Describe the bug
ReferenceError on global stack using inside the trusted server, we need to find a method to resolve it because it is the base of the spatial cloaking.

To Reproduce
Steps to reproduce the behavior:

1. Start the Android Emulator on App/
2. Install Application on Run
3. Enable Microphone and GPS
4. Go in /Server/ directory
5. Execute npm run trust on the first shell (Port: 3000)
6. Execute npm run backend on the second shell (Port: 4000)
7. Send Record on App Button

Expected behavior
I expected to load in the database the spatial location or nothing in case of making a pending state

Additional context
I used global.stack and exports.stack to define a real reference on the server-trusted but it seems like blind on stack variable initialization.

Describe the bug
Decibels noise measurements are not real in the MediaRecorder.getMaxAmplitude() and differ in according to the API versions in Android devices.

Expected behavior
Given a sound recording, returns a level of decibels around 70 dB (residential areas) to 90 dB (commercial areas) in according to the middle noise of a metropolitan city.

Code

REFERENCE = 0.1;
public double getNoiseLevel() 
{
    //Log.d("SPLService", "getNoiseLevel() ");
    int x = mRecorder.getMaxAmplitude();
    double x2 = x;
    Log.d("SPLService", "x="+x);
    double db = (20 * Math.log10(x2 / REFERENCE));
    //Log.d("SPLService", "db="+db);
    if(db>0)
    {
        return db;
    }
    else
    {
        return 0;
    }
}

Additional context
The REFERENCE value is not 0.1 and the values in decibels are like 20 to 40 dB.

In the implementation of the dashboard missed the following points:

1. Fixing settings centroids to off for default.
2. Sliders alignments
3. Remove arrow in slider
4. Adding 404 error handle in Ajax (with field named "error")
5. Adding marker with popup for prediction (single-step version)
6. Setting of popup for markers (Noise Decibels, Quality of Service, Privacy) and only "Noise Decibels" for predicted markers.
7. In the cluster polygon, adding a popup with mean of noise decibels named "Mean Noise Decibels"

To Do
Inside the utility.js there are geoJSON structure construction. Manage them using QoS and privacy attributes taken from the database attribute.

App Error Stacktrace

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.crowdsensingapp, PID: 22132
java.lang.OutOfMemoryError: Could not allocate JNI Env: Failed anonymous mmap(0x0, 8192, 0x3, 0x2, 61, 0): Permission denied. See process maps in the log.
at java.lang.Thread.nativeCreate(Native Method)
at java.lang.Thread.start(Thread.java:733)
at com.android.volley.RequestQueue.start(RequestQueue.java:127)
at com.android.volley.toolbox.Volley.newRequestQueue(Volley.java:91)
at com.android.volley.toolbox.Volley.newRequestQueue(Volley.java:67)
at com.android.volley.toolbox.Volley.newRequestQueue(Volley.java:102)
at com.example.crowdsensingapp.MapsActivity.getMeanDb(MapsActivity.java:301)
at com.example.crowdsensingapp.MapsActivity$5.onLocationResult(MapsActivity.java:228)
at com.google.android.gms.internal.location.zzau.notifyListener(Unknown Source:4)
at com.google.android.gms.common.api.internal.ListenerHolder.notifyListenerInternal(Unknown Source:17)
at com.google.android.gms.common.api.internal.ListenerHolder$zaa.handleMessage(Unknown Source:5)
at android.os.Handler.dispatchMessage(Handler.java:106)
at com.google.android.gms.internal.base.zap.dispatchMessage(Unknown Source:8)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

How to execute bug

Start applications and wait until the crash, it is caused by OutOfMemoryError for permissions to allocate JNI environment.

To Do

1. Clean dashboard from useless buttons/options
2. Make sidebar and not cards management
3. Dropout views
4. Insert every options from the backend server
5. Connect to service backend API and show results

Describe the bug
Spatial Cloaking Management and Comprehension

To Reproduce
Can't, it is a logical issue

Expected behavior
When the android app runs and sends data, how it should be display these infos? How should manage these data in the back-end and in the database structure?

Screenshots
Not applicable

App Android
Nell'App Android verrà inviato un flag "automatic" in grado di definire se, per quel particolare punto o set di punti inviati dall'utente, si deve applicare un settaggio back-end per il k e il range tale che si migliori il trade-off tra Privacy e QoS.

Server Trusted
Nel server trusted ci sta uno stack con i punti da dover aggregare in modo da ottenere come risultato un punto spaziale dato dallo spatial cloaking e prendendo un filtraggio per range, k e user_id.

Quando un punto "automatic" entra all'interno del server trusted, bisogna settare k, range tale che:

1. k viene massimizzato in modo da ottenere il valore massimo di Privacy possibile, considerando i valori dello stack
2. Minimizzare il valore del range per minimizzare l'errore quadratico medio tra il punto spaziale e il punto reale, ossia massimizzare il QoS.

In modo da ottimizzare trade-off = a * P + (1-a) * Q basandosi su un a dato dall'utente.
Ciò che si otterrà è un punto tale che avrà il massimo trade-off Privacy-QoS tra le possibili combinazioni di k, range del punto x inserito con i vari punti ancora all'interno dello stack.

Server Backend
Riceverà i punti dello spatial cloaking in cui:

1. L'indice del QoS è calcolato seguendo una media quadratica delle differenze tra i db dei punti generati e quelli del nodo spaziale.
2. L'indice di Privacy che è calcolato andando a vedere la distanza media tra il nodo spaziale e i punti da cui è stato generato.

We need to evaluate QoS and privacy metrics in the same domain. The solution is to establish a value domain for both values and normalize them before the Trade-off elaboration. After that, the trade-off can be a good level of classification about noise management in a specific area of interest.

During the automatic range setting it's better to have a range between 0 and 3000 than 1 to 2999.
That's because we calculate the automatic range in the way:

Math.floor(Range * Alpha * 10 / 10) which should be an integer between 0 and 3000 (actually is from 1 to 2999)

Correction should be on the Android App scripts in the settings session.

Metrica di privacy: distanza media tra la posizione reale dell’utente e quella inviata alla piattaforma

Metrica di QoS: Metrica di QoS, sotto forma di errore quadratico medio sulle misurazioni di rumore