Organizations: University of Science and Technology of China, Hefei, China · Beijing University of Posts and Telecommunications, Beijing, China · Huawei Noah’s Ark Lab, Shenzhen, China
Recommendation model performance is intrinsically tied to the quality, volume, and relevance of their training data. To address common challenges like data sparsity and cold start, recent researchs have leveraged data from multiple auxiliary domains to enrich information within the target domain. However, inherent domain gaps can degrade the quality of mixed-domain data, leading to negative transfer and diminished model performance. Existing prevailing model-centric paradigm -- which relies on complex, customized architectures -- struggles to capture the subtle, non-structural sequence dependencies across domains, leading to poor generalization and high demands on computational resources. To address these shortcomings, we propose Taesar, a data-centric framework for target-aligned sequential regeneration, which employs a contrastive decoding mechanism to adaptively encode cross-domain context into target-domain sequences. It employs contrastive decoding to encode cross-domain context into target sequences, enabling standard models to learn intricate dependencies without complex fusion architectures. Experiments show Taesar outperforms model-centric solutions and generalizes to various sequential models. By generating enriched datasets, Taesar effectively combines the strengths of data- and model-centric paradigms. The code accompanying this paper is available at~ \textcolor{blue}{https://github.com/USTC-StarTeam/Taesar}.
Figures & tables
Figure 1. Cosine similarity heatmap of gradient directions across four domains in multi-domain sequential recommendation. Naïvely combining data from multiple domains for training induces gradient conflicts and inconsistencies.
Figure 2. Motivation of Taesar . We aim to eliminate the domain semantic gap at the source level, prior to model training, thereby transforming cross-domain mixed data into unified target-domain data. Left: Source items with high transferability are mapped to semantically closest target items, while others are discarded. Right: Regenerated data aligns cross-domain behavioral patterns with target-domain relevance, improving model gradients and target-domain performance.
Figure 3. Overview of Taesar . (1) In the first stage, Tri-model Pretraining , we construct three views of decoder models: a base model ( θM ), distinct source domain experts ( θS ), and a target domain expert ( θT ). (2) We select the base model, the target domain expert, and the source domain expert corresponding to the item to be transformed to regenerate mixed cross-domain sequences using global and local contrastive decoding among the three models. (3) Based on the two types of contrastive scores, we decide whether to replace a source-domain item with a target-domain item or to discard the source-domain item entirely.
# user
# item
# inter
Avg.
Dataset
( ∣U∣ )
( ∣V∣ )
( ∑xNx )
length
sparsity(%)
Books
70,672
526,955
13.12
99.98
Electronics
44,278
501,759
12.49
99.97
Sports
38,030
355,807
8.86
99.98
Tools
40,165
31,880
331,230
8.25
99.97
Table 1. Statistics of experimental datasets.
BEST: Books, Electronics, Sports, Tools
Books
Electronics
Method
HR@10
HR@20
NG@10
NG@20
MRR@10
MRR@20
HR@10
HR@20
NG@10
NG@20
MRR@10
MRR@20
SASRec
0.0563
0.0660
0.0371
0.0395
0.0311
0.0317
0.0350
0.0430
0.0257
0.0277
0.0228
0.0234
GRU4Rec
0.0384
0.0450
0.0283
0.0300
0.0253
0.0257
0.0247
0.0325
0.0184
0.0204
0.0165
0.0170
GCE-GNN
0.0598
0.0733
0.0447
0.0481
0.0400
0.0409
0.0353
0.0424
0.0286
0.0304
0.0266
0.0271
CL4SRec
0.0585
0.0708
0.0442
0.0473
0.0398
0.0406
0.0347
0.0424
0.0278
0.0298
0.0257
0.0262
Table 2. Overall performance of Taesar compared with state-of-the-art multi-domain sequential recommendation methods, and its generalization across single-domain models with different architectures. Best results are in bold, second-best underlined.
Electronics
Variants
HR@10
HR@20
NG@10
NG@20
MRR@10
MRR@20
w/o DSA
0.0352
0.0434
0.0237
0.0258
0.0202
0.0207
DSA w/o DSP
0.0350
0.0450
0.0241
0.0266
0.0208
0.0215
DSP w/o SDE
0.0398
0.0472
0.0282
0.0300
0.0239
0.0247
DSP w/o GCS
0.0439
0.0523
0.0289
0.0310
0.0242
0.0247
DSP w/o LCS
0.0431
0.0512
0.0278
0.0299
0.0231
0.0236
Table 3. Ablation results of Taesar on different designs of Pretraining, Domain-Specific Adaptation, and Adaptive Contrastive Decoding strategies.
Figure 4. Schematic illustration of the adaptive contrastive decoding phase: (a) selection of transferable items from source domain S (Electronics), and (b) distribution-level mapping to target domain T (Books).
Figure 5. Comparison of data statistics between the original and regenerated Books domain dataset: (a) item frequency, (b) long-tail coverage, and (c) sequence length distribution.