diff --git a/app/models/config.py b/app/models/config.py
index e54cda781..865fa517d 100644
--- a/app/models/config.py
+++ b/app/models/config.py
@@ -383,7 +383,7 @@ class ScoDocSiteConfig(db.Model):
             cls.set("personalized_links", "")
             raise ScoValueError(
                 "Attention: liens personnalisés erronés: ils ont été effacés."
-            )
+            ) from exc
         return [PersonalizedLink(**item) for item in links_dict]
 
     @classmethod
@@ -395,6 +395,24 @@ class ScoDocSiteConfig(db.Model):
         data_links = json.dumps(links_dict)
         cls.set("personalized_links", data_links)
 
+    @classmethod
+    def assi_get_rounded_time(cls, label: str, default: str) -> float:
+        "Donne l'heure stockée dans la config globale sous label, en float arrondi au quart d'heure"
+        _round_time_str_to_quarter(cls.get(label, default))
+
+
+def _round_time_str_to_quarter(string: str) -> float:
+    """Prend une heure iso '12:20:23', et la converti en un nombre d'heures
+    en arrondissant au quart d'heure: (les secondes sont ignorées)
+    "12:20:00" -> 12.25
+    "12:29:00" -> 12.25
+    "12:30:00" -> 12.5
+    """
+    parts = [*map(float, string.split(":"))]
+    hour = parts[0]
+    minutes = round(parts[1] / 60 * 4) / 4
+    return hour + minutes
+
 
 class PersonalizedLink:
     def __init__(self, title: str = "", url: str = "", with_args: bool = False):
diff --git a/app/views/assiduites.py b/app/views/assiduites.py
index 88e9411be..c12eb3dcd 100644
--- a/app/views/assiduites.py
+++ b/app/views/assiduites.py
@@ -1,3 +1,29 @@
+# -*- coding: utf-8 -*-
+##############################################################################
+#
+# Gestion scolarite IUT
+#
+# Copyright (c) 1999 - 2023 Emmanuel Viennet.  All rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+#   Emmanuel Viennet      emmanuel.viennet@viennet.net
+#   module codé par Matthias Hartmann, 2023
+#
+##############################################################################
+
 import datetime
 
 from flask import g, request, render_template, flash
@@ -18,7 +44,6 @@ from app.models import (
     Assiduite,
     Justificatif,
     Departement,
-    FormSemestreInscription,
     Evaluation,
 )
 from app.views import assiduites_bp as bp
@@ -304,9 +329,11 @@ def signal_assiduites_etud():
 
     # Gestion des horaires (journée, matin, soir)
 
-    morning = get_time("assi_morning_time", "08:00:00")
-    lunch = get_time("assi_lunch_time", "13:00:00")
-    afternoon = get_time("assi_afternoon_time", "18:00:00")
+    morning = ScoDocSiteConfig.assi_get_rounded_time("assi_morning_time", "08:00:00")
+    lunch = ScoDocSiteConfig.assi_get_rounded_time("assi_lunch_time", "13:00:00")
+    afternoon = ScoDocSiteConfig.assi_get_rounded_time(
+        "assi_afternoon_time", "18:00:00"
+    )
 
     select = """
     <select class="dynaSelect">
@@ -1360,8 +1387,8 @@ def _dynamic_module_selector():
 def _timeline(formsemestre_id=None) -> HTMLElement:
     return render_template(
         "assiduites/widgets/timeline.j2",
-        t_start=get_time("assi_morning_time", "08:00:00"),
-        t_end=get_time("assi_afternoon_time", "18:00:00"),
+        t_start=ScoDocSiteConfig.assi_get_rounded_time("assi_morning_time", "08:00:00"),
+        t_end=ScoDocSiteConfig.assi_get_rounded_time("assi_afternoon_time", "18:00:00"),
         tick_time=ScoDocSiteConfig.get("assi_tick_time", 15),
         periode_defaut=sco_preferences.get_preference(
             "periode_defaut", formsemestre_id
@@ -1372,49 +1399,39 @@ def _timeline(formsemestre_id=None) -> HTMLElement:
 def _mini_timeline() -> HTMLElement:
     return render_template(
         "assiduites/widgets/minitimeline.j2",
-        t_start=get_time("assi_morning_time", "08:00:00"),
-        t_end=get_time("assi_afternoon_time", "18:00:00"),
+        t_start=ScoDocSiteConfig.assi_get_rounded_time("assi_morning_time", "08:00:00"),
+        t_end=ScoDocSiteConfig.assi_get_rounded_time("assi_afternoon_time", "18:00:00"),
     )
 
 
-def _non_work_days():
-    non_travail = sco_preferences.get_preference("non_travail", None)
+def _non_work_days() -> str:
+    """Abbréviation des jours non travaillés: "'sam','dim'".
+    donnés par les préférences du département
+    """
+    non_travail = sco_preferences.get_preference("non_travail")
     non_travail = non_travail.replace(" ", "").split(",")
     return ",".join([f"'{i.lower()}'" for i in non_travail])
 
 
-def _str_to_num(string: str):
-    parts = [*map(float, string.split(":"))]
-    hour = parts[0]
-    minutes = round(parts[1] / 60 * 4) / 4
-    return hour + minutes
-
-
-def get_time(label: str, default: str):
-    return _str_to_num(ScoDocSiteConfig.get(label, default))
-
-
-def _get_seuil():
+def _get_seuil() -> int:
+    """Seuil d'alerte des absences (en unité de la métrique),
+    tel que fixé dans les préférences du département."""
     return sco_preferences.get_preference("assi_seuil", dept_id=g.scodoc_dept_id)
 
 
-def _get_etuds_dem_def(formsemestre):
-    etuds_dem_def = [
-        (f.etudid, f.etat)
-        for f in FormSemestreInscription.query.filter(
-            FormSemestreInscription.formsemestre_id == formsemestre.id,
-            FormSemestreInscription.etat != "I",
-        ).all()
-    ]
-
-    template: str = '"£" : "$",'
-
-    json_str: str = "{"
-
-    for etud in etuds_dem_def:
-        json_str += template.replace("£", str(etud[0])).replace("$", etud[1])
-
-    if json_str != "{":
-        json_str = json_str[:-1]
-
-    return json_str + "}"
+def _get_etuds_dem_def(formsemestre) -> str:
+    """Une chaine json donnant les étudiants démissionnaires ou défaillants
+    du formsemestre, sous la forme
+    '{"516" : "D", ... }'
+    """
+    return (
+        "{"
+        + ", ".join(
+            [
+                f'"{ins.etudid}" : "{ins.etat}"'
+                for ins in formsemestre.inscriptions
+                if ins.etat != scu.INSCRIT
+            ]
+        )
+        + "}"
+    )