Page 36 - 2025S
P. 36

UEC Int’l Mini-Conference No.54                                                               29







                               Table 3: Hypervolume comparison across FDA benchmarks

              Algorithm            FDA1           FDA2           FDA3           FDA4           FDA5
              DNSGA-II           0.73 ± 0.04    0.68 ± 0.05    0.61 ± 0.07    0.59 ± 0.06    0.55 ± 0.08
              DNSGA-II.decs      0.82 ± 0.03   0.79 ± 0.04     0.74 ± 0.05    0.71 ± 0.05    0.69 ± 0.06
              DNSGA-II.obj      0.85 ± 0.02     0.77 ± 0.03   0.81 ± 0.03    0.78 ± 0.04    0.75 ± 0.05



            offs across dynamic environments. During rapid
            environmental changes (τ t = 10), the muta-
            tion probability p m consistently increased to the
            0.25-0.28 range within 2-3 generations, enabling
            swift exploration of new solution regions. Con-
            versely, in stable periods, p m decayed exponen-
            tially to 0.05-0.08, maintaining convergence to-
            ward optimal fronts.  Most significantly, this
            adaptive approach reduced hypervolume volatil-
            ity by 32% compared to fixed mutation rates in
            FDA 2 (σ HV = 0.04 vs. 0.059), demonstrating
            enhanced solution stability during transitional   Figure 4: Parameter adaptation dynamics dur-
            phases. The responsiveness of the parameter ad-   ing environmental changes in FDA 1 (τ t = 10).
            justment correlated directly with the magnitude   Top: HV progression; Middle: p m adaptation;
                                                              Bottom: ζ modulation.
            of HV degradation observed, with steeper ∆ HV
            values triggering more aggressive p m increases.
                                                              6.3   Computational Considerations
                                                              The proposed method introduced moderate
                                                              computational overhead. Experimental analy-
            6.2   Reinitialization Strategy Analysis          sis revealed a 15 - 20% run–time increase for
                                                              hyper-volume computation using the WFG al-
            Experimental evaluation confirmed three princi-   gorithm. The adaptation cost was measured at
            pal advantages of the diversity-guided reinitial-  AC = 0.85, compared to AC = 1.0 for DNSGA-
            ization approach. The strategy demonstrated       II.
            selective intervention capabilities by restricting
            reinitialization to 20-30% of the population dur-  6.4  Limitations
            ing environmental transitions, thereby preserv-
            ing valuable genetic material in undisturbed re-  The approach presents three constraints,among
            gions of the solution space. This selective ap-   which the first one is higher computational de-
            plication resulted in minimal disruption to pop-  mands in many-objective problems, the second
                                                              one is sensitivity to initialization parameters,
            ulation integrity, with solutions systematically
                                                              and the third one is necessary calibration for
            retained when the normalized diversity met-
            ric D norm > 0.6 indicated sufficient solution    specific change patterns.
            spread.  Most significantly, the approach de-
            livered efficient recovery performance, improv-   7    Conclusions
            ing the recovery ratio (RR) by 15-25% across
            all benchmark problems compared to fixed-re-      This research presents a comprehensive en-
            initialization baselines, with particularly strong  hancement of DNSGA-II for improved hyper-
            results observed in complex landscapes like       volume (HV) performance in dynamic environ-
            FDA 4 and FDA 5 where diversity maintenance       ments. Key findings demonstrate that the hy-
            proved critical.                                  brid adaptive mutation reinitialization strategy
   31   32   33   34   35   36   37   38   39   40   41