) 2019-11-25  6:31:08 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 2) 2019-11-25  6:08:26 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 3) 2019-11-25  5:47:27 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 4) 2019-11-25  5:33:59 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 5) 2019-11-25  5:22:55 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 6) 2019-11-25  5:02:05 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 7) 2019-11-25  4:33:42 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 8) 2019-11-25  4:27:47 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 9) 2019-11-25  4:21:58 0 [Note] /usr/sbin/mysqld: Shutdown complete [--] 10) 2019-11-25  4:21:48 0 [Note] /usr/sbin/mysqld: Shutdown complete  -------- Storage Engine Statistics ----------------------------------------------------------------- [--] Status: +Aria +CSV +InnoDB +MEMORY +MRG_MyISAM +MyISAM +PERFORMANCE_SCHEMA +SEQUENCE  [--] Data in MyISAM tables: 2.3G (Tables: 1379) [--] Data in InnoDB tables: 2.7G (Tables: 284) [OK] Total fragmented tables: 0  -------- Analysis Performance Metrics -------------------------------------------------------------- [--] innodb_stats_on_metadata: OFF [OK] No stat updates during querying INFORMATION_SCHEMA.  -------- Security Recommendations ------------------------------------------------------------------ [OK] There are no anonymous accounts for any database users [OK] All database users have passwords assigned [--] There are 620 basic passwords in the list.  -------- CVE Security Recommendations -------------------------------------------------------------- [OK] NO SECURITY CVE FOUND FOR YOUR VERSION  -------- Performance Metrics ----------------------------------------------------------------------- [--] Up for: 3m 3s (36K q [199.732 qps], 1K conn, TX: 222M, RX: 33M) [--] Reads / Writes: 96% / 4% [--] Binary logging is disabled [--] Physical Memory     : 7.6G [--] Max MySQL memory    : 2.1G [--] Other process memory: 0B [--] Total buffers: 1.7G global + 3.2M per thread (151 max threads) [--] P_S Max memory usage: 0B [--] Galera GCache Max memory usage: 0B [OK] Maximum reached memory usage: 1.7G (22.90% of installed RAM) [OK] Maximum possible memory usage: 2.1G (28.14% of installed RAM) [OK] Overall possible memory usage with other process is compatible with memory available [OK] Slow queries: 0% (11/36K) [OK] Highest usage of available connections: 14% (22/151) [OK] Aborted connections: 0.00%  (0/1174) [!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance [OK] Query cache is disabled by default due to mutex contention on multiprocessor machines. [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 6K sorts) [!!] Joins performed without indexes: 50 [!!] Temporary tables created on disk: 70% (1K on disk / 2K total) [OK] Thread cache hit rate: 98% (22 created / 1K connections) [OK] Table cache hit rate: 98% (444 open / 450 opened) [!!] table_definition_cache(1200) is lower than number of tables(1928) [OK] Open file limit used: 5% (580/10K) [OK] Table locks acquired immediately: 99% (25K immediate / 25K locks)  -------- Performance schema ------------------------------------------------------------------------ [--] Performance schema is disabled. [--] Memory used by P_S: 0B [--] Sys schema is installed.  -------- ThreadPool Metrics ------------------------------------------------------------------------ [--] ThreadPool stat is enabled. [--] Thread Pool Size: 8 thread(s). [--] Using default value is good enough for your version (10.3.20-MariaDB-log)  -------- MyISAM Metrics ---------------------------------------------------------------------------- [!!] Key buffer used: 35.6% (47M used / 134M cache) [OK] Key buffer size / total MyISAM indexes: 128.0M/170.4M [OK] Read Key buffer hit rate: 99.9% (22M cached / 22K reads) [OK] Write Key buffer hit rate: 99.3% (824 cached / 818 writes)  -------- InnoDB Metrics ---------------------------------------------------------------------------- [--] InnoDB is enabled. [--] InnoDB Thread Concurrency: 0 [OK] InnoDB File per table is activated [!!] InnoDB buffer pool / data size: 1.0G/2.7G [!!] Ratio InnoDB log file size / InnoDB Buffer pool size (9.375 %): 48.0M * 2/1.0G should be equal to 25% [!!] InnoDB buffer pool <= 1G and Innodb_buffer_pool_instances(!=1). [--] Number of InnoDB Buffer Pool Chunk : 8 for 8 Buffer Pool Instance(s) [OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances [OK] InnoDB Read buffer efficiency: 99.71% (10795186 hits/ 10826096 total) [OK] InnoDB Write log efficiency: 98.51% (39722 hits/ 40324 total) [OK] InnoDB log waits: 0.00% (0 waits / 602 writes)  -------- AriaDB Metrics ---------------------------------------------------------------------------- [--] AriaDB is enabled. [OK] Aria pagecache size / total Aria indexes: 512.0M/1B [OK] Aria pagecache hit rate: 98.7% (130K cached / 1K reads)  -------- TokuDB Metrics ---------------------------------------------------------------------------- [--] TokuDB is disabled.  -------- XtraDB Metrics ---------------------------------------------------------------------------- [--] XtraDB is disabled.  -------- Galera Metrics ---------------------------------------------------------------------------- [--] Galera is disabled.  -------- Replication Metrics ----------------------------------------------------------------------- [--] Galera Synchronous replication: NO [--] No replication slave(s) for this server. [--] Binlog format: MIXED [--] XA support enabled: ON [--] Semi synchronous replication Master: OFF [--] Semi synchronous replication Slave: OFF [--] This is a standalone server  -------- Recommendations --------------------------------------------------------------------------- General recommendations:     Control warning line(s) into /var/lib/mysql/errorlog.err file     Control error line(s) into /var/lib/mysql/errorlog.err file     MySQL was started within the last 24 hours - recommendations may be inaccurate     Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1     We will suggest raising the 'join_buffer_size' until JOINs not using indexes are found.              See https://dev.mysql.com/doc/internals/en/join-buffer-size.html              (specially the conclusions at the bottom of the page).     When making adjustments, make tmp_table_size/max_heap_table_size equal     Reduce your SELECT DISTINCT queries which have no LIMIT clause     Performance schema should be activated for better diagnostics Variables to adjust:     join_buffer_size (> 512.0K, or always use indexes with JOINs)     tmp_table_size (> 32M)     max_heap_table_size (> 32M)     table_definition_cache(1200) > 1928 or -1 (autosizing if supported)     performance_schema = ON enable PFS     innodb_buffer_pool_size (>= 2.7G) if possible.     innodb_log_file_size should be (=128M) if possible, so InnoDB total log files size equals to 25% of buffer pool size.     innodb_buffer_pool_instances (=1) ``

I’ve tried these suggestions along with every other possible thing it feels like (caching, optimizing tables etc) and still queries get stuck over and over, causing connections to be stuck in apache with a ‘sending reply’ status and causing websites not to load. What else can I try? Should I upgrade to a more powerful server?