1 Introduction
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Aim 1: explore how qualifiers in an actual situation can be used and demonstrate their applicability.
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Aim 2: evaluate effects on qualifiers empirically, using different argumentation semantics.
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A generalization for the notion of an activity qualifier.
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Three instances of the general qualifier are defined: Capacity, Actuation and Performance qualifiers.
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We demonstrate the applicability of qualifiers based on “classical” argumentation semantics [11], using data from an experimental pilot.
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Results of the pilot test show: (1) partial correlation between ambiguities assessed by experts and our argument-based approach; and (2) usefulness when qualifiers are combined.
2 Background
2.1 Underlying logical language
2.2 Activity evaluation
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\( \textsf {Ax} = \{ ax_1, \dots , ax_j\} (j>0)\) is a set of atoms such that \( \textsf {Ax} \subseteq \mathcal {L}_P\). Ax denotes the set of actions in an AT model.
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\( \textsf {Go} = \{ g_1, \dots , g_k \} (k>0)\) is a set of atoms such that \( \textsf {Go} \subseteq \mathcal {L}_P\). Go denotes the set of goals in an AT model.
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\( \textsf {Op} = \{ o_1, \dots , o_l \} (l>0)\) is a set of atoms such that \( \textsf {Op} \subseteq \mathcal {L}_P\). Op denotes the set of goals in an AT model.
×
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P is a logic program. \( \mathcal {L}_P\) denotes the set of atoms which appear in P.
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\(\mathcal {H}_A = \{h_1, \dots , h_i\} \) is a set of atoms such that \(\mathcal {H}_A \subseteq \mathcal {L}_P\). \( \mathcal {H}_A \) denotes the set of hypothetical actions which an agent can perform in a world.
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\( \mathcal {G} = \{ g_1, \dots , g_j \} \) is a set of atoms such that \( \mathcal {G} \subseteq \mathcal {L}_P\). \( \mathcal {G} \) denotes a set of goals of an agent.
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\( \mathcal {O} = \{ o_1, \dots , o_k \} \) is a set of atoms such that \( \mathcal {O} \subseteq \mathcal {L}_P\). \( \mathcal {O} \) denotes a set of world observations of an agent.
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\( \textsf {AT} \) is an activity model of the form: \( \langle \textsf {Ax}, \textsf {Go}, \textsf {Op} \rangle \), following Definition 1.
\(F_1=\)
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\(\langle \{ g_1 \leftarrow ax_1 \wedge ax_2 \wedge o_2\wedge h_1; \ o_2 \leftarrow not \ o_1 \}, \)
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{\( o_2, ax_1, ax_2\)}, | |
\(h_1\), | |
\( g_1 \rangle \)
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... | |
\(F_7=\)
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\(\langle \{ g_4 \leftarrow g_5 \wedge ax_3 \wedge ax_4 \wedge ax_5\wedge o_3\wedge o_6 \wedge h_1;\)
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\(g_5 \leftarrow ax_6 \wedge o_2\wedge h_1;\ o_2 \leftarrow not \ o_1;\)
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\( \ o_3 \leftarrow not \ o_4; \ o_6 \leftarrow not \ o_5 \}, \)
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{\( o_2, o_3, o_6, ax_3, ax_4, ax_5, ax_6\)}, | |
\(h_1\), | |
\( g_4 \rangle \)
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\(F_{8}=\)
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\(\langle \{ g_5 \leftarrow ax_6 \wedge o_2\wedge h_1; \ o_2 \leftarrow not \ o_1\}, \)
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{\( o_2, ax_6\)}, | |
\(h_1\), | |
\( g_5 \rangle \)
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... | |
\(F_{10}=\)
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\(\langle \{ \lnot g_5 \leftarrow o_1\wedge h_2; \ o_1 \leftarrow not \ o_2\}, \)
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{\( o_16\)}, | |
\(h_2\), | |
\( \lnot g_5 \rangle \)
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... |
3 Qualifiers for evaluating activity
3.1 Instantiating qualifiers
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\( t_{ini} \) \( \mathsf {Output}_\mathrm{SEM}^{O} =\{ o_2\} \)
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\( t_{ini +1} \) \( \mathsf {Output}_\mathrm{SEM}^{O} =\{ o_2, o_3, o_6\} \)
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\( t_{ini +2} \) \( \mathsf {Output}_\mathrm{SEM}^{O} =\{ o_2\} \)
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\( t_{current} \) \( \mathsf {Output}_\mathrm{SEM}^{O} =\{ o_1\} \)
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\( t_{ini} \) \( \mathsf {Output}_\mathrm{SEM}^{A} =\{ ax_3, ax_7 ax_6\} \)
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\( t_{ini +1} \) \( \mathsf {Output}_\mathrm{SEM}^{A} =\{ ax_4, ax_7\} \)
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\( t_{ini +2} \) \( \mathsf {Output}_\mathrm{SEM}^{A} =\{ ax_3, ax_7 ax_6\} \)
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\( t_{current} \) \( \mathsf {Output}_\mathrm{SEM}^{A} =\{ ax_4, ax_7 ax_6\} \)
4 Demonstration of qualifiers in a use case
4.1 Pilot study setting
4.2 Data acquisition
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Test of standing balance included tandem, semi-tandem and side-by-side stands. For each stand, the interviewer first demonstrated the task using a video displayed in the Balansera mobile application (Fig. 7). The individual positioned their feet and the therapist asked if he/she was ready. The timing was stopped when individual moved their feet or grasped the therapist for support, or when 10 s had elapsed. Each participant began with semi-tandem stand. Those unable to hold the semi-tandem position for 10 s were evaluated with the feet in the side-by-side position. Those able to maintain the semi-tandem position for 10 s were further evaluated with the feet in full tandem position.
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For the test of the ability to rise from a chair, a straight-backed chair was placed next to the wall; participants were asked to fold their arms across their chest and to stand up from the chair five times using a normal speed.8 The timing starts from the initial sitting position to the final standing position at the end of the fifth stand.
4.3 Data analysis
4.4 Results of the demonstration
4.4.1 Applicability and utility of qualifiers
4.4.2 Qualifiers using different argumentation semantics
5 Discussion
5.1 Qualifiers in health domain
5.2 Qualifiers based on structured fragments
5.3 The role of argumentation semantics in qualifier calculus
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Credulous semantics usage: qualifiers using a credulous approach can be used to evaluate activity execution even under not rigorous achievement of goals or completion of actions or observations. A follow-up procedure over time, as is presented in Fig. 12 with stable semantics, was considered interesting by therapists.
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Skeptic semantics usage: our results using grounded semantics showed that the output of our system is sensitive to lack of observations information. Therapists consider this approach as a screening procedure, where individuals are a systematic assessment is done especially to detect anomalies with a minimal of ambiguity.
6 Conclusions
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Qualifiers depend on the output of a non-monotonic reasoning (NMR) process. In this sense, when more information is added to the activity context, the output of the argumentation process will change. This NMR procedure follows a health-care perspective where a physician can change an assessment of an individual when more information about her/him is available.
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We demonstrate our approach by using data from a pilot study. Our findings can be summarized as follows:
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A combined evaluation of qualifiers, Capacity and Performance can be an useful tool for expert analysis of activity execution, particularly in a process of follow-up keeping track the individual’s activity behavior and in screening methods for systematic detection of anomalies with a minimal of ambiguity.
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There is a considerable difference between the values of qualifiers when different argumentation semantics are considered. We evaluate qualifiers considering “classic” [11] semantics: stable, preferred, complete and grounded. We found that for the SPPB test, stable and preferred (credulous), complete and grounded (skeptical) semantics behave in the same manner.
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Our pilot experiment can not be considered as conclusive for assessing an individual’s physical condition; however, it helped therapists in the awareness of different sensor-based advantages and restrictions.
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